/* ============================================================
 * BioQuest Homepage — Premium Botanical Laboratory Theme
 * Design: Deep forest greens, amber/gold accents, cream bg
 * ============================================================ */

/* ----- HERO ----- */
.hero {
  position: relative;
  min-height: 100svh;
  display: flex;
  align-items: center;
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
}

.hero-bg canvas {
  display: block;
  width: 100%;
  height: 100%;
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(
    160deg,
    rgba(18, 32, 22, 0.96) 0%,
    rgba(26, 47, 29, 0.88) 35%,
    rgba(45, 74, 43, 0.65) 70%,
    rgba(90, 125, 92, 0.45) 100%
  );
  z-index: 1;
  pointer-events: none;
}

.hero-gradient-left {
  position: absolute;
  top: 0;
  left: 0;
  bottom: 0;
  width: 55%;
  background: linear-gradient(
    90deg,
    rgba(12, 24, 16, 0.5) 0%,
    rgba(18, 32, 22, 0.3) 40%,
    transparent 100%
  );
  z-index: 1;
  pointer-events: none;
}

.hero-content {
  position: relative;
  z-index: 2;
  width: 100%;
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: 0 var(--content-padding);
  padding-top: calc(var(--header-height) + 40px);
  padding-bottom: 80px;
}

.hero-label {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 500;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--marigold);
  background: rgba(196, 149, 106, 0.12);
  padding: 7px 16px;
  border-radius: var(--radius-pill, 20px);
  border: 1px solid rgba(196, 149, 106, 0.18);
  margin-bottom: 32px;
  animation: heroFadeIn 0.8s ease forwards;
}

.hero-title {
  font-family: var(--font-serif);
  font-size: clamp(2.8rem, 6vw, 4.4rem);
  color: #fff;
  line-height: 1.1;
  letter-spacing: -0.02em;
  margin-bottom: 24px;
  font-weight: 700;
  animation: heroFadeIn 0.8s 0.1s ease both;
}

.hero-title-accent {
  background: linear-gradient(120deg, #e8a830, #d4a574, #e8a830);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: 1.12rem;
  color: rgba(255, 255, 255, 0.65);
  line-height: 1.75;
  margin-bottom: 40px;
  max-width: 560px;
  animation: heroFadeIn 0.8s 0.2s ease both;
}

.hero-actions {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  animation: heroFadeIn 0.8s 0.3s ease both;
}

.btn-primary-hero {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-sans);
  font-size: 1rem;
  font-weight: 600;
  padding: 15px 32px;
  border-radius: var(--radius-lg, 12px);
  border: none;
  cursor: pointer;
  background: linear-gradient(135deg, var(--color-warm, #c4956a), var(--color-warm-light, #d4a574));
  color: var(--color-primary-900, #1a2f1d);
  position: relative;
  overflow: hidden;
  transition: transform 0.25s ease, box-shadow 0.25s ease, background 0.25s ease;
}

.btn-primary-hero::after {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 60%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.25), transparent);
  transition: left 0.5s ease;
}

.btn-primary-hero:hover::after {
  left: 120%;
}

.btn-primary-hero:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-button, 0 8px 28px rgba(196, 149, 106, 0.35));
  background: linear-gradient(135deg, var(--color-warm-light, #d4a574), var(--color-warm-200, #e0b98a));
}

.btn-primary-hero:active {
  transform: scale(0.97);
}

.btn-primary-hero--lg {
  font-size: 1.1rem;
  padding: 18px 40px;
  border-radius: var(--radius-xl, 14px);
}

.btn-outline-hero {
  display: inline-flex;
  align-items: center;
  font-family: var(--font-sans);
  font-size: 1rem;
  font-weight: 500;
  padding: 15px 32px;
  border-radius: var(--radius-lg, 12px);
  border: 1.5px solid rgba(255, 255, 255, 0.3);
  cursor: pointer;
  background: transparent;
  color: rgba(255, 255, 255, 0.9);
  transition: all 0.25s ease;
}

.btn-outline-hero:hover {
  border-color: rgba(255, 255, 255, 0.6);
  background: rgba(255, 255, 255, 0.08);
  transform: translateY(-2px);
}

.btn-outline-hero:active {
  transform: scale(0.97);
}

.hero-scroll-hint {
  position: absolute;
  bottom: 40px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 2;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  color: rgba(255, 255, 255, 0.35);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  animation: scrollPulse 2.5s ease-in-out infinite;
  animation: heroFadeIn 0.8s 0.6s ease both, scrollPulse 2.5s 1s ease-in-out infinite;
}

.scroll-line {
  width: 1px;
  height: 32px;
  background: rgba(255, 255, 255, 0.25);
  position: relative;
  overflow: hidden;
}

.scroll-line::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 40%;
  background: rgba(255, 255, 255, 0.5);
  animation: scrollDot 2.5s ease-in-out infinite;
}

@keyframes heroFadeIn {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes scrollPulse {
  0%, 100% { opacity: 0.35; }
  50% { opacity: 0.7; }
}

@keyframes scrollDot {
  0% { transform: translateY(-100%); }
  50% { transform: translateY(160%); }
  100% { transform: translateY(-100%); }
}

/* ----- STATS STRIP ----- */
.stats-strip {
  background: var(--color-cream);
  padding: 48px 0;
  border-bottom: 1px solid var(--border-light);
}

.stats-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0;
}

.stat-item {
  text-align: center;
  padding: 0 48px;
  transition: transform var(--transition-base), color var(--transition-base);
}

.stat-item:hover {
  transform: translateY(-3px);
}

.stat-item:hover .stat-value {
  background: linear-gradient(135deg, var(--color-mid), var(--color-amber));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.stat-value {
  font-family: var(--font-serif);
  font-size: clamp(2rem, 3.5vw, 2.8rem);
  font-weight: 700;
  color: var(--color-mid);
  line-height: 1;
  margin-bottom: 6px;
}

.stat-unit {
  font-size: 0.5em;
  font-weight: 400;
  color: var(--color-sage);
  font-family: var(--font-sans);
}

.stat-label {
  font-size: 0.85rem;
  color: var(--text-muted);
  letter-spacing: 0.04em;
}

.stat-divider {
  width: 1px;
  height: 48px;
  background: linear-gradient(to bottom, transparent, var(--border-light), transparent);
}

/* ----- MODULES ----- */
.modules-section {
  padding: 100px 0;
  background: var(--surface-secondary);
  background: linear-gradient(180deg, var(--color-cream) 0%, var(--surface-secondary) 50%, var(--color-cream) 100%);
}

.section-header {
  text-align: center;
  margin-bottom: 64px;
}

.modules-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0;
}

.module-block {
  padding: 52px 48px;
  cursor: pointer;
  transition: background 0.35s ease, transform 0.35s cubic-bezier(0.22, 1, 0.36, 1), box-shadow 0.35s ease, border-left-color 0.35s ease, border-left-width 0.35s ease;
  position: relative;
  display: flex;
  gap: 28px;
  align-items: flex-start;
  border-left: 4px solid transparent;
}

.module-block:hover {
  background: rgba(26, 58, 42, 0.03);
  transform: translateY(-3px);
  box-shadow: 0 8px 32px rgba(26, 58, 42, 0.06);
  border-left-color: var(--color-amber);
}

.module-block::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 48px;
  right: 48px;
  height: 1px;
  background: var(--border-light);
}

.module-biochem { border-top: none; border-left: none; }
.module-botany { border-top: none; border-right: none; }
.module-zoology { border-bottom: none; border-left: none; }
.module-genetics { border-bottom: none; border-right: none; }

.module-block:nth-child(odd) {
  border-right: 1px solid var(--border-light);
}

.module-icon-area {
  flex-shrink: 0;
  width: 72px;
  height: 72px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 18px;
  background: rgba(26, 58, 42, 0.04);
  transition: background 0.35s ease, transform 0.35s ease;
}

.module-block:hover .module-icon-area {
  background: rgba(26, 58, 42, 0.08);
  transform: scale(1.05);
}

.module-icon-svg {
  color: var(--color-sage);
  transition: color 0.35s ease;
}

.module-biochem:hover .module-icon-svg { color: var(--color-mid); }
.module-botany:hover .module-icon-svg { color: #5a7d3c; }
.module-zoology:hover .module-icon-svg { color: #6a5a3c; }
.module-genetics:hover .module-icon-svg { color: #5a4a7c; }

.module-info {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.module-name {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-deep);
}

.module-subjects {
  font-family: var(--font-serif);
  font-size: 1.1rem;
  color: var(--color-amber);
  font-weight: 600;
}

.module-desc {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.7;
  max-width: 380px;
}

/* ----- CTA ----- */
.cta-section {
  padding: 100px 0;
  background: var(--color-deep);
  background: linear-gradient(160deg, #1a2f1d, #0c1810), radial-gradient(ellipse at 30% 50%, rgba(196, 149, 106, 0.04) 0%, transparent 60%), radial-gradient(ellipse at 70% 80%, rgba(90, 125, 92, 0.03) 0%, transparent 50%);
  background-blend-mode: normal, normal, normal;
  position: relative;
  overflow: hidden;
}

.cta-section::before {
  content: '';
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 600px;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(196, 149, 106, 0.25), transparent);
}

.cta-block {
  text-align: center;
  max-width: 640px;
  margin: 0 auto;
}

.cta-title {
  font-family: var(--font-serif);
  font-size: clamp(1.8rem, 3.5vw, 2.6rem);
  color: #fff;
  font-weight: 700;
  margin-bottom: 16px;
  letter-spacing: -0.01em;
}

.cta-subtitle {
  font-size: 1.05rem;
  color: rgba(255, 255, 255, 0.6);
  margin-bottom: 40px;
  line-height: 1.7;
}

.cta-actions {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}

.btn-secondary-cta {
  display: inline-flex;
  align-items: center;
  font-family: var(--font-sans);
  font-size: 1rem;
  font-weight: 500;
  padding: 15px 32px;
  border-radius: var(--radius-lg, 12px);
  border: 1.5px solid rgba(255, 255, 255, 0.2);
  cursor: pointer;
  background: transparent;
  color: rgba(255, 255, 255, 0.8);
  transition: all 0.25s ease;
}

.btn-secondary-cta:hover {
  border-color: rgba(255, 255, 255, 0.5);
  background: rgba(255, 255, 255, 0.06);
  transform: translateY(-2px);
}

.btn-secondary-cta:active {
  transform: scale(0.97);
}

/* ============================================================
 * SCROLL-TRIGGERED ANIMATIONS
 * ============================================================ */
.section-reveal {
  opacity: 0;
  transform: translateY(40px);
  transition: opacity 0.8s cubic-bezier(0.22, 1, 0.36, 1),
              transform 0.8s cubic-bezier(0.22, 1, 0.36, 1);
}

.section-reveal--visible {
  opacity: 1;
  transform: translateY(0);
}

/* Staggered reveal for children */
.section-reveal-child {
  opacity: 0;
  transform: translateY(24px) scale(0.97);
  transition: opacity 0.6s cubic-bezier(0.22, 1, 0.36, 1),
              transform 0.6s cubic-bezier(0.22, 1, 0.36, 1);
}

.section-reveal-child--visible {
  opacity: 1;
  transform: translateY(0) scale(1);
}

/* Scroll down indicator - smooth */
.scroll-down-indicator {
  position: fixed;
  bottom: 24px;
  right: 24px;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--color-mid);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  z-index: 50;
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.3s ease, transform 0.3s ease;
  box-shadow: 0 4px 16px rgba(0,0,0,0.2);
  border: none;
}

.scroll-down-indicator--visible {
  opacity: 1;
  transform: translateY(0);
}

.scroll-down-indicator:hover {
  background: var(--color-sage);
  transform: translateY(-2px);
  box-shadow: 0 6px 24px rgba(0,0,0,0.25);
}

/* ============================================================
 * RESPONSIVE
 * ============================================================ */
@media (max-width: 1024px) {
  .hero-content {
    padding: 0 40px;
    padding-top: calc(var(--header-height) + 40px);
  }

  .modules-grid {
    grid-template-columns: 1fr;
  }

  .module-block {
    padding: 40px 32px;
  }

  .module-block:nth-child(odd) {
    border-right: none;
  }

  .module-block::after {
    left: 32px;
    right: 32px;
  }
}

@media (max-width: 768px) {
  .hero {
    min-height: 90svh;
  }

  .hero-content {
    padding: 0 24px;
    padding-top: calc(var(--header-height) + 24px);
    padding-bottom: 80px;
  }

  .hero-title {
    font-size: clamp(2rem, 7vw, 2.8rem);
  }

  .hero-subtitle {
    font-size: 1rem;
  }

  .hero-actions {
    flex-direction: column;
    gap: 12px;
  }

  .btn-primary-hero,
  .btn-outline-hero {
    width: 100%;
    justify-content: center;
  }

  .hero-scroll-hint {
    display: none;
  }

  .stats-row {
    flex-wrap: wrap;
    gap: 24px;
  }

  .stat-item {
    padding: 0 24px;
  }

  .stat-divider {
    display: none;
  }

  .modules-section {
    padding: 64px 0;
  }

  .section-header {
    margin-bottom: 40px;
  }

  .module-block {
    padding: 32px 24px;
    flex-direction: column;
    gap: 16px;
  }

  .module-icon-area {
    width: 56px;
    height: 56px;
    border-radius: 14px;
  }

  .cta-section {
    padding: 64px 0;
  }
}

@media (max-width: 480px) {
  .hero-title {
    font-size: 1.8rem;
  }
  .daily-question-card {
    padding: 20px 16px;
  }
  .hero-subtitle {
    font-size: 0.85rem;
  }
  .hero-actions {
    flex-direction: column;
    gap: 10px;
    width: 100%;
  }
  .hero-actions a {
    width: 100%;
    text-align: center;
  }
}

/* ====== 每日一题 ====== */
.daily-question-section {
  padding: 60px 0 40px;
  background: linear-gradient(135deg, rgba(90,125,92,0.04) 0%, rgba(232,168,48,0.04) 100%);
}

.daily-question-card {
  max-width: 720px;
  margin: 0 auto;
  background: var(--surface, #fff);
  border-radius: 16px;
  padding: 32px;
  box-shadow: 0 4px 24px rgba(0,0,0,0.06);
  border: 1px solid var(--border, #e8e6e1);
}

.dq-header {
  margin-bottom: 20px;
}

.dq-meta {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.dq-badge {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 12px;
  font-size: 0.75rem;
  font-weight: 600;
  background: rgba(232,168,48,0.12);
  color: #c0880a;
}

.dq-subject {
  font-size: 0.8rem;
  color: var(--text-muted, #888);
}

.dq-streak {
  font-size: 0.8rem;
  color: #e8a830;
  font-weight: 600;
  margin-left: auto;
}

.dq-question {
  font-size: 1.1rem;
  font-weight: 600;
  line-height: 1.7;
  margin-bottom: 24px;
  color: var(--text-primary, #1a2f1d);
}

.dq-options {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.dq-option {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 14px 18px;
  border: 1.5px solid var(--border, #e0e0e0);
  border-radius: 12px;
  cursor: pointer;
  transition: all 0.2s;
}

.dq-option:hover {
  border-color: var(--color-sage, #5a7d5c);
  background: rgba(90,125,92,0.04);
}

.dq-marker {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  border: 2px solid var(--border, #e0e0e0);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.8rem;
  font-weight: 700;
  flex-shrink: 0;
  transition: all 0.2s;
}

.dq-text {
  font-size: 0.95rem;
  line-height: 1.6;
  padding-top: 3px;
}

.dq-selected {
  border-color: var(--color-sage, #5a7d5c);
  background: rgba(90,125,92,0.06);
}

.dq-selected .dq-marker {
  border-color: var(--color-sage, #5a7d5c);
  background: var(--color-sage, #5a7d5c);
  color: #fff;
}

.dq-correct {
  border-color: var(--success-green, #3a8c5c);
  background: rgba(58,140,92,0.06);
}

.dq-correct .dq-marker {
  border-color: var(--success-green, #3a8c5c);
  background: var(--success-green, #3a8c5c);
  color: #fff;
}

.dq-wrong {
  border-color: var(--terracotta, #c0553a);
  background: rgba(192,85,58,0.06);
}

.dq-wrong .dq-marker {
  border-color: var(--terracotta, #c0553a);
  background: var(--terracotta, #c0553a);
  color: #fff;
}

.dq-result {
  margin-top: 20px;
  padding: 14px 18px;
  border-radius: 10px;
  font-weight: 600;
  font-size: 0.95rem;
}

.dq-result-correct {
  background: rgba(58,140,92,0.1);
  color: var(--success-green, #3a8c5c);
}

.dq-result-wrong {
  background: rgba(192,85,58,0.1);
  color: var(--terracotta, #c0553a);
}

.dq-explanation {
  margin-top: 16px;
  padding: 18px;
  background: rgba(232,168,48,0.06);
  border-radius: 10px;
  border-left: 3px solid #e8a830;
}

.dq-explanation-title {
  font-weight: 600;
  font-size: 0.85rem;
  color: #c0880a;
  margin-bottom: 8px;
}

.dq-explanation-text {
  font-size: 0.9rem;
  line-height: 1.7;
  color: var(--text-secondary, #555);
}

/* ============================================================
 * 生物学史滑动式时间轴 — 签名区域
 * 设计：深色森林底 + 琥珀金点缀 + 噪点纹理 + 不对称布局
 * ============================================================ */

.biology-history-section {
  position: relative;
  padding: 96px 0 120px;
  background:
    radial-gradient(ellipse at 20% 20%, rgba(196, 149, 106, 0.12) 0%, transparent 45%),
    radial-gradient(ellipse at 85% 80%, rgba(90, 125, 92, 0.1) 0%, transparent 40%),
    linear-gradient(160deg, #1a2f1d 0%, #14261a 50%, #1a2f1d 100%);
  overflow: hidden;
  isolation: isolate;
}

/* 噪点纹理层 */
.biology-history-section::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noise)' opacity='0.06'/%3E%3C/svg%3E");
  opacity: 0.7;
  pointer-events: none;
  mix-blend-mode: overlay;
  z-index: 0;
}

/* 顶部斜切装饰线 */
.biology-history-section::after {
  content: '';
  position: absolute;
  top: -60px;
  left: -5%;
  width: 110%;
  height: 120px;
  background: linear-gradient(90deg, transparent, rgba(196, 149, 106, 0.08), transparent);
  transform: rotate(-2deg);
  pointer-events: none;
  z-index: 1;
}

.biology-history-header {
  position: relative;
  z-index: 2;
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: 0 var(--content-padding);
  margin-bottom: 56px;
  padding-left: clamp(24px, 8vw, 96px);
}

.biology-history-label {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-amber-light);
  margin-bottom: 14px;
  opacity: 0.85;
}

.biology-history-title-main {
  font-family: var(--font-serif);
  font-size: clamp(2rem, 5vw, 3.2rem);
  font-weight: 700;
  color: #f5f0e8;
  line-height: 1.15;
  margin-bottom: 16px;
  letter-spacing: -0.02em;
}

.biology-history-subtitle {
  font-family: var(--font-sans);
  font-size: 1.05rem;
  font-weight: 400;
  color: rgba(245, 240, 232, 0.65);
  line-height: 1.75;
  max-width: 560px;
}

.biology-history-vertical {
  position: relative;
  z-index: 2;
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: 0 var(--content-padding);
}

.bio-history-category {
  margin-bottom: 72px;
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.7s cubic-bezier(0.22, 1, 0.36, 1),
              transform 0.7s cubic-bezier(0.22, 1, 0.36, 1);
}

.bio-history-category.is-visible {
  opacity: 1;
  transform: translateY(0);
}

.bio-history-category-header {
  margin-bottom: 36px;
  padding-left: 24px;
  border-left: 3px solid var(--color-amber-light);
}

.bio-history-category-title {
  font-family: var(--font-serif);
  font-size: clamp(1.4rem, 3vw, 1.9rem);
  font-weight: 700;
  color: #f5f0e8;
  margin-bottom: 8px;
  letter-spacing: -0.01em;
}

.bio-history-category-subtitle {
  font-family: var(--font-sans);
  font-size: 0.95rem;
  color: rgba(245, 240, 232, 0.62);
  line-height: 1.65;
  max-width: 560px;
}

.bio-history-timeline {
  position: relative;
  padding-left: 92px;
}

.bio-history-timeline::before {
  content: '';
  position: absolute;
  top: 12px;
  bottom: 12px;
  left: 38px;
  width: 2px;
  background: linear-gradient(180deg, rgba(196, 149, 106, 0.55), rgba(196, 149, 106, 0.25) 80%, transparent);
  border-radius: 999px;
}

.bio-history-event {
  position: relative;
  margin-bottom: 28px;
  opacity: 0;
  transform: translateX(-20px);
  transition: opacity 0.55s cubic-bezier(0.22, 1, 0.36, 1),
              transform 0.55s cubic-bezier(0.22, 1, 0.36, 1);
  cursor: pointer;
}

.bio-history-event.is-visible {
  opacity: 1;
  transform: translateX(0);
}

.bio-history-event:focus-visible {
  outline: none;
}

.bio-history-event:focus-visible .bio-history-card {
  box-shadow: 0 0 0 3px rgba(196, 149, 106, 0.45), 0 12px 40px rgba(0, 0, 0, 0.22);
}

.bio-history-year-badge {
  position: absolute;
  left: -92px;
  top: 6px;
  width: 76px;
  text-align: right;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--color-amber-light);
  letter-spacing: 0.02em;
  z-index: 2;
}

.bio-history-line {
  position: absolute;
  left: -58px;
  top: 14px;
  width: 20px;
  height: 2px;
  background: rgba(196, 149, 106, 0.45);
  border-radius: 999px;
}

.bio-history-line::after {
  content: '';
  position: absolute;
  right: -6px;
  top: 50%;
  transform: translateY(-50%);
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--color-amber-light);
  box-shadow: 0 0 0 4px rgba(196, 149, 106, 0.2);
}

.bio-history-card {
  position: relative;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 18px;
  padding: 22px 24px;
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  transition: transform 0.3s cubic-bezier(0.22, 1, 0.36, 1),
              background 0.3s ease,
              border-color 0.3s ease,
              box-shadow 0.3s ease;
  box-shadow: 0 8px 28px rgba(0, 0, 0, 0.16);
}

.bio-history-event:hover .bio-history-card,
.bio-history-event--expanded .bio-history-card {
  background: rgba(255, 255, 255, 0.1);
  border-color: rgba(196, 149, 106, 0.3);
  transform: translateY(-4px);
  box-shadow: 0 14px 40px rgba(0, 0, 0, 0.24);
}

.bio-history-card-year {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--color-amber-light);
  margin-bottom: 6px;
  opacity: 0.8;
}

.bio-history-card-title {
  font-family: var(--font-serif);
  font-size: 1.15rem;
  font-weight: 700;
  color: #f5f0e8;
  line-height: 1.35;
  margin-bottom: 8px;
}

.bio-history-card-detail {
  font-family: var(--font-sans);
  font-size: 0.92rem;
  font-weight: 400;
  color: rgba(245, 240, 232, 0.55);
  line-height: 1.7;
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  transform: translateY(-6px);
  transition: max-height 0.45s cubic-bezier(0.22, 1, 0.36, 1),
              opacity 0.35s ease,
              transform 0.35s ease,
              margin-top 0.35s ease;
}

.bio-history-event--expanded .bio-history-card-detail {
  max-height: 260px;
  opacity: 1;
  transform: translateY(0);
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
}

/* 浅色模式适配 */
[data-theme="light"] .biology-history-section {
  background:
    radial-gradient(ellipse at 20% 20%, rgba(196, 149, 106, 0.12) 0%, transparent 45%),
    radial-gradient(ellipse at 85% 80%, rgba(90, 125, 92, 0.08) 0%, transparent 40%),
    linear-gradient(160deg, #1b3a2d 0%, #162f22 50%, #1b3a2d 100%);
}

[data-theme="light"] .biology-history-title-main,
[data-theme="light"] .bio-history-category-title,
[data-theme="light"] .bio-history-card-title {
  color: #f8f4ec;
}

[data-theme="light"] .biology-history-subtitle,
[data-theme="light"] .bio-history-category-subtitle {
  color: rgba(248, 244, 236, 0.68);
}

[data-theme="light"] .bio-history-card-detail {
  color: rgba(248, 244, 236, 0.55);
}

/* 响应式 */
@media (max-width: 768px) {
  .biology-history-section {
    padding: 64px 0 80px;
  }

  .biology-history-header {
    padding-left: var(--content-padding);
    margin-bottom: 40px;
  }

  .biology-history-title-main {
    font-size: clamp(1.7rem, 6vw, 2.2rem);
  }

  .biology-history-subtitle {
    font-size: 0.95rem;
  }

  .bio-history-timeline {
    padding-left: 64px;
  }

  .bio-history-year-badge {
    left: -64px;
    width: 52px;
    font-size: 0.78rem;
  }

  .bio-history-line {
    left: -40px;
    width: 14px;
  }

  .bio-history-card {
    padding: 18px 20px;
  }

  .bio-history-card-title {
    font-size: 1.05rem;
  }

  .bio-history-card-detail {
    font-size: 0.88rem;
  }
}