/* ========= 基础变量 ========= */
:root {
  --bg: #F4F7FB;
  --ink: #0F172A;
  --ink-soft: #475569;
  --muted: #94A3B8;
  --line: #E2E8F0;
  --white: #ffffff;
  --shadow-sm: 0 4px 12px rgba(15, 23, 42, .06);
  --shadow-md: 0 10px 30px rgba(15, 23, 42, .08);
  --shadow-lg: 0 20px 60px rgba(15, 23, 42, .15);
  --radius: 16px;
  --radius-lg: 22px;
  --c-blue: #3B82F6;
  --c-blue-bg: #EFF6FF;
  --c-green: #10B981;
  --c-green-bg: #ECFDF5;
  --c-orange: #F97316;
  --c-orange-bg: #FFF7ED;
  --c-purple: #A855F7;
  --c-purple-bg: #F5F3FF;
  --c-yellow: #F59E0B;
}

* { box-sizing: border-box; }
html, body {
  margin: 0; padding: 0;
  font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, "Hiragino Sans GB", "Heiti SC", sans-serif;
  color: var(--ink);
  background:
    radial-gradient(1200px 600px at 10% -10%, rgba(59, 130, 246, .08), transparent 60%),
    radial-gradient(900px 500px at 110% 10%, rgba(168, 85, 247, .10), transparent 60%),
    var(--bg);
  -webkit-font-smoothing: antialiased;
  line-height: 1.6;
}
.container { max-width: 1180px; margin: 0 auto; padding: 0 24px; }
h1, h2, h3, h4 { margin: 0; line-height: 1.3; }

/* ========= 顶部条 ========= */
.top-bars {
  display: flex; gap: 8px; padding: 16px 24px 0;
  max-width: 1180px; margin: 0 auto;
}
.top-bars span { flex: 1; height: 4px; border-radius: 4px; opacity: .75; }

/* ========= 头部 ========= */
.hero {
  padding: 32px 0 40px;
}
.hero-inner {
  max-width: 1180px; margin: 0 auto; padding: 0 24px;
}
.badge-pill {
  display: inline-block;
  padding: 6px 14px;
  background: var(--c-blue);
  color: #fff;
  border-radius: 999px;
  font-size: 13px;
  letter-spacing: .5px;
  box-shadow: 0 4px 10px rgba(59,130,246,.25);
}
.hero h1 {
  font-size: clamp(32px, 5vw, 56px);
  font-weight: 800;
  letter-spacing: -1px;
  margin: 18px 0 12px;
}
.accent {
  background: linear-gradient(120deg, #3B82F6 0%, #A855F7 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.hero-sub {
  font-size: 17px;
  color: var(--ink-soft);
  max-width: 700px;
  margin: 0 0 30px;
}
.hero-sub strong { color: var(--ink); }

.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 16px;
}
.stat-card {
  background: var(--white);
  border-radius: var(--radius);
  padding: 22px 24px;
  box-shadow: var(--shadow-sm);
  border: 1px solid rgba(15,23,42,.04);
  display: flex; flex-direction: column; gap: 4px;
}
.stat-num {
  font-size: 30px; font-weight: 800;
  background: linear-gradient(90deg, #3B82F6, #A855F7);
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.stat-label { color: var(--ink-soft); font-size: 13px; }

/* ========= 模块卡片 ========= */
.modules-row {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 16px;
  margin-bottom: 36px;
}
.mod-card {
  display: flex; align-items: center; gap: 14px;
  background: var(--white);
  border-radius: var(--radius);
  padding: 18px;
  border: 1px solid rgba(15,23,42,.04);
  box-shadow: var(--shadow-sm);
  cursor: pointer;
  transition: transform .2s ease, box-shadow .2s ease;
}
.mod-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); }
.mod-card .mod-num {
  width: 42px; height: 42px;
  border-radius: 12px;
  display: grid; place-items: center;
  font-weight: 800; color: #fff;
  background: var(--c-blue);
  font-size: 18px;
  flex: 0 0 auto;
}
.mod-card[data-mod="tool"] .mod-num { background: var(--c-blue); }
.mod-card[data-mod="study"] .mod-num { background: var(--c-green); }
.mod-card[data-mod="prod"] .mod-num { background: var(--c-orange); }
.mod-card.future .mod-num { background: var(--c-purple); }
.mod-meta h3 { font-size: 16px; margin-bottom: 4px; }
.mod-meta p { margin: 0 0 8px; font-size: 13px; color: var(--ink-soft); }
.chip {
  display: inline-block;
  padding: 3px 10px;
  font-size: 12px;
  border-radius: 999px;
  background: #F1F5F9;
  color: var(--ink-soft);
}
.mod-card[data-mod="tool"] .chip { background: var(--c-blue-bg); color: var(--c-blue); }
.mod-card[data-mod="study"] .chip { background: var(--c-green-bg); color: var(--c-green); }
.mod-card[data-mod="prod"] .chip { background: var(--c-orange-bg); color: var(--c-orange); }
.mod-card.future .chip { background: var(--c-purple-bg); color: var(--c-purple); }

/* ========= 课程列表 ========= */
.course-list-section { padding-bottom: 60px; }
.section-head {
  display: flex; align-items: center; justify-content: space-between;
  margin: 20px 0 20px;
  flex-wrap: wrap; gap: 12px;
}
.section-head h2 { font-size: 26px; }
.filters {
  display: flex; gap: 6px; flex-wrap: wrap;
}
.filter-btn {
  border: 1px solid var(--line);
  background: var(--white);
  border-radius: 999px;
  padding: 8px 14px;
  font: inherit;
  font-size: 13px;
  cursor: pointer;
  color: var(--ink-soft);
  display: inline-flex; align-items: center; gap: 8px;
  transition: all .2s ease;
}
.filter-btn:hover { border-color: #CBD5E1; }
.filter-btn.active {
  background: var(--ink); color: #fff; border-color: var(--ink);
}
.filter-btn .dot { width: 8px; height: 8px; border-radius: 999px; display: inline-block; }
.dot-blue { background: var(--c-blue); }
.dot-green { background: var(--c-green); }
.dot-orange { background: var(--c-orange); }
.dot-purple { background: var(--c-purple); }

.course-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(290px, 1fr));
  gap: 16px;
}
.course-card {
  position: relative;
  background: var(--white);
  border-radius: var(--radius);
  padding: 18px 18px 16px;
  border: 1px solid rgba(15,23,42,.05);
  box-shadow: var(--shadow-sm);
  cursor: pointer;
  transition: all .25s ease;
  overflow: hidden;
  display: flex; flex-direction: column; gap: 8px;
  min-height: 168px;
}
.course-card::before {
  content: ""; position: absolute; left: 0; top: 0; bottom: 0; width: 4px;
  background: var(--c-blue);
}
.course-card[data-mod="tool"]::before { background: var(--c-blue); }
.course-card[data-mod="study"]::before { background: var(--c-green); }
.course-card[data-mod="prod"]::before { background: var(--c-orange); }
.course-card[data-mod="future"]::before { background: var(--c-purple); }
.course-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: rgba(15,23,42,.08);
}
.course-card .cc-head {
  display: flex; align-items: center; justify-content: space-between;
  font-size: 12px;
}
.cc-no {
  background: #F1F5F9;
  color: var(--ink-soft);
  padding: 3px 8px;
  border-radius: 6px;
  font-weight: 600;
  font-feature-settings: "tnum";
}
.course-card[data-mod="tool"] .cc-no { background: var(--c-blue-bg); color: var(--c-blue); }
.course-card[data-mod="study"] .cc-no { background: var(--c-green-bg); color: var(--c-green); }
.course-card[data-mod="prod"] .cc-no { background: var(--c-orange-bg); color: var(--c-orange); }
.course-card[data-mod="future"] .cc-no { background: var(--c-purple-bg); color: var(--c-purple); }

.cc-mod {
  color: var(--muted);
  font-size: 12px;
}
.cc-title {
  font-size: 17px; font-weight: 700; color: var(--ink);
  line-height: 1.4;
}
.cc-summary {
  font-size: 13px;
  color: var(--ink-soft);
  flex: 1;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.cc-foot {
  display: flex; align-items: center; justify-content: space-between;
  font-size: 12px;
  color: var(--ink-soft);
  margin-top: 8px;
}
.cc-cta {
  background: rgba(15,23,42,.05);
  color: var(--ink);
  padding: 4px 10px;
  border-radius: 999px;
  font-weight: 600;
  transition: all .2s ease;
}
.course-card:hover .cc-cta {
  background: var(--ink); color: #fff;
}
a.cc-slides {
  text-decoration: none;
  background: var(--c-blue-bg); color: var(--c-blue);
  padding: 4px 10px;
  border-radius: 999px;
  font-weight: 600;
  font-size: 12px;
  transition: all .2s ease;
}
.course-card:hover a.cc-slides {
  background: var(--c-blue); color: #fff;
}

/* ========= 弹层 ========= */
.modal-mask {
  position: fixed; inset: 0;
  background: rgba(15, 23, 42, .55);
  backdrop-filter: blur(4px);
  display: none;
  align-items: flex-start;
  justify-content: center;
  padding: 60px 24px;
  z-index: 99;
  overflow-y: auto;
}
.modal-mask.open { display: flex; animation: fadeIn .2s ease; }
.modal {
  position: relative;
  background: var(--white);
  width: 100%;
  max-width: 760px;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
  animation: rise .25s ease;
}
.modal-close {
  position: absolute; top: 16px; right: 16px;
  width: 36px; height: 36px; border-radius: 999px;
  border: none; background: rgba(15,23,42,.06);
  font-size: 22px; cursor: pointer;
  color: var(--ink-soft);
  transition: background .15s ease;
  z-index: 2;
}
.modal-close:hover { background: rgba(15,23,42,.12); color: var(--ink); }
.modal-head {
  padding: 32px 36px 24px;
  background: linear-gradient(120deg, rgba(59,130,246,.10), rgba(168,85,247,.10));
  border-bottom: 1px solid var(--line);
}
.modal-head.tool { background: linear-gradient(120deg, rgba(59,130,246,.16), rgba(59,130,246,.04)); }
.modal-head.study { background: linear-gradient(120deg, rgba(16,185,129,.16), rgba(16,185,129,.04)); }
.modal-head.prod { background: linear-gradient(120deg, rgba(249,115,22,.16), rgba(249,115,22,.04)); }
.modal-head.future { background: linear-gradient(120deg, rgba(168,85,247,.16), rgba(168,85,247,.04)); }

.modal-tag {
  display: inline-block;
  padding: 4px 10px;
  border-radius: 6px;
  background: rgba(15,23,42,.08);
  color: var(--ink);
  font-size: 12px;
  font-weight: 600;
  margin-bottom: 10px;
}
.modal-head h2 { font-size: 26px; margin-bottom: 6px; }
.modal-summary { color: var(--ink-soft); font-size: 14px; margin: 6px 0 16px; }
.modal-meta {
  display: flex; gap: 18px; flex-wrap: wrap;
  font-size: 13px; color: var(--ink-soft);
}
.modal-meta b { color: var(--ink); margin-right: 4px; }

.modal-body {
  padding: 24px 36px 32px;
}
.modal-body section { margin-bottom: 22px; }
.modal-body h4 {
  font-size: 15px;
  margin-bottom: 10px;
  color: var(--ink);
}
.modal-body .tip {
  background: linear-gradient(90deg, #FFFBEB, #FEF3C7);
  border-radius: var(--radius);
  padding: 16px 18px;
  border-left: 4px solid var(--c-yellow);
}
.modal-body .tip p { margin: 4px 0 0; color: #78350F; }
.styled-ul, .styled-ol { margin: 0; padding-left: 20px; }
.styled-ul li, .styled-ol li {
  margin: 4px 0;
  color: var(--ink-soft);
  font-size: 14px;
}
.styled-ol li::marker { color: var(--c-blue); font-weight: 700; }

@keyframes fadeIn { from { opacity: 0 } to { opacity: 1 } }
@keyframes rise { from { opacity: 0; transform: translateY(20px); } to { opacity: 1; transform: none; } }

/* ========= 页脚 ========= */
.site-foot {
  border-top: 1px solid var(--line);
  background: var(--white);
  padding: 24px 0 40px;
  margin-top: 30px;
}
.site-foot p { margin: 4px 0; text-align: center; color: var(--ink); font-weight: 600; }
.site-foot .muted { color: var(--muted); font-weight: 400; }

/* ========= 响应式 ========= */
@media (max-width: 900px) {
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .modules-row { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 560px) {
  .hero h1 { font-size: 32px; }
  .stats-grid { grid-template-columns: 1fr 1fr; }
  .modules-row { grid-template-columns: 1fr; }
  .modal-head, .modal-body { padding-left: 22px; padding-right: 22px; }
}