/* ══════════════════════════════════════════════════════════════
   ASL Fingerspelling Translator — Professional Redesign
   Theme: Medical Dark + Teal  |  Font: Inter
   Author: Nishanth S. — ENEB408B Spring 2026
   ══════════════════════════════════════════════════════════════ */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800;900&display=swap');

*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }

/* ── Design Tokens ── */
:root {
  --bg:          #0b1929;
  --bg2:         #0e1f33;
  --surface:     #102235;
  --surface2:    #163047;
  --surface3:    #1b3a56;
  --teal:        #0e7490;
  --teal-light:  #22d3ee;
  --teal-dim:    rgba(14,116,144,0.15);
  --teal-glow:   rgba(14,116,144,0.28);
  --teal-border: rgba(14,116,144,0.40);
  --success:     #10b981;
  --success-dim: rgba(16,185,129,0.15);
  --warning:     #f59e0b;
  --warning-dim: rgba(245,158,11,0.15);
  --danger:      #ef4444;
  --danger-dim:  rgba(239,68,68,0.15);
  --text:        #dde8f0;
  --text-dim:    #6e93b0;
  --text-muted:  #435f77;
  --border:      #1c3348;
  --border-dim:  #162b3e;
  --radius-sm:   6px;
  --radius:      10px;
  --radius-lg:   14px;
  --shadow:      0 4px 20px rgba(0,0,0,0.45), 0 1px 4px rgba(0,0,0,0.3);
  --shadow-teal: 0 0 0 1px var(--teal-border), 0 0 20px var(--teal-glow);
  --font:        'Inter', system-ui, -apple-system, sans-serif;
}

/* ── Base ── */
html { font-size: 16px; }
body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background-image:
    linear-gradient(rgba(14,116,144,0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(14,116,144,0.03) 1px, transparent 1px);
  background-size: 32px 32px;
  pointer-events: none;
  z-index: 0;
}
.splash, header, .app-shell, footer { position: relative; z-index: 1; }

/* ══════════════════════════════════════════════
   SPLASH
══════════════════════════════════════════════ */
.splash {
  position: fixed; inset: 0; z-index: 9999;
  background: var(--bg);
  display: flex; align-items: center; justify-content: center;
  transition: opacity 0.8s ease;
}
.splash.splash-fade { opacity: 0; pointer-events: none; }
.splash-content {
  display: flex; flex-direction: column; align-items: center;
  gap: 36px; padding: 24px; text-align: center; max-width: 460px; width: 100%;
}
.splash-brand { display: flex; flex-direction: column; align-items: center; gap: 14px; }
.splash-icon-wrap {
  width: 68px; height: 68px;
  background: var(--teal-dim); border: 2px solid var(--teal-border);
  border-radius: 18px;
  display: flex; align-items: center; justify-content: center;
  animation: splashPulse 2s ease-in-out infinite;
}
.splash-hand-icon { width: 34px; height: 34px; color: var(--teal-light); }
@keyframes splashPulse {
  0%,100% { box-shadow: 0 0 0 0 var(--teal-glow); }
  50%      { box-shadow: 0 0 0 12px rgba(14,116,144,0); }
}
.splash-title { font-size: 1.5rem; font-weight: 800; color: var(--text); letter-spacing: -0.5px; }
.splash-subtitle { font-size: 0.88rem; color: var(--text-dim); }
.splash-loader-wrap { width: 100%; display: flex; flex-direction: column; gap: 9px; }
.splash-bar-track { width: 100%; height: 4px; background: var(--surface2); border-radius: 2px; overflow: hidden; }
.splash-bar-fill {
  height: 100%; width: 30%;
  background: linear-gradient(90deg, var(--teal), var(--teal-light));
  animation: splashScroll 1.8s ease-in-out infinite;
}
@keyframes splashScroll {
  0%   { width: 0%; margin-left: 0; }
  50%  { width: 60%; }
  100% { width: 0%; margin-left: 100%; }
}
.splash-status-text { font-size: 0.78rem; color: var(--text-dim); font-weight: 500; }
.splash-meta { font-size: 0.7rem; color: var(--text-muted); }

/* ══════════════════════════════════════════════
   NAVBAR
══════════════════════════════════════════════ */
.navbar {
  position: sticky; top: 0; z-index: 100;
  background: rgba(11,25,41,0.97);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
  padding: 0 20px;
}
.nav-inner {
  display: flex; align-items: center; justify-content: space-between;
  max-width: 1400px; margin: 0 auto; height: 58px; gap: 12px;
}
.nav-brand { display: flex; align-items: center; gap: 10px; flex-shrink: 0; }
.nav-icon-wrap {
  width: 34px; height: 34px;
  background: var(--teal-dim); border: 1px solid var(--teal-border);
  border-radius: 8px; display: flex; align-items: center; justify-content: center; flex-shrink: 0;
}
.nav-hand-icon { width: 18px; height: 18px; color: var(--teal-light); }
.nav-titles { display: flex; flex-direction: column; gap: 1px; }
.nav-title { font-size: 0.92rem; font-weight: 700; color: var(--text); letter-spacing: -0.2px; white-space: nowrap; }
.nav-sub { font-size: 0.65rem; color: var(--teal-light); font-weight: 500; letter-spacing: 0.5px; text-transform: uppercase; }

/* Page navigation buttons */
.nav-pages { display: flex; align-items: center; gap: 4px; }
.nav-page-btn {
  display: flex; align-items: center; gap: 6px;
  padding: 7px 14px;
  border: 1px solid transparent;
  border-radius: var(--radius);
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  font-size: 0.8rem; font-weight: 600; font-family: var(--font);
  letter-spacing: 0.2px;
  transition: all 0.2s;
  white-space: nowrap;
}
.nav-page-btn svg { width: 15px; height: 15px; flex-shrink: 0; }
.nav-page-btn:hover { color: var(--text-dim); background: rgba(255,255,255,0.04); }
.nav-page-btn.active {
  color: var(--teal-light);
  background: var(--teal-dim);
  border-color: var(--teal-border);
}

.nav-right { display: flex; align-items: center; gap: 8px; flex-shrink: 0; }
.model-chip {
  padding: 4px 11px; border-radius: 20px;
  font-size: 0.68rem; font-weight: 600; letter-spacing: 0.3px; white-space: nowrap;
}
.model-chip.loading { background: var(--warning-dim); color: var(--warning); border: 1px solid rgba(245,158,11,0.35); }
.model-chip.ready   { background: var(--success-dim); color: var(--success); border: 1px solid rgba(16,185,129,0.35); }
.model-chip.error   { background: var(--danger-dim);  color: var(--danger);  border: 1px solid rgba(239,68,68,0.35); }
.nav-badge {
  padding: 4px 11px; border-radius: 20px;
  font-size: 0.66rem; font-weight: 600;
  background: var(--teal-dim); color: var(--teal-light);
  border: 1px solid var(--teal-border); white-space: nowrap;
}

/* ══════════════════════════════════════════════
   APP SHELL — left column (video) + right column (pages)
══════════════════════════════════════════════ */
.app-shell {
  flex: 1;
  display: grid;
  grid-template-columns: min(420px, 40vw) 1fr;
  gap: 0;
  max-width: 1400px;
  margin: 0 auto;
  width: 100%;
  align-items: start;
}

/* ── LEFT: Video column ── */
.video-column {
  position: sticky;
  top: 58px;
  height: calc(100vh - 58px);
  overflow-y: auto;
  padding: 16px 16px 16px 20px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  border-right: 1px solid var(--border);
}

.video-container {
  position: relative;
  width: 100%;
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1.5px solid var(--border);
  background: #000;
  aspect-ratio: 4/3;
  box-shadow: var(--shadow);
  transition: border-color 0.3s, box-shadow 0.3s;
  flex-shrink: 0;
}
.video-container.hand-active {
  border-color: var(--teal);
  box-shadow: var(--shadow-teal), var(--shadow);
}
#webcam { width: 100%; height: 100%; object-fit: cover; transform: scaleX(-1); display: block; }
#overlay { position: absolute; inset: 0; width: 100%; height: 100%; transform: scaleX(-1); }

/* Hand status badge */
.hand-status {
  position: absolute; bottom: 10px; left: 50%; transform: translateX(-50%);
  background: rgba(11,25,41,0.85); backdrop-filter: blur(8px);
  padding: 5px 14px 5px 28px;
  border-radius: 20px; font-size: 0.7rem; font-weight: 500;
  color: var(--text-dim); border: 1px solid var(--border);
  transition: all 0.3s; white-space: nowrap;
}
.hand-status::before {
  content: ''; position: absolute; left: 11px; top: 50%; transform: translateY(-50%);
  width: 7px; height: 7px; border-radius: 50%;
  background: var(--text-muted); transition: background 0.3s, box-shadow 0.3s;
}
.hand-status.detected { color: var(--success); border-color: rgba(16,185,129,0.4); background: rgba(16,185,129,0.08); }
.hand-status.detected::before {
  background: var(--success); box-shadow: 0 0 6px rgba(16,185,129,0.6);
  animation: dotPulse 1.2s ease-in-out infinite;
}
@keyframes dotPulse {
  0%,100% { transform: translateY(-50%) scale(1); }
  50%      { transform: translateY(-50%) scale(1.45); }
}

/* How-to trigger */
.how-to-trigger {
  position: absolute; top: 10px; right: 10px; z-index: 10;
  width: 30px; height: 30px; border-radius: 50%;
  background: rgba(11,25,41,0.8); backdrop-filter: blur(6px);
  border: 1px solid var(--border); color: var(--text-dim);
  cursor: pointer; display: flex; align-items: center; justify-content: center;
  transition: all 0.2s;
}
.how-to-trigger:hover { border-color: var(--teal); color: var(--teal-light); background: var(--teal-dim); }
.how-to-trigger svg { width: 15px; height: 15px; }

/* How-to panel */
.how-to-panel {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); overflow: hidden; flex-shrink: 0;
  animation: slideDown 0.2s ease-out;
}
@keyframes slideDown {
  from { opacity:0; transform:translateY(-6px); }
  to   { opacity:1; transform:translateY(0); }
}
.how-to-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 9px 13px; border-bottom: 1px solid var(--border); background: var(--surface2);
}
.how-to-title { font-size: 0.72rem; font-weight: 700; color: var(--teal-light); text-transform: uppercase; letter-spacing: 0.5px; }
.how-to-close { background: none; border: none; color: var(--text-dim); cursor: pointer; font-size: 0.78rem; padding: 2px 6px; border-radius: 4px; }
.how-to-close:hover { color: var(--text); }
.how-to-steps { list-style: none; padding: 10px 13px; display: flex; flex-direction: column; gap: 6px; counter-reset: steps; }
.how-to-steps li {
  display: flex; gap: 9px; font-size: 0.75rem; color: var(--text-dim);
  line-height: 1.4; counter-increment: steps;
}
.how-to-steps li::before {
  content: counter(steps);
  min-width: 18px; height: 18px;
  background: var(--teal-dim); border: 1px solid var(--teal-border); border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-size: 0.6rem; font-weight: 700; color: var(--teal-light); flex-shrink: 0; margin-top: 1px;
}
.how-to-steps li strong { color: var(--text); font-weight: 600; }

/* ── Below-video aux panels ── */
.video-aux {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 12px 14px;
  display: flex; flex-direction: column; gap: 8px;
  flex-shrink: 0;
}
.aux-label {
  font-size: 0.62rem; font-weight: 700; text-transform: uppercase;
  letter-spacing: 1.2px; color: var(--text-muted); text-align: center;
}
.aux-live-letter {
  font-size: 3.5rem; font-weight: 900; line-height: 1;
  color: var(--teal-light); text-align: center;
  text-shadow: 0 0 24px var(--teal-glow);
  transition: color 0.2s, text-shadow 0.2s;
  font-variant-numeric: tabular-nums;
}
.aux-live-letter.conf-high { color: var(--success); text-shadow: 0 0 24px rgba(16,185,129,0.5); }
.aux-live-letter.conf-med  { color: var(--warning); text-shadow: 0 0 24px rgba(245,158,11,0.5); }
.aux-live-letter.conf-low  { color: var(--danger);  text-shadow: 0 0 24px rgba(239,68,68,0.4); }
.aux-live-conf { font-size: 0.72rem; color: var(--text-dim); text-align: center; font-weight: 500; }

/* Perf row (recognize aux) */
.status-msg {
  text-align: center; padding: 7px 12px; border-radius: var(--radius-sm);
  font-size: 0.76rem; font-weight: 500;
}
.status-msg.loading { background: var(--warning-dim); color: var(--warning); border: 1px solid rgba(245,158,11,0.3); }
.status-msg.ready   { background: var(--success-dim); color: var(--success); border: 1px solid rgba(16,185,129,0.3); }
.status-msg.error   { background: var(--danger-dim);  color: var(--danger);  border: 1px solid rgba(239,68,68,0.3); }
.calibration-prompt {
  background: var(--warning-dim); border: 1px solid rgba(245,158,11,0.35);
  border-radius: var(--radius-sm); padding: 6px 10px;
  font-size: 0.72rem; color: var(--warning); text-align: center;
}
.perf-row { display: flex; justify-content: center; gap: 10px; }
.perf-chip {
  font-size: 0.7rem; color: var(--text-muted);
  background: var(--surface2); padding: 3px 9px;
  border-radius: 20px; border: 1px solid var(--border-dim);
  font-variant-numeric: tabular-nums;
}

/* ── RIGHT: Page column ── */
.page-column {
  min-height: calc(100vh - 58px);
  overflow-y: auto;
  padding: 16px 20px 20px 16px;
}
.page-content { display: flex; flex-direction: column; gap: 14px; }
.hidden { display: none !important; }

/* Page header (practice/learn) */
.page-header { padding: 4px 0 8px; border-bottom: 1px solid var(--border-dim); margin-bottom: 2px; }
.page-title { font-size: 1.2rem; font-weight: 800; color: var(--text); letter-spacing: -0.3px; }
.page-desc  { font-size: 0.78rem; color: var(--text-dim); margin-top: 3px; }

/* ══════════════════════════════════════════════
   CARD BASE
══════════════════════════════════════════════ */
.prediction-card,
.text-card,
.practice-main-card,
.practice-grid-card,
.practice-drill-card,
.learn-grid-card,
.learn-photo-card,
.learn-info-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
}
.card-label {
  font-size: 0.62rem; font-weight: 700; text-transform: uppercase;
  letter-spacing: 1.2px; color: var(--text-muted); margin-bottom: 10px;
}

/* ══════════════════════════════════════════════
   RECOGNIZE PAGE — Prediction Card
══════════════════════════════════════════════ */
.prediction-card { padding: 16px; }

.pred-top { display: flex; align-items: stretch; gap: 14px; margin-bottom: 14px; }

.pred-letter-section { display: flex; flex-direction: column; align-items: center; gap: 6px; flex-shrink: 0; }
.pred-label {
  font-size: 0.62rem; font-weight: 700; text-transform: uppercase;
  letter-spacing: 1.5px; color: var(--text-dim);
}
.letter-frame {
  width: 100px; height: 100px;
  background: var(--surface2); border: 1.5px solid var(--border);
  border-radius: var(--radius);
  display: flex; align-items: center; justify-content: center;
  position: relative; overflow: hidden;
  transition: border-color 0.25s, box-shadow 0.25s;
}
.letter-frame::before {
  content: ''; position: absolute; inset: 0;
  background: linear-gradient(135deg, var(--teal-dim) 0%, transparent 60%);
  opacity: 0; transition: opacity 0.3s;
}
.letter-frame.active { border-color: var(--teal); box-shadow: var(--shadow-teal); }
.letter-frame.active::before { opacity: 1; }

.predicted-letter {
  font-size: 4rem; font-weight: 900; line-height: 1;
  color: var(--text-dim); transition: color 0.2s, text-shadow 0.2s;
  position: relative; z-index: 1; letter-spacing: -2px;
}
.predicted-letter.conf-high { color: var(--success); text-shadow: 0 0 24px rgba(16,185,129,0.5); }
.predicted-letter.conf-med  { color: var(--warning); text-shadow: 0 0 24px rgba(245,158,11,0.5); }
.predicted-letter.conf-low  { color: var(--danger);  text-shadow: 0 0 24px rgba(239,68,68,0.4); }
.predicted-letter.flash { animation: letterPop 0.28s cubic-bezier(0.34,1.56,0.64,1) forwards; }
@keyframes letterPop {
  0%  { transform: scale(1); }
  45% { transform: scale(1.22); }
  100%{ transform: scale(1); }
}

.pred-stats-section {
  flex: 1; display: flex; flex-direction: column; justify-content: center;
  border-left: 1px solid var(--border); padding-left: 14px; gap: 0;
}
.session-stat {
  display: flex; align-items: baseline; justify-content: space-between;
  padding: 8px 0; border-bottom: 1px solid var(--border-dim);
}
.session-stat:last-child { border-bottom: none; }
.stat-value { font-size: 1.6rem; font-weight: 800; color: var(--teal-light); line-height: 1; font-variant-numeric: tabular-nums; }
.stat-label { font-size: 0.6rem; color: var(--text-muted); text-transform: uppercase; letter-spacing: 1.2px; font-weight: 600; }

.conf-section { display: flex; flex-direction: column; gap: 6px; }
.conf-header { display: flex; justify-content: space-between; align-items: center; }
.conf-label { font-size: 0.65rem; color: var(--text-dim); font-weight: 600; text-transform: uppercase; letter-spacing: 1px; }
.confidence-level { font-size: 0.65rem; font-weight: 700; text-transform: uppercase; letter-spacing: 1px; }
.confidence-level.conf-high { color: var(--success); }
.confidence-level.conf-med  { color: var(--warning); }
.confidence-level.conf-low  { color: var(--danger); }
.conf-bar-track { width: 100%; height: 10px; background: var(--surface2); border-radius: 5px; overflow: hidden; border: 1px solid var(--border-dim); }
.confidence-bar { height: 100%; width: 0%; border-radius: 5px; transition: width 0.2s ease, background 0.3s; }
.confidence-bar.conf-high { background: linear-gradient(90deg, var(--success), #34d399); }
.confidence-bar.conf-med  { background: linear-gradient(90deg, var(--warning), #fbbf24); }
.confidence-bar.conf-low  { background: linear-gradient(90deg, var(--danger), #f87171); }

/* ── Word Builder Card ── */
.text-card { padding: 14px; display: flex; flex-direction: column; gap: 12px; }
.text-label {
  font-size: 0.62rem; font-weight: 700; text-transform: uppercase;
  letter-spacing: 1.5px; color: var(--text-dim); margin-bottom: 5px;
}
.word-builder-section { border-bottom: 1px solid var(--border-dim); padding-bottom: 12px; }
.current-word-display {
  background: var(--surface2); border: 1px solid var(--teal-border);
  border-radius: var(--radius-sm); padding: 8px 14px; min-height: 46px;
  display: flex; align-items: center;
}
#current-word-letters {
  font-size: 1.6rem; font-weight: 800; letter-spacing: 5px;
  color: var(--teal-light); text-shadow: 0 0 20px rgba(34,211,238,0.3);
}
.suggestions-panel { display: flex; flex-wrap: wrap; gap: 5px; margin-top: 7px; min-height: 24px; }
.suggestion-btn {
  padding: 3px 11px; border: 1px solid var(--teal-border); border-radius: 20px;
  background: var(--teal-dim); color: var(--teal-light);
  cursor: pointer; font-size: 0.74rem; font-weight: 500; font-family: var(--font);
  transition: all 0.15s;
}
.suggestion-btn:hover { background: var(--teal); color: #fff; border-color: var(--teal); transform: translateY(-1px); }
.suggestion-btn.top-pick { background: rgba(14,116,144,0.3); border-color: var(--teal-light); color: #fff; font-weight: 700; }

.translated-text {
  background: var(--surface2); border: 1px solid var(--border);
  border-radius: var(--radius-sm); padding: 10px 14px; min-height: 52px;
  font-size: 1rem; letter-spacing: 1.5px; line-height: 1.5; word-break: break-all; color: var(--text);
}
.cursor { animation: blink 1s infinite; color: var(--teal-light); }
@keyframes blink { 0%,49%{opacity:1;} 50%,100%{opacity:0;} }
@keyframes sentenceFlash {
  0%   { background: rgba(14,116,144,0.18); border-color: var(--teal); }
  100% { background: var(--surface2); border-color: var(--border); }
}
.word-commit-flash { animation: sentenceFlash 0.4s ease-out forwards !important; }

.text-hint { font-size: 0.66rem; color: var(--text-muted); text-align: center; }
.text-controls { display: grid; grid-template-columns: repeat(4,1fr); gap: 6px; }
.ctrl-btn {
  display: flex; align-items: center; justify-content: center; gap: 5px;
  padding: 8px 4px; border: 1px solid var(--border); border-radius: var(--radius-sm);
  background: transparent; color: var(--text-dim);
  cursor: pointer; font-size: 0.7rem; font-weight: 500; font-family: var(--font);
  transition: all 0.18s; white-space: nowrap;
}
.ctrl-btn svg { width: 12px; height: 12px; flex-shrink: 0; }
.ctrl-btn:hover { border-color: var(--teal); color: var(--teal-light); background: var(--teal-dim); }
.ctrl-btn:active { transform: scale(0.96); }

/* ══════════════════════════════════════════════
   PRACTICE PAGE
══════════════════════════════════════════════ */
.practice-main-card { padding: 20px; }
.practice-header { display: flex; align-items: center; gap: 20px; margin-bottom: 12px; }
.practice-target-area { text-align: center; flex-shrink: 0; }
.practice-instruction { font-size: 0.62rem; font-weight: 700; color: var(--text-dim); text-transform: uppercase; letter-spacing: 1.5px; margin-bottom: 6px; }
.practice-target-letter { font-size: 5rem; font-weight: 900; color: var(--teal-light); text-shadow: 0 0 30px var(--teal-glow); line-height: 1.1; }
.practice-result {
  flex: 1; font-size: 0.88rem; font-weight: 700; min-height: 40px;
  text-align: center; padding: 10px 14px; border-radius: var(--radius-sm); transition: all 0.2s;
}
.practice-result small { font-weight: 400; color: var(--text-dim); }
.result-correct { color: var(--success); background: var(--success-dim); }
.result-wrong   { color: var(--danger);  background: var(--danger-dim); }
.practice-quality { text-align: center; font-size: 0.8rem; min-height: 20px; margin-top: 4px; }
.quality-high { color: var(--success); } .quality-med { color: var(--warning); } .quality-low { color: var(--danger); }
.practice-stats-row {
  display: flex; justify-content: space-between;
  font-size: 0.78rem; color: var(--text-dim);
  padding: 10px 0 0; border-top: 1px solid var(--border-dim); margin-top: 10px;
}

.practice-grid-card { padding: 16px; }
.practice-letter-grid { display: grid; grid-template-columns: repeat(13,1fr); gap: 4px; }
.practice-grid-cell {
  text-align: center; font-size: 0.62rem; font-weight: 600;
  padding: 5px 0; border-radius: 5px;
  background: var(--surface2); color: var(--text-muted); border: 1px solid transparent;
}
.practice-grid-cell.good { background: var(--success-dim); border-color: var(--success); color: var(--success); }
.practice-grid-cell.ok   { background: var(--warning-dim); border-color: var(--warning); color: var(--warning); }
.practice-grid-cell.bad  { background: var(--danger-dim);  border-color: var(--danger);  color: var(--danger); }

.practice-drill-card { padding: 16px; }
.practice-controls { display: flex; gap: 8px; flex-wrap: wrap; }
.practice-btn {
  flex: 1; min-width: 100px; padding: 9px 8px;
  border: 1px solid var(--border); border-radius: var(--radius-sm);
  background: transparent; color: var(--text-dim);
  cursor: pointer; font-size: 0.75rem; font-weight: 600; font-family: var(--font);
  transition: all 0.18s;
}
.practice-btn:hover { border-color: var(--teal); color: var(--teal-light); background: var(--teal-dim); }
.reset-btn:hover { border-color: var(--danger); color: var(--danger); background: var(--danger-dim); }

/* ══════════════════════════════════════════════
   SPEED CONTROL & COMMIT PROGRESS
══════════════════════════════════════════════ */
.speed-control {
  margin-top: 8px; padding: 10px 12px;
  background: var(--surface2); border: 1px solid var(--border-dim);
  border-radius: var(--radius-sm);
}
.speed-header {
  display: flex; align-items: center; justify-content: space-between; margin-bottom: 8px;
}
.speed-indicator {
  font-size: 0.68rem; font-weight: 700; color: var(--teal-light);
  padding: 2px 10px; background: var(--teal-dim); border-radius: 12px;
  border: 1px solid var(--teal-border);
}
.speed-btns { display: flex; gap: 6px; margin-bottom: 10px; }
.speed-btn {
  flex: 1; padding: 8px 12px; border: 1px solid var(--border);
  border-radius: var(--radius-sm); background: transparent;
  color: var(--text-muted); cursor: pointer; font-size: 0.76rem;
  font-weight: 600; font-family: var(--font); transition: all 0.2s;
  min-height: 38px;
}
.speed-btn:hover { border-color: var(--teal); color: var(--teal-light); background: var(--teal-dim); }
.speed-btn.active {
  background: var(--teal-dim); border-color: var(--teal);
  color: var(--teal-light); font-weight: 700;
  box-shadow: 0 0 8px var(--teal-glow);
}
.commit-progress-wrap {
  display: flex; align-items: center; gap: 8px;
}
.commit-progress-track {
  flex: 1; height: 6px; background: var(--bg);
  border-radius: 3px; overflow: hidden;
  border: 1px solid var(--border-dim);
}
.commit-progress-bar {
  height: 100%; width: 0%;
  background: linear-gradient(90deg, var(--teal), var(--teal-light));
  border-radius: 3px; transition: width 0.1s linear;
}
.commit-progress-label {
  font-size: 0.68rem; font-weight: 700; color: var(--teal-light);
  min-width: 60px; text-align: right;
}

/* ══════════════════════════════════════════════
   LEARN PAGE
══════════════════════════════════════════════ */

/* ── Learn cards base ── */
.learn-header-card, .learn-visual-card, .learn-detail-card,
.lesson-card, .quiz-card, .fc-card-wrap, .learn-stats-card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-lg); box-shadow: var(--shadow);
}

/* ── Learn header ── */
.learn-header-card { padding: 16px 18px 0; }
.learn-header-top { display: flex; align-items: center; justify-content: space-between; margin-bottom: 14px; }
.learn-ring-wrap { position: relative; width: 64px; height: 64px; flex-shrink: 0; }
.learn-ring-svg { width: 100%; height: 100%; }
.learn-ring-pct {
  position: absolute; inset: 0; display: flex; align-items: center; justify-content: center;
  font-size: 0.72rem; font-weight: 800; color: var(--teal-light);
}
#learn-ring-fill { transition: stroke-dashoffset 0.6s ease; }

/* ── Learn mode tabs ── */
.learn-mode-tabs {
  display: flex; gap: 2px; border-top: 1px solid var(--border-dim);
  margin: 0 -18px; padding: 0;
}
.learn-tab {
  flex: 1; display: flex; align-items: center; justify-content: center; gap: 5px;
  padding: 10px 6px; border: none; border-bottom: 2px solid transparent;
  background: transparent; color: var(--text-muted); cursor: pointer;
  font-size: 0.72rem; font-weight: 600; font-family: var(--font);
  transition: all 0.2s; white-space: nowrap;
}
.learn-tab svg { width: 14px; height: 14px; flex-shrink: 0; }
.learn-tab:hover { color: var(--text-dim); background: rgba(255,255,255,0.02); }
.learn-tab.active { color: var(--teal-light); border-bottom-color: var(--teal-light); background: var(--teal-dim); }

/* ── Alphabet grid ── */
.learn-grid-card { padding: 14px 16px; background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius-lg); box-shadow: var(--shadow); }
.learn-grid-top { display: flex; align-items: center; justify-content: space-between; margin-bottom: 10px; }
.learn-legend { display: flex; gap: 10px; align-items: center; }
.lg-item { display: flex; align-items: center; gap: 3px; font-size: 0.58rem; color: var(--text-muted); font-weight: 500; }
.lg-dot { width: 8px; height: 8px; border-radius: 50%; }
.lg-new { background: var(--surface2); border: 1px solid var(--border); }
.lg-seen { background: rgba(96,165,250,0.2); border: 1px solid rgba(96,165,250,0.5); }
.lg-practiced { background: rgba(245,158,11,0.2); border: 1px solid rgba(245,158,11,0.5); }
.lg-mastered { background: rgba(16,185,129,0.2); border: 1px solid rgba(16,185,129,0.5); }
.learn-letter-grid { display: grid; grid-template-columns: repeat(13,1fr); gap: 4px; margin-bottom: 8px; }
.learn-grid-cell {
  text-align: center; font-size: 0.68rem; font-weight: 700;
  padding: 6px 0; border-radius: 6px;
  background: var(--surface2); color: var(--text-muted); border: 1px solid transparent;
  cursor: pointer; transition: all 0.15s; position: relative;
}
.learn-grid-cell:hover { border-color: var(--teal); color: var(--teal-light); }
.learn-grid-cell.active { background: var(--teal-dim); border-color: var(--teal); color: var(--teal-light); font-weight: 800; }
.learn-grid-cell.mastery-seen { background: rgba(96,165,250,0.1); border-color: rgba(96,165,250,0.3); color: #93bbfd; }
.learn-grid-cell.mastery-practiced { background: rgba(245,158,11,0.1); border-color: rgba(245,158,11,0.35); color: #fbbf24; }
.learn-grid-cell.mastery-mastered { background: rgba(16,185,129,0.12); border-color: rgba(16,185,129,0.4); color: #6ee7b7; }
.learn-grid-cell.active.mastery-seen,
.learn-grid-cell.active.mastery-practiced,
.learn-grid-cell.active.mastery-mastered { background: var(--teal-dim); border-color: var(--teal); color: var(--teal-light); }
.learn-progress-text { font-size: 0.68rem; color: var(--text-muted); text-align: right; }

/* ── Browse view ── */
.learn-view { display: flex; flex-direction: column; gap: 14px; }
.learn-browse-row { display: grid; grid-template-columns: auto 1fr; gap: 14px; align-items: start; }
.learn-visual-card { padding: 14px; display: flex; flex-direction: column; align-items: center; gap: 10px; }
.learn-ref-img {
  width: 220px; height: auto; max-height: 280px;
  border-radius: 12px; border: 2px solid var(--border);
  background: #fff;
  object-fit: contain; padding: 14px;
  transition: opacity 0.3s;
  box-shadow: 0 2px 12px rgba(0,0,0,0.15);
}
.learn-ref-img[src=""] { opacity: 0; height: 0; padding: 0; border: none; }
.lesson-ref-img { width: 200px; }
.quiz-ref-img { width: 200px; max-height: 260px; margin: 0 auto; }
.fc-ref-img { width: 180px; max-height: 220px; }

.learn-detail-card { padding: 16px; display: flex; flex-direction: column; gap: 12px; }
.learn-detail-top { display: flex; align-items: flex-start; justify-content: space-between; gap: 12px; }
.learn-letter-huge {
  font-size: 4.2rem; font-weight: 900; line-height: 1;
  color: var(--teal-light); text-shadow: 0 0 28px var(--teal-glow);
}
.learn-badges { display: flex; flex-direction: column; gap: 4px; align-items: flex-end; padding-top: 4px; }
.learn-badge {
  padding: 3px 10px; border-radius: 20px; font-size: 0.6rem; font-weight: 700;
  text-transform: uppercase; letter-spacing: 0.5px; white-space: nowrap;
}
.learn-badge.diff { background: rgba(96,165,250,0.15); color: #93bbfd; border: 1px solid rgba(96,165,250,0.3); }
.learn-badge.diff.intermediate { background: rgba(245,158,11,0.15); color: #fbbf24; border-color: rgba(245,158,11,0.3); }
.learn-badge.diff.advanced { background: rgba(239,68,68,0.15); color: #f87171; border-color: rgba(239,68,68,0.3); }
.learn-badge.mast { background: var(--surface2); color: var(--text-muted); border: 1px solid var(--border); }
.learn-badge.mast.seen { background: rgba(96,165,250,0.15); color: #93bbfd; border-color: rgba(96,165,250,0.3); }
.learn-badge.mast.practiced { background: rgba(245,158,11,0.15); color: #fbbf24; border-color: rgba(245,158,11,0.3); }
.learn-badge.mast.mastered { background: rgba(16,185,129,0.15); color: #6ee7b7; border-color: rgba(16,185,129,0.35); }

.learn-steps-box { display: flex; flex-direction: column; gap: 6px; }
.learn-section-label {
  font-size: 0.6rem; font-weight: 700; text-transform: uppercase;
  letter-spacing: 1.2px; color: var(--text-muted);
}
.learn-step-list {
  list-style: none; counter-reset: steps; display: flex; flex-direction: column; gap: 5px;
  padding: 0; margin: 0;
}
.learn-step-list li {
  display: flex; gap: 8px; font-size: 0.78rem; color: var(--text);
  line-height: 1.4; counter-increment: steps; align-items: flex-start;
}
.learn-step-list li::before {
  content: counter(steps);
  min-width: 20px; height: 20px; flex-shrink: 0;
  background: var(--teal-dim); border: 1px solid var(--teal-border); border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-size: 0.58rem; font-weight: 700; color: var(--teal-light); margin-top: 1px;
}
.learn-mnemonic-box {
  background: var(--teal-dim); border: 1px solid var(--teal-border);
  border-left: 3px solid var(--teal); border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  padding: 7px 10px; font-size: 0.76rem; color: var(--teal-light);
  font-style: italic; line-height: 1.45;
}
.learn-mnemonic-box:empty { display: none; }
.learn-similar-box { font-size: 0.74rem; color: var(--text-dim); line-height: 1.5; }
.learn-similar-box:empty { display: none; }
.learn-similar-box .sim-tag {
  display: inline-block; padding: 1px 7px; border-radius: 4px; margin: 0 2px;
  background: rgba(239,68,68,0.12); color: #f87171; font-weight: 700; font-size: 0.72rem;
  border: 1px solid rgba(239,68,68,0.25);
}

/* Try-it section */
.learn-tryit-box {
  background: var(--surface2); border: 1px solid var(--border);
  border-radius: var(--radius-sm); padding: 10px 12px;
  display: flex; flex-direction: column; gap: 6px;
}
.learn-tryit-msg { font-size: 0.76rem; color: var(--text-dim); text-align: center; min-height: 20px; transition: all 0.2s; }
.learn-tryit-msg.success { color: var(--success); font-weight: 700; }
.learn-tryit-msg.holding { color: var(--teal-light); }
.learn-tryit-bar-wrap { display: flex; align-items: center; gap: 8px; }
.learn-tryit-bar-track { flex: 1; height: 6px; background: var(--bg); border-radius: 3px; overflow: hidden; }
.learn-tryit-bar-fill { height: 100%; width: 0%; background: linear-gradient(90deg, var(--teal), var(--teal-light)); border-radius: 3px; transition: width 0.1s linear; }
.learn-tryit-pct { font-size: 0.62rem; color: var(--text-muted); font-weight: 600; min-width: 28px; text-align: right; }

.learn-detail-nav { display: flex; gap: 6px; }
.learn-nav-btn {
  padding: 8px 14px; border: 1px solid var(--border);
  border-radius: var(--radius-sm); background: transparent;
  color: var(--text-dim); cursor: pointer; font-size: 0.78rem; font-family: var(--font);
  transition: all 0.18s;
}
.learn-nav-btn:hover { border-color: var(--teal); color: var(--teal-light); background: var(--teal-dim); }
.learn-practice-btn {
  flex: 1; padding: 8px 14px; border: none;
  border-radius: var(--radius-sm); background: var(--success);
  color: #fff; cursor: pointer; font-size: 0.78rem; font-weight: 700; font-family: var(--font);
  transition: all 0.18s;
}
.learn-practice-btn:hover { filter: brightness(1.1); transform: translateY(-1px); }

/* ── Lesson view ── */
.lesson-card { padding: 18px; }
.lesson-top-row { display: flex; align-items: center; gap: 12px; margin-bottom: 14px; }
.lesson-step-label { font-size: 0.72rem; font-weight: 700; color: var(--teal-light); white-space: nowrap; }
.lesson-bar-track { flex: 1; height: 6px; background: var(--surface2); border-radius: 3px; overflow: hidden; }
.lesson-bar-fill { height: 100%; width: 0%; background: linear-gradient(90deg, var(--teal), var(--success)); border-radius: 3px; transition: width 0.4s ease; }
.lesson-body { display: grid; grid-template-columns: auto 1fr; gap: 16px; align-items: start; margin-bottom: 14px; }
.lesson-visual-col { display: flex; flex-direction: column; align-items: center; gap: 8px; }
.lesson-target-letter {
  font-size: 4rem; font-weight: 900; color: var(--teal-light);
  text-shadow: 0 0 28px var(--teal-glow); line-height: 1; text-align: center;
}
.lesson-info-col { display: flex; flex-direction: column; gap: 10px; }
.lesson-desc { font-size: 0.82rem; color: var(--text); line-height: 1.6; }
.lesson-steps { font-size: 0.76rem; color: var(--text-dim); line-height: 1.5; }
.lesson-steps ol { margin: 4px 0 0 16px; padding: 0; }
.lesson-steps li { margin-bottom: 3px; }
.lesson-feedback {
  padding: 8px 12px; border-radius: var(--radius-sm); font-size: 0.78rem; font-weight: 600;
  text-align: center; min-height: 36px; display: flex; align-items: center; justify-content: center;
  background: var(--surface2); color: var(--text-dim); border: 1px solid var(--border);
  transition: all 0.2s;
}
.lesson-feedback.correct { background: var(--success-dim); color: var(--success); border-color: rgba(16,185,129,0.4); }
.lesson-feedback.holding { background: var(--teal-dim); color: var(--teal-light); border-color: var(--teal-border); }
.lesson-hold-wrap { display: flex; align-items: center; gap: 8px; }
.lesson-hold-track { flex: 1; height: 8px; background: var(--surface2); border-radius: 4px; overflow: hidden; border: 1px solid var(--border-dim); }
.lesson-hold-bar { height: 100%; width: 0%; background: linear-gradient(90deg, var(--teal), var(--teal-light)); border-radius: 4px; transition: width 0.1s linear; }
.lesson-controls { display: flex; gap: 8px; }
.lesson-btn {
  flex: 1; padding: 9px 8px; border: 1px solid var(--border);
  border-radius: var(--radius-sm); background: transparent;
  color: var(--text-dim); cursor: pointer; font-size: 0.78rem; font-weight: 600; font-family: var(--font);
  transition: all 0.18s; text-align: center;
}
.lesson-btn:hover { border-color: var(--teal); color: var(--teal-light); background: var(--teal-dim); }
.lesson-btn.primary { background: var(--teal); color: #fff; border-color: var(--teal); font-weight: 700; }
.lesson-btn.primary:hover { background: #0e8fad; }
.lesson-btn.primary.stop { background: var(--danger); border-color: var(--danger); }

/* ── Quiz view ── */
.quiz-card { padding: 18px; }
.quiz-top-row { display: flex; align-items: center; justify-content: space-between; gap: 12px; margin-bottom: 14px; flex-wrap: wrap; }
.quiz-type-tabs { display: flex; gap: 4px; }
.quiz-type-btn {
  padding: 6px 14px; border: 1px solid var(--border); border-radius: 20px;
  background: transparent; color: var(--text-muted); cursor: pointer;
  font-size: 0.72rem; font-weight: 600; font-family: var(--font); transition: all 0.18s;
}
.quiz-type-btn:hover { border-color: var(--teal); color: var(--teal-light); }
.quiz-type-btn.active { background: var(--teal-dim); border-color: var(--teal); color: var(--teal-light); }
.quiz-score-area { display: flex; align-items: center; gap: 10px; }
.quiz-score { font-size: 0.88rem; font-weight: 800; color: var(--text); }
.quiz-streak { font-size: 0.78rem; font-weight: 700; color: var(--warning); }
.quiz-body { display: flex; flex-direction: column; align-items: center; gap: 14px; min-height: 200px; justify-content: center; }
.quiz-prompt { font-size: 1rem; font-weight: 600; color: var(--text); text-align: center; line-height: 1.5; }
.quiz-letter-big { font-size: 5rem; font-weight: 900; color: var(--teal-light); text-shadow: 0 0 30px var(--teal-glow); line-height: 1; }
.quiz-options { display: grid; grid-template-columns: repeat(2,1fr); gap: 8px; width: 100%; max-width: 400px; }
.quiz-opt-btn {
  padding: 12px 8px; border: 1px solid var(--border); border-radius: var(--radius-sm);
  background: var(--surface2); color: var(--text); cursor: pointer;
  font-size: 1.2rem; font-weight: 800; font-family: var(--font);
  transition: all 0.18s; text-align: center;
}
.quiz-opt-btn:hover { border-color: var(--teal); background: var(--teal-dim); color: var(--teal-light); transform: translateY(-1px); }
.quiz-opt-btn.correct { background: var(--success-dim); border-color: var(--success); color: var(--success); }
.quiz-opt-btn.wrong { background: var(--danger-dim); border-color: var(--danger); color: var(--danger); }
.quiz-opt-btn:disabled { cursor: default; transform: none; }
.quiz-timer-wrap { width: 100%; max-width: 400px; display: flex; align-items: center; gap: 8px; }
.quiz-timer-track { flex: 1; height: 8px; background: var(--surface2); border-radius: 4px; overflow: hidden; }
.quiz-timer-fill { height: 100%; width: 100%; background: linear-gradient(90deg, var(--danger), var(--warning), var(--success)); border-radius: 4px; transition: width 0.5s linear; }
.quiz-timer-text { font-size: 0.72rem; font-weight: 700; color: var(--text-dim); min-width: 30px; text-align: right; }
.quiz-feedback {
  min-height: 36px; padding: 8px 12px; border-radius: var(--radius-sm);
  font-size: 0.82rem; font-weight: 700; text-align: center; transition: all 0.2s;
}
.quiz-feedback.correct { background: var(--success-dim); color: var(--success); }
.quiz-feedback.wrong { background: var(--danger-dim); color: var(--danger); }
.quiz-result {
  padding: 16px; border-radius: var(--radius); background: var(--surface2); border: 1px solid var(--border);
  text-align: center;
}
.quiz-result h3 { font-size: 1.1rem; color: var(--teal-light); margin-bottom: 8px; }
.quiz-result .qr-stat { font-size: 0.82rem; color: var(--text-dim); margin: 4px 0; }
.quiz-result .qr-stat strong { color: var(--text); }
.quiz-result button {
  margin-top: 10px; padding: 8px 20px; border: none; border-radius: var(--radius-sm);
  background: var(--teal); color: #fff; cursor: pointer; font-weight: 700; font-family: var(--font);
}

/* ── Flashcard view ── */
.fc-card-wrap { padding: 18px; }
.fc-top-row { display: flex; align-items: center; justify-content: space-between; margin-bottom: 14px; flex-wrap: wrap; gap: 8px; }
.fc-counter { font-size: 0.78rem; font-weight: 700; color: var(--text-dim); }
.fc-filter-tabs { display: flex; gap: 4px; }
.fc-filter-btn {
  padding: 5px 12px; border: 1px solid var(--border); border-radius: 20px;
  background: transparent; color: var(--text-muted); cursor: pointer;
  font-size: 0.68rem; font-weight: 600; font-family: var(--font); transition: all 0.18s;
}
.fc-filter-btn:hover { border-color: var(--teal); color: var(--teal-light); }
.fc-filter-btn.active { background: var(--teal-dim); border-color: var(--teal); color: var(--teal-light); }
.fc-area { display: flex; justify-content: center; margin-bottom: 14px; perspective: 800px; }
.fc-card {
  width: 260px; min-height: 320px; cursor: pointer; position: relative;
  transform-style: preserve-3d; transition: transform 0.5s ease;
}
.fc-card.flipped { transform: rotateY(180deg); }
.fc-front, .fc-back {
  position: absolute; inset: 0; backface-visibility: hidden;
  border-radius: var(--radius-lg); border: 1.5px solid var(--border);
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  padding: 20px;
}
.fc-front {
  background: linear-gradient(135deg, var(--surface2), var(--surface));
  z-index: 2;
}
.fc-back {
  background: var(--surface); transform: rotateY(180deg);
  gap: 10px; justify-content: flex-start; padding-top: 14px;
}
.fc-front-letter { font-size: 7rem; font-weight: 900; color: var(--teal-light); text-shadow: 0 0 40px var(--teal-glow); line-height: 1; }
.fc-front-hint { font-size: 0.68rem; color: var(--text-muted); margin-top: 12px; }
.fc-back-desc { font-size: 0.78rem; color: var(--text); line-height: 1.5; text-align: center; }
.fc-controls { display: flex; gap: 6px; }
.fc-btn {
  flex: 1; padding: 9px 8px; border: 1px solid var(--border);
  border-radius: var(--radius-sm); background: transparent; color: var(--text-dim);
  cursor: pointer; font-size: 0.78rem; font-weight: 600; font-family: var(--font);
  transition: all 0.18s; text-align: center;
}
.fc-btn:hover { border-color: var(--teal); color: var(--teal-light); background: var(--teal-dim); }
.fc-btn.fc-know { border-color: rgba(16,185,129,0.4); color: var(--success); }
.fc-btn.fc-know:hover { background: var(--success-dim); }
.fc-btn.fc-dunno { border-color: rgba(245,158,11,0.4); color: var(--warning); }
.fc-btn.fc-dunno:hover { background: var(--warning-dim); }

/* ── Stats dashboard ── */
.learn-stats-card { padding: 16px; background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius-lg); box-shadow: var(--shadow); }
.learn-stats-row { display: grid; grid-template-columns: repeat(4,1fr); gap: 10px; margin: 10px 0; }
.learn-stat-box { text-align: center; padding: 10px 4px; background: var(--surface2); border-radius: var(--radius-sm); border: 1px solid var(--border-dim); }
.learn-stat-val { font-size: 1.4rem; font-weight: 800; color: var(--teal-light); line-height: 1.2; }
.learn-stat-unit { font-size: 0.72rem; font-weight: 600; color: var(--text-muted); }
.learn-stat-lbl { font-size: 0.58rem; font-weight: 700; color: var(--text-muted); text-transform: uppercase; letter-spacing: 0.8px; margin-top: 4px; }
.learn-reset-btn {
  width: 100%; padding: 7px; border: 1px solid rgba(239,68,68,0.3);
  border-radius: var(--radius-sm); background: transparent;
  color: var(--text-muted); cursor: pointer; font-size: 0.7rem; font-weight: 500; font-family: var(--font);
  transition: all 0.18s;
}
.learn-reset-btn:hover { border-color: var(--danger); color: var(--danger); background: var(--danger-dim); }

/* ── Learn aux (below video) ── */
.learn-match-display {
  font-size: 0.76rem; font-weight: 700; min-height: 20px;
  border-radius: 20px; padding: 3px 12px; text-align: center; transition: all 0.2s;
}
.learn-match-display.match-correct { background: var(--success-dim); color: var(--success); border: 1px solid rgba(16,185,129,0.4); }
.learn-match-display.match-holding { background: var(--teal-dim); color: var(--teal-light); border: 1px solid var(--teal-border); }
.learn-match-display.match-wrong   { color: var(--text-muted); }
.learn-hold-wrap { display: flex; align-items: center; gap: 8px; }
.learn-hold-track { flex: 1; height: 6px; background: var(--surface2); border-radius: 3px; overflow: hidden; border: 1px solid var(--border-dim); }
.learn-hold-bar { height: 100%; width: 0%; background: linear-gradient(90deg, var(--teal), var(--teal-light)); border-radius: 3px; transition: width 0.1s linear; }
.learn-hold-label { font-size: 0.58rem; color: var(--text-muted); white-space: nowrap; font-weight: 500; }

/* ── Learn responsive ── */
@media (max-width: 768px) {
  .learn-browse-row { grid-template-columns: 1fr; }
  .learn-mode-tabs { overflow-x: auto; -webkit-overflow-scrolling: touch; }
  .learn-tab svg { display: none; }
  .lesson-body { grid-template-columns: 1fr; }
  .learn-stats-row { grid-template-columns: repeat(2,1fr); }
  .fc-card { width: 220px; min-height: 280px; }
  .learn-legend { display: none; }
  .learn-ref-img { width: 100%; max-width: 200px; }
  .quiz-options { grid-template-columns: repeat(2,1fr); }
  .learn-visual-card { padding: 10px; }
  .learn-detail-card { padding: 12px; }
  .learn-letter-huge { font-size: 3rem; }
}

/* ══════════════════════════════════════════════
   FOOTER
══════════════════════════════════════════════ */
footer {
  border-top: 1px solid var(--border-dim);
  background: rgba(10,20,33,0.98); padding: 12px 20px;
  position: relative; z-index: 1;
}
.footer-inner {
  max-width: 1400px; margin: 0 auto;
  display: flex; align-items: center; justify-content: center;
  flex-wrap: wrap; gap: 6px;
  font-size: 0.67rem; color: var(--text-muted);
}
.footer-logo { font-weight: 700; color: var(--teal-light); }
.footer-sep { color: var(--border); user-select: none; }

/* ══════════════════════════════════════════════
   HIDDEN COLLECT PANEL (JS compat)
══════════════════════════════════════════════ */
.collect-progress { display: grid; grid-template-columns: repeat(13,1fr); gap: 3px; margin-bottom: 12px; }
.letter-count { text-align: center; font-size: 0.62rem; padding: 3px 0; border-radius: 4px; background: var(--surface2); color: var(--text-dim); border: 1px solid transparent; }
.letter-count.has-data { border-color: var(--teal); color: var(--teal-light); }
.letter-count.enough { background: var(--success-dim); border-color: var(--success); color: var(--success); }
.btn-train { width: 100%; padding: 10px; border: none; border-radius: var(--radius-sm); background: var(--success); color: #fff; font-weight: 700; font-size: 0.88rem; cursor: pointer; }
.btn-train:disabled { opacity: 0.4; cursor: not-allowed; }

/* ══════════════════════════════════════════════
   RESPONSIVE — tablet (≤ 1024px)
══════════════════════════════════════════════ */
@media (max-width: 1024px) {
  .app-shell { grid-template-columns: 340px 1fr; }
}

/* ══════════════════════════════════════════════
   RESPONSIVE — mobile (≤ 768px)
══════════════════════════════════════════════ */
@media (max-width: 768px) {
  .app-shell { grid-template-columns: 1fr !important; }
  .video-column {
    position: static !important; height: auto !important;
    padding: 10px 10px 0;
    border-right: none; border-bottom: 1px solid var(--border);
    max-height: 50vh;
  }
  .video-container { border-radius: 10px; }
  .page-column { padding: 10px 10px 16px; min-height: auto; }
  .nav-pages { gap: 2px; }
  .nav-page-btn { padding: 8px 10px; font-size: 0.74rem; min-height: 40px; }
  .nav-page-btn svg { display: none; }
  .nav-sub { display: none; }
  .nav-badge { display: none; }
  .learn-content-row { grid-template-columns: 1fr; }
  .learn-ref-photo { width: 100%; height: 200px; }
  .text-controls { grid-template-columns: repeat(2,1fr); }
  .ctrl-btn { min-height: 44px; font-size: 0.76rem; }
  .practice-target-letter { font-size: 4rem; }
  .prediction-card { padding: 12px; }
  .text-card { padding: 12px; }
  .speed-btns { gap: 6px; }
  .speed-btn { min-height: 44px; font-size: 0.82rem; }
  .learn-letter-grid { grid-template-columns: repeat(9,1fr); gap: 3px; }
  .learn-grid-cell { padding: 8px 0; font-size: 0.72rem; min-height: 36px; }
  .fc-controls { flex-wrap: wrap; }
  .fc-btn { min-height: 44px; font-size: 0.82rem; }
  .quiz-opt-btn { min-height: 50px; padding: 14px 8px; font-size: 1.3rem; }
  .lesson-btn { min-height: 44px; }
  .learn-nav-btn, .learn-practice-btn { min-height: 44px; }
  .practice-btn { min-height: 44px; }
}

/* ══════════════════════════════════════════════
   RESPONSIVE — iPhone (≤ 480px)
══════════════════════════════════════════════ */
@media (max-width: 480px) {
  html { font-size: 15px; }
  .nav-inner { height: 50px; padding: 0 10px; }
  .nav-title { font-size: 0.72rem; }
  .nav-icon-wrap { width: 26px; height: 26px; }
  .nav-hand-icon { width: 13px; height: 13px; }
  .nav-pages { gap: 1px; overflow-x: auto; -webkit-overflow-scrolling: touch; flex-wrap: nowrap; }
  .nav-page-btn { padding: 6px 8px; font-size: 0.66rem; white-space: nowrap; min-height: 38px; flex-shrink: 0; }
  .model-chip { font-size: 0.58rem; padding: 2px 6px; }
  .aux-live-letter { font-size: 2.6rem; }
  .practice-target-letter { font-size: 3.2rem; }
  .learn-letter-huge { font-size: 2.6rem; }
  .letter-frame { width: 80px; height: 80px; }
  .predicted-letter { font-size: 3rem; }
  .video-column { padding: 8px 8px 0; }
  .page-column { padding: 8px 8px 14px; }

  /* Word builder on iPhone */
  .current-word-display { font-size: 1.4rem; min-height: 44px; }
  .text-controls { grid-template-columns: repeat(2,1fr); gap: 4px; }
  .ctrl-btn { font-size: 0.72rem; padding: 8px 6px; min-height: 44px; }
  .speed-btns { flex-direction: row; }
  .speed-btn { font-size: 0.76rem; min-height: 44px; }
  .commit-progress-label { min-width: 48px; font-size: 0.62rem; }

  /* Learn mode on iPhone */
  .learn-letter-grid { grid-template-columns: repeat(7,1fr); gap: 3px; }
  .learn-grid-cell { padding: 7px 0; font-size: 0.68rem; min-height: 34px; border-radius: 5px; }
  .learn-mode-tabs { margin: 0 -12px; }
  .learn-tab { padding: 10px 4px; font-size: 0.66rem; min-height: 40px; }
  .learn-header-card { padding: 12px 12px 0; }
  .learn-grid-card { padding: 10px 12px; }
  .learn-ref-img { width: 100%; max-width: 180px; padding: 10px; }
  .learn-visual-card { padding: 8px; }
  .learn-detail-card { padding: 10px; gap: 10px; }
  .learn-step-list li { font-size: 0.74rem; }
  .learn-detail-nav { flex-wrap: wrap; }
  .learn-nav-btn { flex: 1; min-height: 44px; }
  .learn-practice-btn { flex-basis: 100%; min-height: 44px; }
  .learn-browse-row { gap: 10px; }

  /* Flashcard on iPhone */
  .fc-card { width: 200px; min-height: 260px; }
  .fc-front-letter { font-size: 5rem; }
  .fc-ref-img { width: 150px; max-height: 180px; }
  .fc-controls { gap: 4px; flex-wrap: wrap; }
  .fc-btn { min-height: 44px; padding: 10px 6px; font-size: 0.74rem; }
  .fc-filter-tabs { gap: 3px; }
  .fc-filter-btn { padding: 6px 10px; font-size: 0.64rem; min-height: 32px; }

  /* Quiz on iPhone */
  .quiz-letter-big { font-size: 4rem; }
  .quiz-ref-img { width: 160px; max-height: 200px; }
  .quiz-opt-btn { min-height: 52px; padding: 14px 6px; font-size: 1.2rem; }
  .quiz-type-tabs { gap: 3px; }
  .quiz-type-btn { padding: 6px 10px; font-size: 0.66rem; min-height: 34px; }

  /* Lesson on iPhone */
  .lesson-card { padding: 12px; }
  .lesson-target-letter { font-size: 3rem; }
  .lesson-ref-img { width: 100%; max-width: 160px; }
  .lesson-controls { flex-wrap: wrap; }
  .lesson-btn { min-height: 44px; }

  /* Practice on iPhone */
  .practice-main-card { padding: 12px; }
  .practice-letter-grid { grid-template-columns: repeat(7,1fr); }
  .practice-btn { min-height: 44px; font-size: 0.76rem; }

  /* Stats on iPhone */
  .learn-stats-row { grid-template-columns: repeat(2,1fr); gap: 6px; }
  .learn-stat-val { font-size: 1.1rem; }
  .learn-stat-box { padding: 8px 4px; }

  /* Suggestions on iPhone */
  .suggestions-panel { gap: 3px; }
  .suggestion-chip { padding: 6px 10px; font-size: 0.72rem; min-height: 32px; }
}

/* ── Numbers Mode ── */
.numbers-subnav {
  display: flex;
  gap: 6px;
  padding: 6px;
  background: var(--surface);
  border-radius: var(--radius);
  margin-bottom: 16px;
  border: 1px solid var(--border);
}
.numbers-subnav-btn {
  flex: 1;
  padding: 10px 12px;
  border: none;
  border-radius: var(--radius-sm);
  background: transparent;
  color: var(--text-dim);
  font-family: var(--font);
  font-weight: 600;
  font-size: 0.85rem;
  cursor: pointer;
  transition: all 0.2s;
}
.numbers-subnav-btn:hover { background: var(--surface2); color: var(--text); }
.numbers-subnav-btn.active {
  background: var(--teal-dim);
  color: var(--teal-light);
  box-shadow: inset 0 0 0 1px var(--teal-border);
}
.numbers-view { /* default visible */ }
.num-grid { grid-template-columns: repeat(5, 1fr) !important; }
.num-learn-grid { grid-template-columns: repeat(5, 1fr) !important; }

/* Safe area (iPhone notch) */
@supports (padding: max(0px)) {
  .navbar { padding-left: max(20px, env(safe-area-inset-left)); padding-right: max(20px, env(safe-area-inset-right)); }
  .video-column { padding-left: max(20px, env(safe-area-inset-left)); }
  .page-column  { padding-right: max(20px, env(safe-area-inset-right)); }
  footer { padding-bottom: max(12px, env(safe-area-inset-bottom)); }
}