:root {
  --ink: #102033;
  --muted: #66758a;
  --line: #dce5ee;
  --accent: #0f8f72;
  --accent-dark: #076b55;
  --gold: #f3b23d;
  --paper: #f8fbfd;
  --white: #fff;
  font-family: "Microsoft YaHei", "PingFang SC", Arial, sans-serif;
}

* { box-sizing: border-box; }
body { margin: 0; color: var(--ink); background: var(--paper); }
a { color: inherit; text-decoration: none; }
button, input { font: inherit; }

.site-header {
  position: fixed;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  min-height: 76px;
  padding: 0 5vw;
  color: var(--white);
  transition: background .2s ease, border-color .2s ease, box-shadow .2s ease;
}
.site-header.solid { position: sticky; color: var(--white); background: rgba(12,28,46,.96); border-bottom: 1px solid rgba(255,255,255,.12); backdrop-filter: blur(14px); }
.site-header.scrolled { background: rgba(12,28,46,.96); border-bottom: 1px solid rgba(255,255,255,.12); box-shadow: 0 8px 28px rgba(5,16,29,.22); backdrop-filter: blur(14px); }
.brand { display: inline-flex; gap: 12px; align-items: center; min-width: 190px; }
.brand-logos { min-width: 310px; gap: 14px; }
.brand-logos img:first-child { width: 198px; max-height: 46px; object-fit: contain; }
.brand-logos img:last-child { width: 100px; max-height: 30px; object-fit: contain; }
.brand-divider { width: 1px; height: 34px; background: rgba(255,255,255,.38); }
.admin-brand { min-width: 0; flex-wrap: nowrap; gap: 10px; }
.admin-brand img:first-child { width: 132px; max-height: 34px; }
.admin-brand img:last-child { width: 72px; max-height: 24px; }
.admin-brand .brand-divider { height: 26px; }
.brand-mark {
  display: grid;
  width: 42px;
  height: 42px;
  place-items: center;
  border-radius: 10px;
  background: var(--accent);
  color: #fff;
  font-weight: 800;
}
.brand strong, .brand small { display: block; }
.brand small { margin-top: 2px; opacity: .78; font-size: 12px; }
.top-nav { display: flex; gap: 28px; font-size: 15px; }
.top-nav a { opacity: .9; }

.hero {
  position: relative;
  min-height: 454px;
  display: flex;
  align-items: center;
  padding: 98px 5vw 58px;
  color: #fff;
  background-image: url("/static/assets/images/hero-aigc.png");
  background-image: image-set(
    url("/static/assets/images/hero-aigc.webp") type("image/webp"),
    url("/static/assets/images/hero-aigc.png") type("image/png")
  );
  background-size: cover;
  background-position: center;
}
.hero-shade { position: absolute; inset: 0; background: linear-gradient(90deg, rgba(7,18,32,.92), rgba(7,18,32,.68) 46%, rgba(7,18,32,.16)); }
.hero-content { position: relative; width: min(680px, 92vw); animation: rise .7s ease both; }
.eyebrow { margin: 0 0 12px; color: var(--accent); font-size: 14px; font-weight: 800; letter-spacing: 0; }
.hero .eyebrow { color: #a9f5df; }
.hero-edition { margin-bottom: 24px; font-size: 22px; }
h1, h2, h3, p { margin-top: 0; }
.hero h1 { margin-bottom: 24px; font-size: clamp(34px, 4.8vw, 58px); line-height: 1.12; letter-spacing: 0; white-space: nowrap; }
.hero h2 { margin-bottom: 30px; color: #c6fff0; font-size: clamp(26px, 3.5vw, 40px); line-height: 1.16; }
.hero-copy { max-width: 560px; color: rgba(255,255,255,.86); font-size: 20px; line-height: 1.75; }
.hero-actions, .unlock-actions { display: flex; gap: 16px; align-items: center; flex-wrap: wrap; }
.primary-button, .ghost-button {
  border: 0;
  min-height: 44px;
  padding: 0 22px;
  border-radius: 8px;
  cursor: pointer;
  transition: transform .18s ease, box-shadow .18s ease, background .18s ease;
}
.primary-button { background: var(--accent); color: #fff; box-shadow: 0 12px 32px rgba(15,143,114,.24); }
.primary-button.as-link { display: inline-flex; align-items: center; }
.primary-button:hover, .ghost-button:hover { transform: translateY(-1px); }
.primary-button.small { min-height: 38px; padding: 0 16px; }
.primary-button.full { width: 100%; margin-top: 8px; }
.ghost-button { background: rgba(255,255,255,.16); color: inherit; border: 1px solid rgba(255,255,255,.42); }
.ghost-button.dark { background: #fff; color: var(--ink); border-color: var(--line); }
.text-link { color: #fff; border-bottom: 1px solid currentColor; }
.text-link.dark { color: var(--accent-dark); }
.hero-meta { display: flex; gap: 12px; flex-wrap: wrap; margin-top: 38px; }
.hero-meta span { padding: 10px 14px; border: 1px solid rgba(255,255,255,.28); border-radius: 8px; background: rgba(255,255,255,.12); }

.section { padding: 84px 5vw; }
.section-title { max-width: 760px; margin-bottom: 42px; }
.section-title h1, .section-title h2 { font-size: clamp(32px, 4vw, 54px); line-height: 1.14; }
.section-title.compact { margin-bottom: 24px; }
.course-preview { padding-top: 56px; }
.course-content-title { margin-bottom: 14px; font-size: clamp(38px, 4.5vw, 60px) !important; }
.course-content-copy { color: var(--muted); font-size: 20px; line-height: 1.7; }
.steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1px; background: var(--line); border: 1px solid var(--line); }
.steps div { padding: 34px; background: #fff; }
.steps strong { color: var(--gold); font-size: 32px; }
.steps p, .price-option p, .course-card p, .form-note { color: var(--muted); line-height: 1.7; }
.course-preview { background: linear-gradient(180deg, #f5fbff 0%, #eef7fb 100%); }
.center-action { margin-top: 28px; }

.pricing-band { display: grid; grid-template-columns: 1fr 1.1fr; gap: 42px; align-items: center; padding: 86px 5vw; background: #102033; color: #fff; }
.pricing-copy p:not(.eyebrow) { color: rgba(255,255,255,.72); line-height: 1.8; }
.pricing-options { display: grid; grid-template-columns: repeat(2, minmax(0,1fr)); gap: 18px; }
.price-option { padding: 30px; background: rgba(255,255,255,.08); border: 1px solid rgba(255,255,255,.18); border-radius: 8px; }
.price-option.recommended { background: #fff; color: var(--ink); }
.price-option span { color: var(--accent); font-weight: 800; }
.price { color: inherit !important; font-size: 38px; font-weight: 900; }

.plain-page { background: #eef4f8; }
.course-page { padding-top: 54px; }
.course-toolbar { display: flex; align-items: center; justify-content: space-between; gap: 16px; padding: 16px 0 28px; }
.student-status { color: var(--muted); }
.course-grid { display: grid; grid-template-columns: repeat(5, minmax(0, 1fr)); gap: 18px; }
.course-grid.five { grid-template-columns: repeat(5, minmax(0, 1fr)); }
.course-card {
  position: relative;
  min-height: 280px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  overflow: hidden;
  padding: 22px;
  color: #fff;
  background-color: #102033;
  background-image: var(--course-cover);
  background-size: cover;
  background-position: center;
  border: 0;
  border-radius: 8px;
  box-shadow: 0 14px 34px rgba(38, 77, 112, .13);
  transition: transform .18s ease, box-shadow .18s ease;
}
.course-card::before {
  content: "";
  position: absolute;
  inset: 0;
  display: block;
  background: rgba(8, 20, 34, .22);
  z-index: 0;
}
.course-card-bg, .course-cover { display: none; }
.course-card > * { position: relative; z-index: 1; }
.course-bg-1 { --course-a: rgba(30, 157, 132, .82); --course-b: rgba(20, 65, 117, .9); background-position: 8% 28%; }
.course-bg-2 { --course-a: rgba(76, 128, 255, .8); --course-b: rgba(33, 58, 134, .9); background-position: 34% 22%; }
.course-bg-3 { --course-a: rgba(242, 152, 74, .78); --course-b: rgba(36, 83, 140, .9); background-position: 55% 34%; }
.course-bg-4 { --course-a: rgba(139, 106, 238, .78); --course-b: rgba(38, 72, 132, .9); background-position: 74% 30%; }
.course-bg-5 { --course-a: rgba(41, 178, 214, .8); --course-b: rgba(21, 88, 113, .9); background-position: 92% 42%; }
.course-card:hover { transform: translateY(-3px); box-shadow: 0 20px 46px rgba(38, 77, 112, .18); }
.course-top { display: flex; justify-content: space-between; gap: 12px; }
.course-no { padding: 6px 9px; border-radius: 6px; background: rgba(255,255,255,.2); color: #fff; font-weight: 900; backdrop-filter: blur(8px); }
.badge { padding: 6px 9px; border-radius: 999px; background: rgba(255,255,255,.2); color: #eafff8; font-size: 13px; font-weight: 800; }
.badge.locked { color: #fff4bd; font-size: 17px; line-height: 1; }
.course-card.locked { filter: saturate(.95); }
.course-card > div:first-child { margin: 0; padding: 0; background: transparent; backdrop-filter: none; }
.course-card h3 { margin: 18px 0 10px; font-size: 22px; line-height: 1.28; text-shadow: 0 2px 10px rgba(0,0,0,.24); }
.course-card p { color: rgba(255,255,255,.9); text-shadow: 0 1px 8px rgba(0,0,0,.18); }
.course-card button { align-self: flex-end; }

.modal { width: min(560px, calc(100vw - 28px)); border: 0; border-radius: 10px; padding: 0; box-shadow: 0 28px 90px rgba(8,20,34,.28); }
.modal::backdrop { background: rgba(9,21,36,.64); }
.register-form, .unlock-panel { padding: 32px; position: relative; background: #fff; }
.close-button { position: absolute; top: 14px; right: 16px; border: 0; background: transparent; font-size: 28px; cursor: pointer; }
.auth-tabs { display: inline-grid; grid-template-columns: repeat(2, 1fr); gap: 4px; padding: 4px; margin-bottom: 22px; border-radius: 8px; background: #eef4f8; }
.auth-tab { min-height: 36px; border: 0; border-radius: 6px; padding: 0 14px; color: var(--muted); background: transparent; cursor: pointer; }
.auth-tab.active { color: #fff; background: var(--accent); }
.form-grid { display: grid; grid-template-columns: repeat(2, minmax(0,1fr)); gap: 14px; }
.form-grid.single { grid-template-columns: 1fr; }
label { display: grid; gap: 7px; color: var(--muted); font-size: 14px; }
label.wide { grid-column: 1 / -1; }
input { width: 100%; height: 44px; border: 1px solid var(--line); border-radius: 8px; padding: 0 12px; color: var(--ink); background: #f9fbfd; }

.admin-page { min-height: 100vh; display: grid; grid-template-columns: 260px 1fr; background: #f3f6f8; }
.admin-side { padding: 28px; background: #102033; color: #fff; }
.admin-side { position: sticky; top: 0; height: 100vh; }
.admin-side nav { display: grid; gap: 12px; margin-top: 42px; color: rgba(255,255,255,.78); }
.admin-main { padding: 38px; }
.admin-login, .admin-workspace section, .metric-row div { background: #fff; border: 1px solid var(--line); border-radius: 8px; }
.admin-login { max-width: 430px; padding: 32px; }
.admin-login form { display: grid; gap: 14px; }
.admin-form { display: grid; grid-template-columns: 140px 1fr; gap: 14px; margin-bottom: 22px; }
.admin-form .wide { grid-column: 1 / -1; }
.admin-form button { justify-self: start; }
.admin-head { display: flex; justify-content: space-between; align-items: center; margin-bottom: 22px; }
.metric-row { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; margin-bottom: 22px; }
.metric-row div { padding: 24px; }
.metric-row span { font-size: 34px; font-weight: 900; color: var(--accent-dark); }
.admin-workspace section { padding: 24px; margin-bottom: 18px; }
.table-wrap { overflow: auto; }
table { width: 100%; border-collapse: collapse; min-width: 720px; }
th, td { padding: 12px; border-bottom: 1px solid var(--line); text-align: left; white-space: nowrap; }
th { color: var(--muted); font-weight: 700; background: #f8fbfd; }
.student-notes { min-width: 260px; max-width: 420px; white-space: normal; line-height: 1.6; color: var(--ink); }
.table-actions { display: inline-flex; gap: 8px; align-items: center; }
.table-button { min-height: 32px; padding: 0 12px; border: 1px solid var(--line); border-radius: 6px; background: #fff; color: var(--accent-dark); cursor: pointer; }
.table-link { color: var(--accent-dark); border-bottom: 1px solid currentColor; }
.course-thumb { width: 82px; height: 46px; object-fit: cover; border-radius: 6px; display: block; }
code { background: #eef4f8; padding: 2px 5px; border-radius: 4px; }
.site-footer { display: flex; gap: 22px; flex-wrap: wrap; justify-content: flex-end; text-align: right; padding: 28px 5vw; background: #0d1a29; color: rgba(255,255,255,.78); }
.site-footer p { margin: 0; }

@keyframes rise { from { opacity: 0; transform: translateY(18px); } to { opacity: 1; transform: translateY(0); } }

@media (max-width: 900px) {
  .site-header { position: sticky; color: var(--white); background: #102033; border-bottom: 1px solid rgba(255,255,255,.12); }
  .brand-logos { min-width: 0; }
  .brand-logos img:first-child { width: 150px; }
  .brand-logos img:last-child { width: 76px; }
  .top-nav { display: none; }
  .hero { min-height: 410px; padding-top: 86px; }
  .hero-shade { background: rgba(9,21,36,.72); }
  .steps, .pricing-band, .pricing-options, .course-grid, .course-grid.five, .admin-page, .metric-row { grid-template-columns: 1fr; }
  .course-grid { gap: 14px; }
  .admin-side { position: static; height: auto; }
  .form-grid, .admin-form { grid-template-columns: 1fr; }
  .site-footer { justify-content: flex-start; text-align: left; }
}