:root {
  --bg-canvas: #f7f4ee;
  --bg-surface: #ffffff;
  --bg-surface-alt: #faf8f3;
  --accent-forest: #184a3b;
  --accent-forest-hover: #12382c;
  --accent-tint: #eaf3ee;
  --text-primary: #1d231f;
  --text-secondary: #48544c;
  --text-muted: #637068;
  --border-hairline: #eaeaea;
  --border-medium: #d1c8b4;
  --danger-text: #8a1f1f;
  --danger-bg: #fdf3f3;
  --danger-border: #e6b8b8;
  --font-serif: Georgia, "Times New Roman", serif;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  --font-mono: "SF Mono", Menlo, Monaco, Consolas, monospace;
}

*, *::before, *::after { box-sizing: border-box; }
body {
  margin: 0;
  min-height: 100vh;
  background: var(--bg-canvas);
  color: var(--text-primary);
  font-family: var(--font-sans);
  line-height: 1.6;
}
h1, h2, h3, h4, p, ol, ul { margin: 0; }
button, input, select { font: inherit; }
button { cursor: pointer; }
button, input, select { min-height: 44px; }
:focus-visible { outline: 2px solid var(--accent-forest); outline-offset: 3px; }
[hidden] { display: none !important; }
button:disabled, select:disabled, input:disabled { opacity: 0.45; cursor: not-allowed; }
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
}

.site-header, .site-footer { background: var(--bg-surface); }
.site-header { border-bottom: 1px solid var(--border-hairline); }
.header-inner, .footer-inner, .page-container { max-width: 1360px; margin: 0 auto; }
.header-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
  padding: 20px 24px;
}
.brand-group { display: grid; gap: 2px; }
.wordmark { font: 700 1.65rem/1.2 var(--font-serif); letter-spacing: -0.03em; }
.brand-sub, .footer-copy { font-size: 0.82rem; color: var(--text-muted); }
.header-meta { display: flex; flex-wrap: wrap; gap: 8px; }
.meta-badge, .mode-badge, .category-badge {
  display: inline-block;
  padding: 4px 8px;
  font-size: 0.73rem;
  font-weight: 600;
  background: var(--accent-tint);
  color: var(--accent-forest);
  border-radius: 4px;
}
.page-container { padding: 0 24px 64px; }
.hero-section { padding: 52px 0 36px; }
.hero-title {
  font: 700 clamp(2rem, 4vw, 3.4rem)/1.1 var(--font-serif);
  letter-spacing: -0.035em;
  margin-bottom: 16px;
}
.hero-lead { max-width: 820px; color: var(--text-secondary); font-size: 1.05rem; }
.studio-grid { display: grid; grid-template-columns: minmax(0, 1.2fr) minmax(0, 1fr); gap: 28px; align-items: start; }
.studio-column, .curriculum-column { min-width: 0; }
.studio-card, .curriculum-card {
  padding: 24px;
  border: 1px solid var(--border-hairline);
  border-radius: 8px;
  background: var(--bg-surface);
  min-width: 0;
}
.studio-header, .curriculum-header {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  padding-bottom: 16px;
  margin-bottom: 16px;
  border-bottom: 1px solid var(--border-hairline);
}
.studio-status-group { display: flex; flex-wrap: wrap; align-items: center; gap: 8px; }
.studio-label, .panel-hint, .notation-intro { color: var(--text-muted); font-size: 0.82rem; }
.size-tag, .counter-badge, .speed-metric { font-family: var(--font-mono); font-size: 0.85rem; }
.mode-badge[data-mode="practice"] { background: #fbf3db; color: #795a16; }
.camera-controls { display: flex; flex-wrap: wrap; gap: 4px; }
.btn-camera {
  padding: 6px 8px;
  background: transparent;
  border: 1px solid var(--border-hairline);
  border-radius: 4px;
  font-size: 0.75rem;
  color: var(--text-secondary);
}
.btn-camera:hover { background: var(--bg-surface-alt); }
.viewport-box { border: 1px solid var(--border-hairline); }
.status-banner { margin-top: 12px; font-size: 0.85rem; color: var(--text-secondary); min-height: 2.8em; }
.playback-panel, .practice-panel, .dimension-panel {
  margin-top: 24px;
  padding-top: 20px;
  border-top: 1px solid var(--border-hairline);
}
.strip-header, .speed-labels { display: flex; justify-content: space-between; align-items: baseline; flex-wrap: wrap; gap: 8px; }
.panel-eyebrow, .section-heading {
  font-size: 0.74rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--text-muted);
}
.formula-box { display: flex; flex-wrap: wrap; align-items: center; gap: 6px; margin: 12px 0 16px; min-height: 44px; }
.move-token {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  padding: 4px 8px;
  min-width: 32px;
  text-align: center;
  background: var(--bg-surface-alt);
  border: 1px solid var(--border-hairline);
  border-radius: 4px;
}
.move-token.is-complete { color: var(--text-muted); }
.move-token.is-current { background: var(--accent-forest); color: #ffffff; border-color: var(--accent-forest); }
.playback-buttons { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 8px; }
.btn {
  padding: 8px 10px;
  border: 1px solid var(--border-medium);
  border-radius: 4px;
  font-size: 0.85rem;
  font-weight: 600;
  background: var(--bg-surface-alt);
  color: var(--text-primary);
}
.btn-primary { background: var(--accent-forest); border-color: var(--accent-forest); color: #ffffff; }
.btn-primary:hover:not(:disabled) { background: var(--accent-forest-hover); }
.btn-outline { background: transparent; }
.btn-secondary:hover:not(:disabled), .btn-outline:hover:not(:disabled) { background: var(--accent-tint); }
.speed-control-group { margin-top: 16px; }
.control-label { color: var(--text-secondary); font-size: 0.85rem; }
.range-slider { width: 100%; accent-color: var(--accent-forest); cursor: pointer; }
.panel-heading-row { margin-bottom: 14px; }
.panel-title, .notation-title { font: 700 1.2rem/1.3 var(--font-serif); }
.practice-options { display: flex; align-items: center; flex-wrap: wrap; gap: 12px; margin-bottom: 16px; }
.option-field { display: flex; flex-wrap: wrap; align-items: center; gap: 8px; min-width: 0; }
.select-input, .number-input {
  max-width: 100%;
  min-width: 0;
  padding: 8px 10px;
  border: 1px solid var(--border-medium);
  border-radius: 4px;
  background: var(--bg-surface);
  color: var(--text-primary);
  font-size: 0.85rem;
}
.checkbox-label { display: flex; align-items: center; gap: 8px; font-size: 0.85rem; cursor: pointer; }
.checkbox-input { min-height: 18px; width: 18px; height: 18px; flex-shrink: 0; accent-color: var(--accent-forest); }
.face-keypad { display: grid; grid-template-columns: repeat(6, minmax(0, 1fr)); gap: 8px; }
.btn-face {
  background: var(--bg-surface-alt);
  color: var(--text-primary);
  border: 1px solid var(--border-hairline);
  border-radius: 4px;
  padding: 10px 4px;
  font: 700 1.05rem var(--font-mono);
}
.btn-face:hover:not(:disabled) { background: var(--accent-tint); border-color: var(--accent-forest); }
.preset-group { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 16px; }
.btn-preset {
  padding: 8px 10px;
  border: 1px solid var(--border-hairline);
  border-radius: 4px;
  background: var(--bg-surface);
  color: var(--text-primary);
  font-size: 0.8rem;
}
.btn-preset[aria-pressed="true"] { background: var(--accent-tint); border-color: var(--accent-forest); color: var(--accent-forest); }
.form-row { display: grid; gap: 8px; }
.input-action-cluster { display: flex; flex-wrap: wrap; gap: 8px; }
.number-input { width: 88px; font-family: var(--font-mono); }
.alert-box { padding: 12px 16px; margin: 16px 0; border-radius: 4px; font-size: 0.9rem; }
.alert-danger { background: var(--danger-bg); color: var(--danger-text); border: 1px solid var(--danger-border); }
.form-error { margin-bottom: 0; }
.guidance-box { margin-top: 16px; font-size: 0.85rem; color: var(--text-secondary); }
.guidance-title { font: 700 0.95rem var(--font-serif); margin-bottom: 8px; }
.guidance-box p + p { margin-top: 8px; }
.quick-nav-field { min-width: 0; max-width: 100%; }
.select-lesson { width: 100%; max-width: 290px; }
.lesson-navigation { margin-bottom: 28px; }
.lesson-nav-list { list-style: none; padding: 0; }
.lesson-nav-button {
  display: flex;
  align-items: baseline;
  gap: 12px;
  width: 100%;
  padding: 12px 8px;
  text-align: left;
  border: 0;
  border-bottom: 1px solid var(--border-hairline);
  border-radius: 0;
  background: transparent;
  color: var(--text-primary);
  font-size: 0.88rem;
}
.lesson-nav-button:hover { background: var(--bg-surface-alt); }
.lesson-nav-button[aria-current="step"] { color: var(--accent-forest); background: var(--accent-tint); font-weight: 600; }
.lesson-number { font-family: var(--font-mono); font-size: 0.8rem; flex-shrink: 0; color: var(--accent-forest); }
.lesson-nav-title { min-width: 0; }
.lesson-detail { display: grid; gap: 24px; }
.detail-header { padding-bottom: 20px; border-bottom: 1px solid var(--border-hairline); }
.lesson-title { margin: 12px 0 10px; font: 700 1.6rem/1.25 var(--font-serif); letter-spacing: -0.02em; }
.lesson-summary { font-size: 0.95rem; color: var(--text-secondary); }
.detail-section { display: grid; gap: 8px; }
.section-body, .detail-list, .detail-steps-list { font-size: 0.95rem; line-height: 1.65; }
.detail-list, .detail-steps-list { padding-left: 22px; }
.detail-list li + li, .detail-steps-list li + li { margin-top: 8px; }
.goal-section { border-left: 3px solid var(--accent-forest); padding-left: 16px; }
.sample-note-section { padding-top: 20px; border-top: 1px solid var(--border-hairline); }
.sample-note-body { font-size: 0.85rem; color: var(--text-secondary); }
.notation-section { margin-top: 32px; padding-top: 24px; border-top: 1px solid var(--border-hairline); }
.notation-intro { margin: 8px 0 16px; }
.notation-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(150px, 100%), 1fr)); gap: 16px; }
.notation-item { display: grid; align-content: start; gap: 4px; padding-top: 12px; border-top: 1px solid var(--border-hairline); }
.notation-symbol { font: 700 1rem var(--font-mono); color: var(--accent-forest); }
.notation-name { font-size: 0.85rem; }
.notation-desc { font-size: 0.78rem; color: var(--text-secondary); }
.site-footer { padding: 28px 24px; border-top: 1px solid var(--border-hairline); }
.footer-title { font: 700 1rem var(--font-serif); margin-bottom: 8px; }
.footer-text { color: var(--text-secondary); font-size: 0.85rem; max-width: 850px; }
.footer-copy { margin-top: 16px; }
.hero-lead, .lesson-detail, .lesson-nav-title, .guidance-box, .notation-desc { overflow-wrap: anywhere; }

@media (max-width: 960px) {
  .studio-grid { grid-template-columns: minmax(0, 1fr); gap: 24px; }
  .header-inner, .site-footer { padding-left: 16px; padding-right: 16px; }
  .page-container { padding: 0 16px 40px; }
  .hero-section { padding: 36px 0 28px; }
}
@media (max-width: 480px) {
  .studio-card, .curriculum-card { padding: 16px; }
  .header-meta { display: none; }
  .playback-buttons { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .face-keypad { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .lesson-title { font-size: 1.4rem; }
}