/* =====================================================
   校园AI大赛 · B 版（明亮渐变活力风）
   主色渐变：linear-gradient(135deg, #7c3aed, #06b6d4)
   无外部资源，装饰全部由 CSS 完成
   ===================================================== */

/* ---------- 变量与基础 ---------- */
:root {
  --grad-main: linear-gradient(135deg, #7c3aed, #06b6d4);
  --grad-soft: linear-gradient(135deg, rgba(124, 58, 237, .12), rgba(6, 182, 212, .12));
  --c-primary: #7c3aed;
  --c-cyan: #06b6d4;
  --c-pink: #ec4899;
  --c-ink: #1e1b33;
  --c-ink-soft: #55516e;
  --c-muted: #8a87a3;
  --c-bg: #f7f8fd;
  --c-card: #ffffff;
  --c-border: rgba(124, 58, 237, .10);
  --shadow-card: 0 10px 30px rgba(94, 62, 181, .08);
  --shadow-card-hover: 0 18px 44px rgba(94, 62, 181, .16);
  --radius-lg: 24px;
  --radius-md: 20px;
  --nav-h: 64px;
}

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

html { scroll-behavior: smooth; scroll-padding-top: calc(var(--nav-h) + 12px); }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  background: var(--c-bg);
  color: var(--c-ink);
  line-height: 1.7;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
ul, ol { list-style: none; }
strong { color: var(--c-ink); }

.container {
  width: 100%;
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 20px;
}
.container-narrow { max-width: 760px; }

/* ---------- 背景渐变 blob ---------- */
.bg-blobs {
  position: fixed;
  inset: 0;
  z-index: -1;
  overflow: hidden;
  pointer-events: none;
}
.blob {
  position: absolute;
  border-radius: 50%;
  filter: blur(110px);
  opacity: .22;
}
.blob-1 {
  width: 520px; height: 520px;
  top: -160px; left: -120px;
  background: radial-gradient(circle at 30% 30%, #7c3aed, transparent 70%);
}
.blob-2 {
  width: 620px; height: 620px;
  top: 30%; right: -220px;
  background: radial-gradient(circle at 60% 40%, #06b6d4, transparent 70%);
  opacity: .18;
}
.blob-3 {
  width: 480px; height: 480px;
  bottom: -140px; left: 12%;
  background: radial-gradient(circle at 50% 50%, #ec4899, transparent 70%);
  opacity: .14;
}

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 26px;
  border-radius: 999px;
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: .02em;
  border: 2px solid transparent;
  cursor: pointer;
  transition: transform .25s ease, box-shadow .25s ease, background-color .25s ease;
}
.btn-lg { padding: 15px 34px; font-size: 1.08rem; }
.btn:active { transform: scale(.97); }

.btn-gradient {
  background: var(--grad-main);
  color: #fff;
  box-shadow: 0 8px 22px rgba(124, 58, 237, .32);
}
.btn-gradient:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 28px rgba(124, 58, 237, .42);
}

.btn-outline {
  background: #fff;
  color: var(--c-primary);
  border-color: rgba(124, 58, 237, .35);
}
.btn-outline:hover {
  transform: translateY(-2px);
  border-color: var(--c-primary);
  box-shadow: 0 10px 24px rgba(124, 58, 237, .14);
}

.btn-white {
  background: #fff;
  color: var(--c-primary);
  box-shadow: 0 8px 24px rgba(20, 10, 60, .25);
}
.btn-white:hover { transform: translateY(-2px); box-shadow: 0 12px 30px rgba(20, 10, 60, .32); }

/* ---------- 渐变文字 ---------- */
.grad-text {
  background: var(--grad-main);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

/* =====================================================
   1. 毛玻璃 sticky 导航
   ===================================================== */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, .72);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid rgba(124, 58, 237, .08);
}

.nav-inner {
  height: var(--nav-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 900;
  font-size: 1.15rem;
  letter-spacing: -0.02em;
  white-space: nowrap;
}
.logo-mark {
  display: grid;
  place-items: center;
  width: 36px; height: 36px;
  border-radius: 12px;
  background: var(--grad-main);
  color: #fff;
  font-size: .85rem;
  font-weight: 900;
  letter-spacing: 0;
  box-shadow: 0 6px 16px rgba(124, 58, 237, .35);
}

.logo-badge {
  width: 36px; height: 36px;
  border-radius: 50%;
  object-fit: cover;
  border: 2px solid rgba(255, 255, 255, .4);
  box-shadow: 0 4px 12px rgba(0, 0, 0, .25);
  flex-shrink: 0;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 26px;
  font-weight: 600;
}
.nav-links > a:not(.btn) {
  position: relative;
  color: var(--c-ink-soft);
  padding: 4px 0;
  transition: color .2s ease;
}
.nav-links > a:not(.btn)::after {
  content: "";
  position: absolute;
  left: 0; bottom: -2px;
  width: 100%; height: 3px;
  border-radius: 3px;
  background: var(--grad-main);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform .25s ease;
}
.nav-links > a:not(.btn):hover { color: var(--c-primary); }
.nav-links > a:not(.btn):hover::after { transform: scaleX(1); }
.btn-nav { padding: 9px 20px; font-size: .92rem; }

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 42px; height: 42px;
  padding: 10px;
  border: 1px solid var(--c-border);
  border-radius: 12px;
  background: #fff;
  cursor: pointer;
}
.nav-toggle span {
  display: block;
  height: 2px;
  width: 100%;
  border-radius: 2px;
  background: var(--c-ink);
  transition: transform .25s ease, opacity .25s ease;
}
.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* =====================================================
   2. Hero
   ===================================================== */
.hero {
  padding: calc(64px - var(--nav-h) + 96px) 0 96px; /* 96px 顶部留白 */
  padding-top: 96px;
  text-align: center;
}

.hero-tag {
  display: inline-block;
  padding: 8px 18px;
  border-radius: 999px;
  background: var(--grad-soft);
  border: 1px solid rgba(124, 58, 237, .22);
  color: var(--c-primary);
  font-weight: 700;
  font-size: .95rem;
  letter-spacing: .04em;
}

.hero-title {
  margin: 26px auto 18px;
  font-size: clamp(2.4rem, 7vw, 4.2rem);
  font-weight: 900;
  line-height: 1.18;
  letter-spacing: -0.03em;
}

.hero-sub {
  max-width: 560px;
  margin: 0 auto;
  font-size: 1.12rem;
  color: var(--c-ink-soft);
}

.hero-actions {
  margin-top: 34px;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 16px;
}

/* 倒计时卡片 */
.countdown-card {
  max-width: 560px;
  margin: 52px auto 0;
  padding: 28px 24px 22px;
  background: var(--c-card);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
}
.countdown-label { font-weight: 800; letter-spacing: .06em; color: var(--c-ink-soft); }
.countdown {
  margin-top: 16px;
  display: flex;
  align-items: flex-end;
  justify-content: center;
  gap: 10px;
}
.cd-unit { display: flex; flex-direction: column; align-items: center; gap: 2px; }
.cd-num {
  min-width: 64px;
  padding: 10px 8px;
  font-size: 2.1rem;
  font-weight: 900;
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.02em;
  color: var(--c-primary);
  background: var(--c-bg);
  border: 1px solid var(--c-border);
  border-radius: 14px;
  transition: transform .12s ease;
}
.cd-num.tick { transform: scale(1.06); }
.cd-name { font-size: .82rem; color: var(--c-muted); }
.cd-sep {
  font-size: 1.6rem;
  font-weight: 900;
  color: rgba(124, 58, 237, .4);
  padding-bottom: 26px;
}
.countdown-deadline { margin-top: 14px; font-size: .9rem; color: var(--c-muted); }

/* =====================================================
   分区标题（徽章 + 大标题 + 副标）
   ===================================================== */
.section { padding: 92px 0; }

.section-head { text-align: center; margin-bottom: 52px; }

.section-badge {
  display: inline-block;
  padding: 6px 16px;
  border-radius: 999px;
  background: var(--grad-main);
  color: #fff;
  font-size: .78rem;
  font-weight: 800;
  letter-spacing: .22em;
}
.section-title {
  margin-top: 16px;
  font-size: clamp(1.7rem, 4.5vw, 2.4rem);
  font-weight: 900;
  letter-spacing: -0.02em;
}
.section-sub {
  margin-top: 10px;
  color: var(--c-ink-soft);
  font-size: 1.05rem;
}

/* ---------- 通用卡片 ---------- */
.card {
  background: var(--c-card);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
  padding: 34px 28px;
  transition: transform .3s ease, box-shadow .3s ease;
}
.card:hover { transform: translateY(-6px); box-shadow: var(--shadow-card-hover); }

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

/* =====================================================
   3. 大赛初衷
   ===================================================== */
.purpose-card { text-align: center; }
.card-emoji {
  width: 68px; height: 68px;
  margin: 0 auto 18px;
  display: grid;
  place-items: center;
  font-size: 2rem;
  border-radius: 20px;
  background: var(--grad-soft);
  border: 1px solid rgba(124, 58, 237, .14);
}
.purpose-card h3 { font-size: 1.25rem; font-weight: 800; letter-spacing: -0.01em; }
.purpose-card p { margin-top: 10px; color: var(--c-ink-soft); font-size: .97rem; }

/* =====================================================
   4. 赛道
   ===================================================== */
.track-card { position: relative; overflow: hidden; }
.track-card::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 6px;
}
.track-creative::before { background: linear-gradient(90deg, #7c3aed, #a78bfa); }
.track-practice::before { background: linear-gradient(90deg, #06b6d4, #67e8f9); }

.track-creative { border-color: rgba(124, 58, 237, .35); box-shadow: 0 10px 30px rgba(124, 58, 237, .12); }
.track-practice { border-color: rgba(6, 182, 212, .35); box-shadow: 0 10px 30px rgba(6, 182, 212, .12); }

.track-icon { font-size: 2.2rem; }
.track-card h3 { margin-top: 10px; font-size: 1.5rem; font-weight: 900; letter-spacing: -0.02em; }
.track-creative h3 { color: #6d28d9; }
.track-practice h3 { color: #0891b2; }
.track-desc { margin: 10px 0 18px; color: var(--c-ink-soft); }

.track-list li {
  position: relative;
  padding: 9px 0 9px 30px;
  border-top: 1px dashed rgba(124, 58, 237, .14);
  color: var(--c-ink-soft);
  font-size: .97rem;
}
.track-list li::before {
  content: "✦";
  position: absolute;
  left: 6px;
  color: var(--c-primary);
}
.track-practice .track-list li::before { color: var(--c-cyan); }

.tracks-note {
  margin-top: 30px;
  text-align: center;
  font-size: 1.05rem;
  color: var(--c-ink-soft);
}
.tracks-note strong { color: var(--c-primary); }

/* =====================================================
   5. 赛程时间轴
   ===================================================== */
.timeline { position: relative; max-width: 720px; margin: 0 auto; }

.timeline-group { position: relative; padding-left: 34px; }
.timeline-group + .timeline-group { margin-top: 44px; }

/* 渐变竖线 */
.timeline::before {
  content: "";
  position: absolute;
  top: 8px; bottom: 8px;
  left: 10px;
  width: 4px;
  border-radius: 4px;
  background: var(--grad-main);
  opacity: .85;
}

.timeline-group-title {
  position: relative;
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 20px;
  font-size: 1.3rem;
  font-weight: 900;
  letter-spacing: -0.01em;
}
.group-dot {
  position: absolute;
  left: -34px;
  width: 24px; height: 24px;
  border-radius: 50%;
  background: var(--grad-main);
  border: 5px solid var(--c-bg);
  box-shadow: 0 0 0 2px rgba(124, 58, 237, .25);
}

.timeline-list { display: flex; flex-direction: column; gap: 14px; }

.timeline-item {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  padding: 18px 20px;
  background: var(--c-card);
  border: 1px solid var(--c-border);
  border-radius: 18px;
  box-shadow: var(--shadow-card);
  transition: transform .3s ease, box-shadow .3s ease;
}
.timeline-item:hover { transform: translateY(-3px); box-shadow: var(--shadow-card-hover); }

.date-badge {
  flex: 0 0 auto;
  min-width: 92px;
  text-align: center;
  padding: 7px 12px;
  border-radius: 12px;
  background: var(--grad-soft);
  border: 1px solid rgba(124, 58, 237, .2);
  color: var(--c-primary);
  font-weight: 900;
  font-variant-numeric: tabular-nums;
  font-size: .95rem;
  letter-spacing: .01em;
}
.timeline-body h4 { font-size: 1.08rem; font-weight: 800; letter-spacing: -0.01em; }
.timeline-body p { margin-top: 4px; color: var(--c-ink-soft); font-size: .93rem; }
.timeline-body em { font-style: normal; color: var(--c-pink); font-weight: 700; }

/* =====================================================
   6. 评委
   ===================================================== */
.judges-grid { margin-bottom: 24px; }

.judge-card { text-align: center; }
.judge-avatar {
  width: 76px; height: 76px;
  margin: 0 auto 16px;
  display: grid;
  place-items: center;
  font-size: 2.2rem;
  border-radius: 50%;
  background: var(--grad-soft);
  border: 1px solid rgba(124, 58, 237, .16);
}
.judge-card h3 { font-size: 1.2rem; font-weight: 800; }
.badge-mini {
  display: inline-block;
  margin-left: 6px;
  padding: 2px 9px;
  border-radius: 999px;
  font-size: .68rem;
  font-weight: 700;
  vertical-align: middle;
  color: var(--c-pink);
  background: rgba(236, 72, 153, .1);
  border: 1px solid rgba(236, 72, 153, .3);
  letter-spacing: .05em;
}
.judge-role {
  margin-top: 4px;
  font-size: .86rem;
  font-weight: 700;
  background: var(--grad-main);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.judge-card p:last-child { margin-top: 8px; color: var(--c-ink-soft); font-size: .93rem; }

/* AI 开发要求卡 */
.rule-card {
  border: 1.5px dashed rgba(124, 58, 237, .35);
  background: linear-gradient(135deg, rgba(124, 58, 237, .05), rgba(6, 182, 212, .05));
}
.rule-head { display: flex; align-items: center; gap: 10px; margin-bottom: 14px; }
.rule-icon { font-size: 1.5rem; }
.rule-card h3 { font-size: 1.25rem; font-weight: 900; letter-spacing: -0.01em; }
.rule-list li {
  position: relative;
  padding: 7px 0 7px 28px;
  color: var(--c-ink-soft);
  font-size: .97rem;
}
.rule-list li::before {
  content: "✓";
  position: absolute;
  left: 2px;
  font-weight: 900;
  color: var(--c-primary);
}

/* =====================================================
   7. 奖项
   ===================================================== */
.awards-track-note {
  margin-bottom: 22px;
  text-align: center;
  color: var(--c-ink-soft);
}
.awards-track-note strong { color: var(--c-primary); }

.award-card { text-align: center; position: relative; overflow: hidden; }
.award-card::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 6px;
}
.award-gold::before { background: linear-gradient(90deg, #f59e0b, #fbbf24, #f59e0b); }
.award-gold { border-color: rgba(245, 158, 11, .4); }
.award-gold h3 {
  background: linear-gradient(135deg, #b45309, #f59e0b, #d97706);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.award-silver::before { background: linear-gradient(90deg, #94a3b8, #cbd5e1, #94a3b8); }
.award-silver { border-color: rgba(148, 163, 184, .45); }
.award-silver h3 {
  background: linear-gradient(135deg, #475569, #94a3b8);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.award-bronze::before { background: linear-gradient(90deg, #ea580c, #fb923c); }
.award-bronze { border-color: rgba(234, 88, 12, .35); }
.award-bronze h3 {
  background: linear-gradient(135deg, #9a3412, #ea580c);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.award-medal { font-size: 2.4rem; }
.award-card h3 { font-size: 1.45rem; font-weight: 900; letter-spacing: -0.02em; }
.award-count {
  margin-top: 8px;
  display: inline-block;
  padding: 4px 14px;
  border-radius: 999px;
  background: var(--c-bg);
  border: 1px solid var(--c-border);
  font-size: .85rem;
  font-weight: 700;
  color: var(--c-ink-soft);
}
.award-desc { margin-top: 12px; color: var(--c-ink-soft); font-weight: 600; }

/* 单项奖 */
.special-awards { margin-top: 24px; }
.special-card {
  display: flex;
  align-items: center;
  gap: 18px;
  padding: 26px 28px;
}
.special-emoji {
  flex: 0 0 auto;
  width: 58px; height: 58px;
  display: grid;
  place-items: center;
  font-size: 1.7rem;
  border-radius: 16px;
  background: var(--grad-soft);
  border: 1px solid rgba(124, 58, 237, .16);
}
.special-card h3 { font-size: 1.15rem; font-weight: 800; }
.special-card p { margin-top: 4px; color: var(--c-ink-soft); font-size: .93rem; }

/* 完赛福利条 */
.perk-bar {
  margin-top: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 14px 22px;
  padding: 20px 26px;
  border-radius: var(--radius-md);
  background: var(--grad-soft);
  border: 1px solid rgba(124, 58, 237, .16);
  text-align: center;
  color: var(--c-ink-soft);
  font-size: .96rem;
}
.perk-divider {
  width: 1px;
  height: 22px;
  background: rgba(124, 58, 237, .25);
}

/* =====================================================
   8. FAQ 手风琴
   ===================================================== */
.faq-list { display: flex; flex-direction: column; gap: 14px; }

.faq-item {
  background: var(--c-card);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-card);
  overflow: hidden;
  transition: box-shadow .3s ease;
}
.faq-item:hover { box-shadow: var(--shadow-card-hover); }
.faq-item[open] { border-color: rgba(124, 58, 237, .35); }

.faq-item summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  padding: 19px 22px;
  cursor: pointer;
  font-weight: 800;
  font-size: 1.02rem;
  letter-spacing: -0.01em;
  list-style: none;
  user-select: none;
}
.faq-item summary::-webkit-details-marker { display: none; }

.faq-arrow {
  flex: 0 0 auto;
  width: 30px; height: 30px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: var(--grad-soft);
  color: var(--c-primary);
  font-size: .85rem;
  transition: transform .3s ease;
}
.faq-item[open] .faq-arrow { transform: rotate(180deg); }

.faq-a {
  padding: 0 22px 20px;
  color: var(--c-ink-soft);
  font-size: .96rem;
}
.faq-a p { border-top: 1px dashed var(--c-border); padding-top: 14px; }

/* =====================================================
   9. 报名大区块
   ===================================================== */
.signup-section { padding-bottom: 100px; }

.signup-box {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 40px;
  padding: 60px 56px;
  border-radius: 32px;
  background: var(--grad-main);
  color: #fff;
  box-shadow: 0 24px 60px rgba(94, 62, 181, .35);
  position: relative;
  overflow: hidden;
}
/* 渐变底上的柔和光斑 */
.signup-box::before,
.signup-box::after {
  content: "";
  position: absolute;
  border-radius: 50%;
  background: rgba(255, 255, 255, .14);
  filter: blur(60px);
  pointer-events: none;
}
.signup-box::before { width: 300px; height: 300px; top: -120px; right: -60px; }
.signup-box::after { width: 240px; height: 240px; bottom: -110px; left: -60px; }

.signup-info { position: relative; z-index: 1; max-width: 520px; }

.signup-badge {
  display: inline-block;
  padding: 6px 16px;
  border-radius: 999px;
  background: rgba(255, 255, 255, .16);
  border: 1px solid rgba(255, 255, 255, .35);
  font-size: .78rem;
  font-weight: 800;
  letter-spacing: .22em;
}
.signup-title {
  margin-top: 16px;
  font-size: clamp(1.8rem, 4.5vw, 2.5rem);
  font-weight: 900;
  letter-spacing: -0.02em;
}
.signup-sub { margin-top: 12px; font-size: 1.05rem; opacity: .95; }
.signup-info .btn { margin-top: 26px; }
.signup-contact { margin-top: 18px; font-size: .9rem; opacity: .85; }

.signup-qr {
  position: relative;
  z-index: 1;
  text-align: center;
  flex: 0 0 auto;
}
.qr-placeholder {
  width: 168px;
  height: 168px;
  display: grid;
  place-items: center;
  align-content: center;
  gap: 6px;
  border: 2px dashed rgba(255, 255, 255, .6);
  border-radius: 20px;
  background: rgba(255, 255, 255, .08);
  font-size: 1.6rem;
  letter-spacing: .1em;
}
.qr-placeholder p { font-size: .9rem; font-weight: 700; letter-spacing: .08em; }
.qr-tip { margin-top: 12px; font-size: .88rem; opacity: .9; }

/* =====================================================
   10. 页脚
   ===================================================== */
.footer {
  padding: 34px 0 40px;
  border-top: 1px solid var(--c-border);
  text-align: center;
  background: rgba(255, 255, 255, .6);
}
.footer p { font-weight: 700; letter-spacing: .02em; }
.footer-small { margin-top: 6px; font-size: .86rem; font-weight: 500; color: var(--c-muted); }

/* =====================================================
   动效：渐入
   ===================================================== */
.reveal {
  opacity: 0;
  transform: translateY(26px);
  transition: opacity .7s ease, transform .7s ease;
}
.reveal.visible { opacity: 1; transform: none; }

/* =====================================================
   响应式
   ===================================================== */
@media (max-width: 900px) {
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
  .signup-box { flex-direction: column; text-align: center; padding: 48px 32px; }
  .signup-info { max-width: 100%; }
}

@media (max-width: 680px) {
  .section { padding: 64px 0; }
  .hero { padding-top: 64px; padding-bottom: 64px; }
  .grid-3, .grid-2 { grid-template-columns: 1fr; }

  /* 手机端导航折叠 */
  .nav-toggle { display: flex; }
  .nav-links {
    position: absolute;
    top: var(--nav-h);
    left: 0; right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 4px;
    padding: 12px 20px 18px;
    background: rgba(255, 255, 255, .96);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--c-border);
    box-shadow: 0 16px 32px rgba(94, 62, 181, .12);
    display: none;
  }
  .nav-links.open { display: flex; }
  .nav-links > a:not(.btn) { padding: 12px 4px; border-bottom: 1px dashed var(--c-border); }
  .nav-links > a:not(.btn)::after { display: none; }
  .btn-nav { margin-top: 12px; justify-content: center; }

  .cd-num { min-width: 56px; font-size: 1.7rem; }
  .cd-sep { padding-bottom: 22px; font-size: 1.3rem; }

  .timeline-group { padding-left: 26px; }
  .timeline::before { left: 7px; width: 3px; }
  .group-dot { left: -26px; width: 19px; height: 19px; border-width: 4px; }

  .timeline-item { flex-direction: column; gap: 10px; padding: 16px; }
  .date-badge { align-self: flex-start; min-width: 0; }

  .perk-bar { flex-direction: column; }
  .perk-divider { width: 44px; height: 1px; }

  .signup-box { padding: 40px 22px; }
  .qr-placeholder { width: 150px; height: 150px; margin: 0 auto; }
}

/* 极小屏（如 320px）兜底 */
@media (max-width: 360px) {
  .hero-actions .btn { width: 100%; }
  .cd-num { min-width: 46px; padding: 8px 4px; font-size: 1.4rem; }
  .cd-sep { display: none; }
  .countdown { gap: 6px; }
}

/* =====================================================
   无障碍：减弱动效
   ===================================================== */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .01ms !important;
  }
  .reveal { opacity: 1; transform: none; }
}

/* =====================================================
   多页站点追加公共样式（沿用原有变量与视觉方向）
   导航 active 态 / 赛道卡详情链接 / 关键日期速览条 /
   三步参赛流程 / 首页底部 CTA 条
   ===================================================== */

/* ---------- 导航当前页高亮 ---------- */
.nav-links > a:not(.btn).active { color: var(--c-primary); }
.nav-links > a:not(.btn).active::after { transform: scaleX(1); }

/* ---------- 首页赛道卡"查看详情"链接 ---------- */
.track-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: 18px;
  font-weight: 800;
  color: var(--c-primary);
}
.track-link::after {
  content: "→";
  transition: transform .25s ease;
}
.track-link:hover::after { transform: translateX(4px); }
.track-practice .track-link { color: var(--c-cyan); }

/* ---------- 赛程页：关键日期速览条 ---------- */
.key-dates {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 14px;
  margin-bottom: 60px;
}
.key-date {
  flex: 1 1 150px;
  max-width: 200px;
  padding: 20px 12px 16px;
  text-align: center;
  background: var(--c-card);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-card);
  transition: transform .3s ease, box-shadow .3s ease;
}
.key-date:hover { transform: translateY(-4px); box-shadow: var(--shadow-card-hover); }
.key-date .date-badge { display: inline-block; }
.key-date-label {
  margin-top: 10px;
  font-size: .88rem;
  font-weight: 700;
  color: var(--c-ink-soft);
}

/* ---------- 报名页：三步参赛流程 ---------- */
.steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.step-card { text-align: center; }
.step-num {
  width: 46px; height: 46px;
  margin: 0 auto 14px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: var(--grad-main);
  color: #fff;
  font-weight: 900;
  font-size: 1.15rem;
  box-shadow: 0 8px 20px rgba(124, 58, 237, .32);
}
.step-card h3 { font-size: 1.15rem; font-weight: 800; letter-spacing: -0.01em; }
.step-card p { margin-top: 8px; color: var(--c-ink-soft); font-size: .95rem; }

/* ---------- 首页底部 CTA 条 ---------- */
.cta-banner {
  position: relative;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  padding: 56px 32px;
  border-radius: 32px;
  background: var(--grad-main);
  color: #fff;
  text-align: center;
  box-shadow: 0 24px 60px rgba(94, 62, 181, .35);
}
.cta-banner::before {
  content: "";
  position: absolute;
  width: 300px; height: 300px;
  top: -120px; right: -60px;
  border-radius: 50%;
  background: rgba(255, 255, 255, .14);
  filter: blur(60px);
  pointer-events: none;
}
.cta-banner h2,
.cta-banner p,
.cta-banner .btn { position: relative; z-index: 1; }
.cta-banner h2 {
  font-size: clamp(1.7rem, 4vw, 2.3rem);
  font-weight: 900;
  letter-spacing: -0.02em;
}
.cta-banner p { opacity: .95; }
.cta-banner strong { color: #fff; }
.cta-banner .btn { margin-top: 10px; }

/* ---------- 追加样式的响应式 ---------- */
@media (max-width: 680px) {
  .key-dates { gap: 10px; margin-bottom: 44px; }
  .key-date { flex: 1 1 140px; }
  .steps { grid-template-columns: 1fr; }
  .cta-banner { padding: 44px 24px; }
}

/* =====================================================
   results 页追加样式（获奖名单占位 / 作品展示骨架）
   仅新增，不修改上方已有样式
   ===================================================== */

/* ---------- 状态卡 ---------- */
.status-card {
  max-width: 620px;
  margin: 0 auto;
  padding: 30px 28px;
  background: var(--c-card);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
  text-align: center;
}
.status-line {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  font-weight: 700;
  color: var(--c-ink-soft);
}
.status-pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  border-radius: 999px;
  background: var(--grad-soft);
  border: 1px solid rgba(124, 58, 237, .25);
  color: var(--c-primary);
  font-weight: 800;
}
.status-dot {
  width: 9px; height: 9px;
  border-radius: 50%;
  background: #f59e0b;
  box-shadow: 0 0 0 4px rgba(245, 158, 11, .18);
  animation: status-pulse 1.6s ease-in-out infinite;
}
@keyframes status-pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: .45; }
}
.status-text { margin-top: 14px; color: var(--c-ink-soft); }
.status-date { font-weight: 900; font-size: 1.06em; }

/* ---------- 区块小标题 ---------- */
.results-subhead {
  margin: 68px 0 26px;
  text-align: center;
  font-size: 1.45rem;
  font-weight: 900;
  letter-spacing: -0.02em;
}

/* ---------- 获奖名单占位行 ---------- */
.result-list { margin-top: 16px; }
.result-row {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 2px;
  border-top: 1px dashed rgba(124, 58, 237, .16);
  color: var(--c-ink-soft);
  font-size: .97rem;
}
.result-medal { font-size: 1.25rem; }
.result-name { font-weight: 700; }
.result-pending {
  margin-left: auto;
  padding: 3px 12px;
  border-radius: 999px;
  font-size: .8rem;
  font-weight: 700;
  color: var(--c-muted);
  background: var(--c-bg);
  border: 1px dashed rgba(124, 58, 237, .28);
  white-space: nowrap;
}
.track-practice .result-row { border-top-color: rgba(6, 182, 212, .22); }
.track-practice .result-pending { border-color: rgba(6, 182, 212, .32); }

/* ---------- 作品展示占位 ---------- */
.showcase-box {
  padding: 34px 28px;
  border: 1.5px dashed rgba(124, 58, 237, .32);
  border-radius: var(--radius-lg);
  background: linear-gradient(135deg, rgba(124, 58, 237, .04), rgba(6, 182, 212, .04));
}
.showcase-note {
  max-width: 620px;
  margin: 0 auto 26px;
  text-align: center;
  color: var(--c-ink-soft);
}
.work-card { text-align: left; }
.work-thumb {
  height: 150px;
  display: grid;
  place-items: center;
  border-radius: 14px;
  background: linear-gradient(135deg, #ececf4, #dcdeea);
  border: 1px dashed rgba(124, 58, 237, .22);
  color: var(--c-muted);
  font-size: .85rem;
  font-weight: 700;
  letter-spacing: .05em;
}
.work-name { margin-top: 14px; font-size: 1.1rem; font-weight: 800; }
.work-team { margin-top: 4px; color: var(--c-muted); font-size: .9rem; }
.work-btn {
  margin-top: 14px;
  padding: 9px 20px;
  font-size: .9rem;
  background: linear-gradient(135deg, #e8e9f1, #dcdeea);
  color: var(--c-muted);
  border: 1px solid rgba(124, 58, 237, .12);
  cursor: not-allowed;
}
.work-btn:hover { transform: none; }
.work-btn:active { transform: none; }

/* ---------- results 页响应式 ---------- */
@media (max-width: 680px) {
  .status-card { padding: 24px 18px; }
  .results-subhead { margin: 48px 0 22px; }
  .showcase-box { padding: 26px 16px; }
}

/* ==========================================================
   作品帖社区（works showcase v2）
   ========================================================== */
.work-toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin-bottom: 26px;
}
.work-toolbar .work-post-btn {
  margin-left: auto;
  padding: 8px 18px;
  font-size: .9rem;
}
/* 发帖账号说明条 */
.account-note {
  margin-bottom: 22px;
  padding: 16px 20px;
  border-radius: 14px;
  border: 1px solid rgba(124, 58, 237, .18);
  background: rgba(124, 58, 237, .06);
}
.account-note .account-line {
  margin: 0;
  font-size: .92rem;
  line-height: 1.7;
  color: var(--c-ink-soft);
}
.account-note .account-line + .account-line { margin-top: 6px; }
.account-note strong { color: var(--c-main); }
@media (max-width: 680px) {
  .work-toolbar .work-post-btn { margin-left: 0; }
}
.work-filter {
  padding: 8px 18px;
  border-radius: 999px;
  border: 1px solid rgba(124, 58, 237, .25);
  background: rgba(124, 58, 237, .05);
  color: var(--c-muted);
  font-weight: 700;
  font-size: .9rem;
  cursor: pointer;
  transition: all .2s;
}
.work-filter:hover { border-color: var(--c-main); color: var(--c-main); }
.work-filter.is-active {
  background: var(--grad-main);
  color: #fff;
  border-color: transparent;
  box-shadow: 0 6px 16px rgba(124, 58, 237, .3);
}
.work-card { display: flex; flex-direction: column; position: relative; }
.work-card .work-thumb {
  border-radius: 14px;
  height: 150px;
  display: grid;
  place-items: center;
  font-size: 2.6rem;
  color: transparent;
  text-shadow: none;
}
.work-card .work-thumb.thumb-sun { background: linear-gradient(135deg, #ffb347, #ff7e5f); }
.work-card .work-thumb.thumb-leaf { background: linear-gradient(135deg, #43cea2, #185a9d); }
.work-card .work-thumb.thumb-sky { background: linear-gradient(135deg, #7f7fd5, #91eae4); }
.work-card .work-thumb.thumb-violet { background: linear-gradient(135deg, #a18cd1, #fbc2eb); }
.work-card .work-thumb.thumb-night { background: linear-gradient(135deg, #2b5876, #4e4376); }
.work-card .work-thumb.thumb-candy { background: linear-gradient(135deg, #f78ca0, #f9748f); }
.work-badge {
  position: absolute;
  top: 14px; left: 14px;
  padding: 4px 12px;
  border-radius: 999px;
  font-size: .75rem;
  font-weight: 800;
  color: #fff;
  backdrop-filter: blur(6px);
  background: rgba(0, 0, 0, .28);
}
.work-badge.b-creative { background: rgba(255, 126, 95, .92); }
.work-badge.b-practice { background: rgba(24, 90, 157, .92); }
.work-desc { margin-top: 8px; color: var(--c-muted); font-size: .92rem; line-height: 1.6; flex: 1; }
.work-meta { margin-top: 10px; display: flex; gap: 8px; flex-wrap: wrap; }
.work-meta span {
  font-size: .75rem;
  padding: 3px 10px;
  border-radius: 8px;
  background: rgba(124, 58, 237, .08);
  color: var(--c-main);
  font-weight: 700;
}
.work-card .work-btn {
  margin-top: 16px;
  text-align: center;
  background: var(--grad-main);
  color: #fff;
  border: none;
  cursor: pointer;
  box-shadow: 0 6px 16px rgba(124, 58, 237, .3);
}
.demo-note {
  margin-top: 18px;
  text-align: center;
  color: var(--c-muted);
  font-size: .88rem;
}

/* ---------- 作品帖详情页 ---------- */
.post-hero {
  border-radius: 20px;
  height: 240px;
  display: grid;
  place-items: center;
  font-size: 4rem;
  box-shadow: var(--shadow);
}
.post-badges { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 22px; }
.post-badges span {
  padding: 5px 14px;
  border-radius: 999px;
  font-size: .8rem;
  font-weight: 800;
  color: #fff;
}
.post-badges .pb-track { background: var(--grad-main); }
.post-badges .pb-demo { background: linear-gradient(135deg, #f59e0b, #f97316); }
.post-title { margin-top: 16px; font-size: 2rem; font-weight: 900; letter-spacing: -0.02em; }
.post-team { margin-top: 10px; color: var(--c-muted); font-size: 1rem; }
.post-cta { margin-top: 24px; display: flex; gap: 14px; flex-wrap: wrap; }
.post-body { margin-top: 40px; max-width: 860px; }
.post-body h3 {
  margin: 34px 0 14px;
  font-size: 1.3rem;
  font-weight: 800;
  display: flex;
  align-items: center;
  gap: 10px;
}
.post-body h3::before {
  content: "";
  width: 6px; height: 22px;
  border-radius: 3px;
  background: var(--grad-main);
}
.post-body p { line-height: 1.9; color: var(--c-ink-soft, #444); margin-bottom: 10px; }
.post-body ul { margin: 8px 0 8px 4px; list-style: none; }
.post-body ul li {
  position: relative;
  padding-left: 26px;
  line-height: 1.9;
  color: var(--c-ink-soft, #444);
  margin-bottom: 6px;
}
.post-body ul li::before {
  content: "✦";
  position: absolute;
  left: 2px;
  color: var(--c-main);
  font-size: .85rem;
}
.post-shot {
  border-radius: 14px;
  height: 190px;
  margin: 14px 0;
  display: grid;
  place-items: center;
  color: rgba(255, 255, 255, .85);
  font-weight: 800;
  letter-spacing: .08em;
}
.post-nav {
  margin-top: 56px;
  padding-top: 26px;
  border-top: 1px solid rgba(124, 58, 237, .12);
  display: flex;
  justify-content: space-between;
  gap: 14px;
  flex-wrap: wrap;
}
.post-nav a {
  padding: 12px 20px;
  border-radius: 12px;
  border: 1px solid rgba(124, 58, 237, .2);
  font-weight: 700;
  font-size: .92rem;
  color: var(--c-ink, #222);
  transition: all .2s;
}
.post-nav a:hover { border-color: var(--c-main); color: var(--c-main); transform: translateY(-2px); }
.back-list { display: inline-block; margin-bottom: 26px; color: var(--c-muted); font-weight: 700; font-size: .92rem; }
.back-list:hover { color: var(--c-main); }

@media (max-width: 680px) {
  .post-hero { height: 170px; font-size: 2.6rem; }
  .post-title { font-size: 1.5rem; }
}