*, *::before, *::after { box-sizing: border-box; }
html { font-size: var(--fs-base); scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font-family);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
}
body.has-contact-footer {
  padding-bottom: calc(var(--contact-footer-h) + var(--bottom-nav-h) + var(--safe-area-bottom));
}
.container { max-width: 960px; margin: 0 auto; padding: 0 16px; }
.section-title { font-size: var(--fs-h2); color: var(--color-primary); margin: 0 0 8px; }
.section-desc { color: var(--color-text-secondary); margin: 0 0 24px; }
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  padding: 10px 18px; border-radius: 10px; border: none;
  font-size: 15px; cursor: pointer; text-decoration: none;
  font-family: inherit;
}
.btn-primary { background: var(--color-primary); color: #fff; font-weight: 600; }
.btn-secondary { background: var(--color-bg-card); color: var(--color-text); border: 1px solid var(--color-border); }
.skip-link { position: absolute; left: -9999px; top: 0; z-index: 9999; padding: 8px 16px; background: #000; color: #fff; }
.skip-link:focus { left: 0; }
.navbar {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  background: rgba(255,255,255,0.92); backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--color-border);
}
[data-theme="tech"] .navbar { background: rgba(15,23,42,0.92); }
.navbar-inner { display: flex; align-items: center; gap: 10px; padding: 10px 16px; }
.navbar-title { font-weight: 600; flex: 1; }
.navbar-actions { display: flex; gap: 6px; }
.navbar-actions .btn { padding: 6px 10px; font-size: 12px; }

/* 标准底栏 R28 */
.contact-footer {
  position: fixed; left: 0; right: 0; bottom: 0; z-index: 850;
  background: #1a1a1a;
  padding: .55rem .75rem calc(.55rem + var(--safe-area-bottom));
  border-top: 1px solid rgba(255,255,255,0.08);
}
.contact-footer__btns {
  display: grid; grid-template-columns: repeat(3, minmax(0, 88px));
  justify-content: center; gap: .4rem; max-width: 320px; margin: 0 auto;
}
.contact-footer__cta {
  display: block; background: #c41e1e !important; color: #fff !important;
  text-align: center; padding: .48rem .2rem; border-radius: 6px;
  font-size: .72rem; font-weight: 700; text-decoration: none; white-space: nowrap;
}
.contact-footer__btn {
  display: block; background: transparent; border: 1px solid rgba(255,255,255,0.35);
  color: #fff; padding: .48rem .2rem; border-radius: 6px; font-size: .72rem;
  cursor: pointer; text-align: center; text-decoration: none; white-space: nowrap; font-family: inherit;
}
.contact-footer__brand { text-align: center; font-size: .62rem; color: rgba(255,255,255,0.5); margin: .4rem 0 0; }
body.has-contact-footer .zw-root .zw-fab { bottom: calc(var(--contact-footer-h) + 12px + var(--safe-area-bottom)); }

.chapter { min-height: 100vh; padding: 64px 0 48px; scroll-snap-align: start; }
main.snap-scroll { scroll-snap-type: y proximity; }
.chapter-hero {
  display: flex; align-items: center; justify-content: center; text-align: center;
  background: linear-gradient(160deg, var(--color-primary), var(--color-accent));
  color: #fff; position: relative;
}
.hero-badge {
  width: 120px; height: 120px; margin: 0 auto 16px; border-radius: 50%;
  border: 4px solid rgba(255,255,255,0.5); object-fit: cover;
  animation: badgeFocus 1.2s ease both;
}
@keyframes badgeFocus { from { filter: blur(8px); opacity: 0.5; } to { filter: none; opacity: 1; } }
.hero-motto { font-size: clamp(1.5rem, 5vw, 2.5rem); font-weight: 700; margin: 12px 0; font-family: "KaiTi", serif; }
.bottom-nav {
  position: fixed; bottom: calc(var(--contact-footer-h) + var(--safe-area-bottom));
  left: 0; right: 0; z-index: 800; height: var(--bottom-nav-h);
  background: var(--color-bg-card); border-top: 1px solid var(--color-border);
  padding: 4px 8px; box-sizing: border-box;
}
.bottom-nav ul { display: flex; justify-content: space-around; list-style: none; margin: 0; padding: 0; }
.bottom-nav a { color: var(--color-text-secondary); text-decoration: none; font-size: 11px; padding: 4px; }
.bottom-nav a.active { color: var(--color-primary); font-weight: 600; }

.culture-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 12px; }
@media (min-width: 768px) { .culture-grid { grid-template-columns: repeat(3, 1fr); } }
.culture-card {
  background: var(--color-bg-card); border: 1px solid var(--color-border);
  border-radius: 12px; padding: 16px; text-align: center;
}
.flag-wave {
  height: 80px; border-radius: 8px; animation: flagWave 3s ease-in-out infinite;
  background: linear-gradient(90deg, var(--flag-primary, #C41E2A), var(--flag-secondary, #DAA520));
}
@keyframes flagWave {
  0%, 100% { transform: skewY(0deg); }
  50% { transform: skewY(2deg) scaleX(1.02); }
}
.typewriter { font-size: 1.1rem; color: var(--color-primary); min-height: 1.5em; }
.typewriter-cursor { animation: blink 1s step-end infinite; }
@keyframes blink { 50% { opacity: 0; } }

.timeline-list { display: flex; flex-direction: column; gap: 16px; }
.timeline-item {
  background: var(--color-bg-card); border-radius: 12px; padding: 16px;
  border-left: 4px solid var(--color-primary); opacity: 0.6;
}
.timeline-item.visible { opacity: 1; animation: fadeUp .5s ease both; }
@keyframes fadeUp { from { opacity: 0; transform: translateY(16px); } to { opacity: 1; transform: none; } }

.students-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 12px; }
@media (min-width: 768px) { .students-grid { grid-template-columns: repeat(4, 1fr); } }
.student-card {
  background: var(--color-bg-card); border-radius: 12px; padding: 12px;
  border: 1px solid var(--color-border); transition: transform .2s;
}
.student-card:hover { transform: translateY(-4px); }
.student-avatar {
  width: 64px; height: 64px; border-radius: 50%; margin: 0 auto 8px;
  background: var(--color-border); object-fit: cover;
}

.cube-scene { perspective: 800px; height: 280px; display: flex; align-items: center; justify-content: center; }
.cube {
  width: 160px; height: 160px; position: relative; transform-style: preserve-3d;
  animation: cubeSpin 12s linear infinite;
}
.cube:hover { animation-play-state: paused; }
@keyframes cubeSpin { from { transform: rotateX(-15deg) rotateY(0); } to { transform: rotateX(-15deg) rotateY(360deg); } }
.cube-face {
  position: absolute; width: 160px; height: 160px;
  border: 2px solid var(--color-primary); border-radius: 8px;
  background: var(--color-bg-card); display: flex; align-items: center; justify-content: center;
  font-size: 13px; padding: 8px; text-align: center; backface-visibility: hidden;
}
.cube-face.front { transform: translateZ(80px); }
.cube-face.back { transform: rotateY(180deg) translateZ(80px); }
.cube-face.left { transform: rotateY(-90deg) translateZ(80px); }
.cube-face.right { transform: rotateY(90deg) translateZ(80px); }
.cube-face.top { transform: rotateX(90deg) translateZ(80px); }
.cube-face.bottom { transform: rotateX(-90deg) translateZ(80px); }

.message-card {
  background: var(--color-bg-card); border-radius: 16px; padding: 24px;
  border: 1px solid var(--color-border); max-width: 640px; margin: 0 auto;
}
.teacher-photo { width: 80px; height: 80px; border-radius: 50%; object-fit: cover; margin-bottom: 12px; }
.share-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 16px; }
.share-landing-card {
  background: var(--color-bg-card); border-radius: 16px; padding: 24px;
  border: 1px solid var(--color-border); text-align: center;
}
.audio-player { width: 100%; margin-top: 8px; }
.fab-top {
  position: fixed; right: 16px;
  bottom: calc(var(--contact-footer-h) + var(--bottom-nav-h) + 16px + var(--safe-area-bottom));
  width: 44px; height: 44px; border-radius: 50%; border: 1px solid var(--color-border);
  background: var(--color-bg-card); cursor: pointer; z-index: 120;
}
.a11y-toolbar {
  position: fixed; left: 8px;
  bottom: calc(var(--contact-footer-h) + var(--bottom-nav-h) + 12px + var(--safe-area-bottom));
  z-index: 120; display: flex; flex-direction: column; gap: 4px;
}
.a11y-toolbar button {
  width: 36px; height: 36px; border-radius: 8px; border: 1px solid var(--color-border);
  background: var(--color-bg-card); cursor: pointer; font-size: 12px;
}
.editor-page { padding: 16px; max-width: 720px; margin: 0 auto; }
.form-field { margin-bottom: 14px; }
.form-field label { display: block; font-size: 13px; margin-bottom: 4px; color: var(--color-text-secondary); }
.form-field input, .form-field textarea, .form-field select {
  width: 100%; padding: 10px; border-radius: 8px; border: 1px solid var(--color-border);
  background: var(--color-bg-card); color: var(--color-text); font-family: inherit;
}
.editor-hint { font-size: 13px; color: var(--color-text-secondary); margin: 0 16px 12px; line-height: 1.5; }
.editor-section-title { font-size: 17px; margin: 20px 0 10px; padding-top: 8px; border-top: 1px solid var(--color-border); }
.field-hint { display: block; font-size: 12px; color: var(--color-text-secondary); margin-top: 4px; }
.student-editor-row {
  margin-bottom: 16px; padding: 12px; border-radius: 12px;
  border: 1px solid var(--color-border); background: var(--color-bg-card);
}
.student-editor-row__head { display: flex; justify-content: space-between; align-items: center; margin-bottom: 8px; }
.btn-sm { padding: 6px 12px; font-size: 13px; }
.student-editor-star { display: flex; align-items: center; gap: 8px; font-size: 14px; margin-top: 4px; }
.editor-actions { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 20px; }
.import-toolbar { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 8px; }
.import-hint { margin-top: 0; }
.hidden-input { position: absolute; width: 0; height: 0; opacity: 0; pointer-events: none; }
.avatar-field {
  display: flex; align-items: center; gap: 12px; margin-bottom: 10px;
}
.avatar-preview {
  width: 56px; height: 56px; border-radius: 50%; object-fit: cover;
  background: var(--color-border); flex-shrink: 0;
}
.avatar-field__actions { flex: 1; }
.editor-modal {
  position: fixed; inset: 0; z-index: 200; background: rgba(0,0,0,.45);
  display: flex; align-items: center; justify-content: center; padding: 16px;
}
.editor-modal.hidden { display: none; }
.editor-modal__panel {
  background: var(--color-bg-card); border-radius: 16px; padding: 16px;
  max-width: 480px; width: 100%; box-shadow: 0 8px 32px rgba(0,0,0,.15);
}
.editor-modal__panel textarea {
  width: 100%; padding: 10px; border-radius: 8px; border: 1px solid var(--color-border);
  font-family: inherit; margin: 8px 0; resize: vertical;
}
.editor-modal__actions { display: flex; gap: 8px; margin-top: 12px; }
.import-mode { display: flex; flex-wrap: wrap; gap: 12px; font-size: 14px; margin: 8px 0; }
.animate-in { animation: fadeUp .6s ease both; }