:root {
  --ink: #18364b;
  --muted: #5c7281;
  --paper: #f7fbfd;
  --white: #fff;
  --blue: #2f9bd4;
  --cobalt: #285b9c;
  --green: #79c94a;
  --green-dark: #347a4b;
  --yellow: #ffd43b;
  --coral: #e64f42;
  --line: #d6e3ea;
  --nav-height: 76px;
  font-family: "Source Han Sans SC", "Microsoft YaHei UI", "PingFang SC", "Noto Sans CJK SC", sans-serif;
  color: var(--ink);
  background: var(--paper);
  font-synthesis: none;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: calc(var(--nav-height) + 18px); }
body { margin: 0; min-width: 320px; background: var(--paper); }
button, input { font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
a { color: inherit; text-decoration: none; }
button { color: inherit; }
[hidden] { display: none !important; }

.site-nav {
  position: sticky;
  inset: 0 0 auto;
  z-index: 50;
  min-height: var(--nav-height);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 26px;
  padding: 10px clamp(18px, 5vw, 72px);
  border-bottom: 1px solid rgba(40, 91, 156, .13);
  background: rgba(255, 255, 255, .96);
  backdrop-filter: blur(12px);
}
.brand { display: inline-flex; align-items: center; gap: 12px; min-width: 220px; }
.brand-logo { display: block; width: 64px; height: 56px; flex: none; object-fit: contain; }
.brand-copy { display: grid; gap: 3px; }
.brand-copy strong { font-size: 18px; font-weight: 800; }
.brand-copy small { color: var(--muted); font-size: 11px; }
.nav-links { display: flex; align-items: center; justify-content: center; gap: clamp(18px, 3vw, 42px); margin-left: auto; }
.nav-links a { padding: 10px 0; color: #355a71; font-size: 14px; font-weight: 650; }
.nav-links a:hover { color: var(--cobalt); }
.menu-toggle { display: none; min-height: 38px; padding: 0 10px; border: 1px solid #b8d6e5; color: var(--cobalt); background: #fff; font-size: 12px; font-weight: 700; cursor: pointer; }
.nav-actions { display: flex; align-items: center; gap: 8px; }
.nav-button, .account-trigger {
  min-height: 40px;
  padding: 0 15px;
  border: 1px solid #b8d6e5;
  background: var(--white);
  color: var(--cobalt);
  cursor: pointer;
  transition: background .18s ease, border-color .18s ease, translate .18s ease;
}
.nav-button:hover, .account-trigger:hover { border-color: var(--blue); background: #eef8fd; }
.nav-points { display: inline-flex; align-items: center; gap: 9px; border-color: #e5c336; color: #594c12; background: #fff7cf; }
.nav-points:hover { border-color: #d3ac0b; background: #fff0a6; }
.point-dot { width: 9px; height: 9px; flex: none; border-radius: 50%; background: var(--yellow); box-shadow: 0 0 0 3px rgba(211, 172, 11, .16); }
.account-menu { position: relative; }
.account-trigger { display: flex; align-items: center; gap: 8px; }
.account-popover { position: absolute; right: 0; top: calc(100% + 9px); min-width: 150px; display: none; padding: 7px; border: 1px solid var(--line); background: var(--white); box-shadow: 0 16px 32px rgba(24, 54, 75, .15); }
.account-menu.open .account-popover { display: block; }
.account-popover button { display: block; width: 100%; padding: 11px; border: 0; text-align: left; background: none; cursor: pointer; }
.account-popover button:hover { background: #eef8fd; }

.hero { position: relative; min-height: min(790px, calc(100svh - var(--nav-height))); overflow: hidden; background: #eaf7fd url('/assets/gaoge-study-hero-4k.png') center/cover no-repeat; }
.hero::before { position: absolute; inset: 0; content: ''; background: linear-gradient(90deg, rgba(255,255,255,.97) 0%, rgba(255,255,255,.93) 39%, rgba(255,255,255,.66) 66%, rgba(255,255,255,.26) 100%); }
.hero-wash { position: absolute; inset: 0; background: linear-gradient(0deg, rgba(255,255,255,.42), transparent 28%); }
.hero-inner { position: relative; z-index: 1; width: min(1480px, 100%); min-height: min(790px, calc(100svh - var(--nav-height))); margin: 0 auto; padding: 74px clamp(24px, 6vw, 90px) 100px; display: flex; align-items: center; }
.hero-copy { max-width: 780px; }
.hero h1 { max-width: 790px; margin: 0; color: var(--ink); font-size: 54px; line-height: 1.2; font-weight: 750; }
.hero h1 strong { color: var(--cobalt); font-weight: 850; }
.hero h1 span { display: block; }
.hero-services { display: grid; gap: 10px; max-width: 680px; margin: 27px 0 0; padding: 0; list-style: none; }
.hero-services li { position: relative; padding-left: 21px; color: #35576d; font-size: 16px; line-height: 1.65; }
.hero-services li::before { position: absolute; left: 0; top: .53em; width: 9px; height: 9px; border-radius: 2px 7px 2px 7px; background: var(--green); content: ''; rotate: 45deg; }
.hero-services li:nth-child(2)::before { background: var(--blue); }
.hero-services li:nth-child(3)::before { background: var(--yellow); }
.hero-actions { display: flex; flex-wrap: wrap; align-items: center; gap: 20px; margin-top: 32px; }
.primary-action { display: inline-flex; align-items: center; justify-content: space-between; gap: 26px; min-height: 50px; padding: 0 18px; border: 1px solid var(--cobalt); color: var(--white); background: var(--cobalt); font-weight: 750; transition: translate .18s ease, background .18s ease; }
.primary-action:hover { translate: 0 -2px; background: #1c477f; }
.primary-action span { font-size: 20px; }

.workbench { padding: 92px clamp(18px, 5vw, 78px) 118px; background: var(--paper); }
.workbench-heading { width: min(1480px, 100%); margin: 0 auto 58px; }
.workbench-heading h2 { max-width: 1120px; margin: 0; font-size: 40px; line-height: 1.3; font-weight: 760; }
.workbench-heading h2 span { display: block; }
.workbench-heading h2 span + span { color: var(--green-dark); }
.module-groups { width: min(1480px, 100%); margin: 0 auto; }
.module-group + .module-group { margin-top: 77px; }
.module-group-heading { display: flex; align-items: end; justify-content: space-between; gap: 28px; margin-bottom: 22px; padding: 0 0 16px 18px; border-bottom: 1px solid var(--line); border-left: 5px solid var(--group-accent, var(--blue)); }
.module-group--learning-diagnosis { --group-accent: var(--blue); }
.module-group--self-study { --group-accent: var(--green); }
.module-group--self-testing { --group-accent: var(--coral); }
.module-group--self-practice { --group-accent: #d0a800; }
.module-group-kicker { margin: 0 0 8px; color: var(--group-accent, var(--blue)); font: 700 10px/1.3 Arial, sans-serif; letter-spacing: .16em; }
.module-group-heading h2 { margin: 0; font-size: 29px; line-height: 1.3; font-weight: 760; }
.module-group-heading > p { max-width: 460px; margin: 0 0 2px; color: var(--muted); font-size: 13px; line-height: 1.7; }
.module-grid { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); border-top: 1px solid var(--line); border-left: 1px solid var(--line); }
.module-card { position: relative; min-width: 0; min-height: 246px; display: flex; flex-direction: column; padding: 20px 19px 18px; border-right: 1px solid var(--line); border-bottom: 1px solid var(--line); background: #fff; overflow: hidden; transition: background .18s ease, box-shadow .18s ease, translate .18s ease; }
.module-card:hover { z-index: 1; translate: 0 -2px; background: #fbfeff; box-shadow: 0 9px 20px rgba(36, 91, 137, .11); }
.module-card::after { position: absolute; inset: auto 0 0; height: 3px; background: var(--group-accent, var(--blue)); content: ''; scale: 0 1; transform-origin: left; transition: scale .2s ease; }
.module-card:hover::after { scale: 1 1; }
.module-top { display: flex; justify-content: space-between; align-items: center; gap: 12px; }
.module-number { color: var(--group-accent, var(--blue)); font: 700 11px/1.2 Arial, sans-serif; letter-spacing: .08em; }
.module-cost { padding: 4px 0 4px 8px; border-left: 2px solid var(--yellow); color: #73818a; font-size: 10px; white-space: nowrap; }
.module-title { margin: 22px 0 8px; font-size: 20px; line-height: 1.35; font-weight: 760; overflow-wrap: anywhere; }
.module-label { margin: 0 0 6px; color: var(--cobalt); font-size: 13px; font-weight: 700; line-height: 1.5; }
.module-description { margin: 0; min-height: 44px; color: var(--muted); font-size: 12px; line-height: 1.7; }
.module-enter { margin-top: auto; padding-top: 15px; display: flex; align-items: center; justify-content: space-between; color: var(--green-dark); font-size: 12px; font-weight: 750; }
.module-enter b { color: var(--cobalt); font-size: 20px; font-weight: 500; transition: translate .18s ease; }
.module-card:hover .module-enter b { translate: 3px -2px; }
.module-card[aria-disabled="true"] { color: #8a969c; background: #f1f4f6; cursor: not-allowed; }
.module-card[aria-disabled="true"] .module-title, .module-card[aria-disabled="true"] .module-label, .module-card[aria-disabled="true"] .module-description { color: #89969b; }
.module-loading { padding: 28px; color: var(--muted); }

footer { color: #fff; background: #1a4054; }
.footer-main { width: min(1480px, 100%); margin: 0 auto; padding: 56px clamp(18px, 5vw, 78px) 44px; display: grid; grid-template-columns: minmax(0, 1.4fr) minmax(210px, .6fr); gap: 38px; }
.footer-brand { display: flex; align-items: center; gap: 11px; }
.footer-brand-logo { display: block; width: 66px; height: 58px; flex: none; object-fit: contain; }
.footer-brand strong { display: block; font-size: 18px; }
.footer-brand small { display: block; margin-top: 3px; color: #bbd2dc; font-size: 11px; }
.footer-brand-block > p { max-width: 560px; margin: 20px 0 0; color: #d6e5eb; font-size: 13px; line-height: 1.8; }
.footer-contact { display: flex; flex-wrap: wrap; align-items: baseline; gap: 10px 24px; margin-top: 10px; }
.footer-contact div { display: flex; flex-wrap: wrap; gap: 6px; align-items: baseline; }
.footer-contact span { color: #b6d4e1; font-size: 12px; }
.footer-contact strong { color: #fff; font: 700 15px/1.3 Arial, sans-serif; }
.footer-links { align-self: start; display: grid; }
.footer-links a, .footer-links button { min-height: 45px; display: grid; grid-template-columns: 1fr 18px; align-items: center; gap: 12px; padding: 0; border: 0; border-bottom: 1px solid rgba(255,255,255,.2); color: #fff; background: transparent; text-align: left; cursor: pointer; }
.footer-links a:hover, .footer-links button:hover { color: var(--yellow); }
.footer-links b { font-size: 16px; font-weight: 500; }
.footer-bottom { min-height: 48px; padding: 12px clamp(18px, 5vw, 78px); display: flex; justify-content: space-between; gap: 15px; color: #b6ced8; background: #143648; font-size: 10px; }

.modal { position: fixed; width: min(480px, calc(100vw - 30px)); max-height: min(88vh, 740px); padding: 36px; border: 1px solid #d7e4ea; color: var(--ink); background: var(--paper); box-shadow: 0 28px 70px rgba(14, 44, 64, .28); }
.modal::backdrop { background: rgba(13, 44, 63, .58); backdrop-filter: blur(5px); }
.modal-close { position: absolute; right: 14px; top: 12px; width: 36px; height: 36px; border: 0; color: var(--muted); background: none; font-size: 25px; cursor: pointer; }
.modal-heading p { margin: 0 0 10px; color: var(--cobalt); font-size: 12px; font-weight: 750; }
.modal-heading h2 { margin: 0 0 9px; font-size: 28px; line-height: 1.3; }
.modal-heading span { color: var(--muted); font-size: 13px; line-height: 1.7; }
.auth-tabs { display: grid; grid-template-columns: 1fr 1fr; margin: 27px 0 21px; border-bottom: 1px solid var(--line); }
.auth-tabs button { min-height: 43px; border: 0; border-bottom: 3px solid transparent; color: var(--muted); background: none; cursor: pointer; }
.auth-tabs button.active { border-bottom-color: var(--green); color: var(--ink); font-weight: 750; }
.auth-form, .points-form { display: grid; gap: 15px; }
.auth-form label, .points-form label { display: grid; gap: 7px; font-size: 12px; font-weight: 700; }
.auth-form input, .points-form input { width: 100%; min-height: 46px; padding: 0 12px; border: 1px solid #b8cbd5; background: #fff; outline: 0; }
.auth-form input:focus, .points-form input:focus { border-color: var(--blue); box-shadow: 0 0 0 3px rgba(47, 155, 212, .14); }
.agreement-consent { display: flex; align-items: center; flex-wrap: wrap; gap: 6px; color: var(--muted); font-size: 12px; line-height: 1.6; }
.agreement-check { display: inline-flex !important; align-items: center; gap: 7px !important; font-weight: 400 !important; cursor: pointer; }
.agreement-check input { width: 16px; min-height: 16px; flex: none; accent-color: var(--green-dark); cursor: pointer; }
.agreement-consent a { color: var(--cobalt); text-decoration: underline; text-underline-offset: 3px; }
.modal-primary { min-height: 46px; border: 0; color: #fff; background: var(--cobalt); font-weight: 750; cursor: pointer; }
.modal-primary:hover { background: #1c477f; }
.form-message { min-height: 20px; margin: 0; color: var(--coral); font-size: 12px; }
.form-message.success { color: var(--green-dark); }
.purchase-divider { display: flex; align-items: center; gap: 12px; margin: 23px 0 12px; color: #758791; font-size: 11px; }
.purchase-divider::before, .purchase-divider::after { height: 1px; flex: 1; background: var(--line); content: ''; }
.purchase-link { display: flex; align-items: center; justify-content: space-between; padding: 13px 2px; border-bottom: 1px solid var(--cobalt); color: var(--cobalt); font-weight: 750; }
.purchase-link:hover { color: var(--coral); border-color: var(--coral); }
:focus-visible { outline: 3px solid var(--coral); outline-offset: 3px; }

@media (min-width: 1600px) {
  .hero h1 { font-size: 58px; }
}
@media (max-width: 1180px) {
  .nav-links { gap: 18px; }
  .hero-copy { max-width: 720px; }
  .hero h1 { font-size: 48px; }
  .module-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
}
@media (max-width: 900px) {
  :root { --nav-height: 68px; }
  .site-nav { gap: 12px; padding-right: 16px; padding-left: 16px; }
  .brand { min-width: 0; }
  .menu-toggle { display: inline-flex; align-items: center; justify-content: center; }
  .nav-links { display: none; }
  .site-nav.nav-open .nav-links { position: absolute; top: 100%; left: 0; right: 0; display: grid; gap: 0; margin: 0; padding: 8px 18px 13px; border-bottom: 1px solid var(--line); background: #fff; box-shadow: 0 12px 18px rgba(24, 54, 75, .1); }
  .site-nav.nav-open .nav-links a { padding: 12px 2px; border-bottom: 1px solid #e7eef2; }
  .nav-actions { margin-left: auto; }
  .hero { min-height: 680px; background-position: 61% center; }
  .hero-inner { min-height: 680px; padding: 74px 34px 80px; }
  .hero::before { background: linear-gradient(90deg, rgba(255,255,255,.97) 0%, rgba(255,255,255,.91) 52%, rgba(255,255,255,.56) 100%); }
  .hero h1 { font-size: 42px; }
  .hero-services li { font-size: 14px; }
  .workbench-heading { margin-bottom: 45px; }
  .workbench-heading h2 { font-size: 33px; }
  .module-group-heading { align-items: start; flex-direction: column; gap: 10px; }
  .module-group-heading > p { max-width: 620px; }
  .footer-main { grid-template-columns: minmax(0, 1.25fr) minmax(140px, .75fr); gap: 30px; }
  .footer-links { grid-column: 1 / -1; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 24px; }
}
@media (max-width: 660px) {
  :root { --nav-height: 64px; }
  .site-nav { min-height: var(--nav-height); padding: 8px 12px; }
  .brand { gap: 8px; }
  .brand-logo { width: 52px; height: 44px; }
  .brand-copy strong { font-size: 14px; }
  .brand-copy small { font-size: 9px; }
  .menu-toggle { min-height: 36px; padding: 0 8px; }
  .nav-button { min-height: 36px; padding: 0 9px; font-size: 11px; }
  .nav-auth { display: none; }
  .account-name { max-width: 76px; overflow: hidden; text-overflow: ellipsis; }
  .hero { min-height: 660px; background-position: 67% top; }
  .hero::before { background: linear-gradient(180deg, rgba(255,255,255,.78) 0%, rgba(255,255,255,.94) 28%, rgba(255,255,255,.97) 100%); }
  .hero-inner { min-height: 660px; padding: 74px 20px 64px; }
  .hero-copy { max-width: none; }
  .hero h1 { font-size: 30px; line-height: 1.28; }
  .hero-services { gap: 8px; margin-top: 20px; }
  .hero-services li { padding-left: 17px; font-size: 13px; line-height: 1.55; }
  .hero-services li::before { width: 7px; height: 7px; }
  .hero-actions { align-items: flex-start; flex-direction: column; gap: 11px; margin-top: 23px; }
  .primary-action { min-height: 46px; gap: 14px; padding: 0 13px; font-size: 13px; }
  .workbench { padding: 62px 14px 80px; }
  .workbench-heading { margin-bottom: 36px; }
  .workbench-heading h2 { font-size: 25px; }
  .module-group + .module-group { margin-top: 54px; }
  .module-group-heading { padding-left: 13px; }
  .module-group-heading h2 { font-size: 24px; }
  .module-grid { grid-template-columns: 1fr; }
  .module-card { min-height: 218px; padding: 17px; }
  .module-title { margin-top: 17px; font-size: 19px; }
  .footer-main { grid-template-columns: 1fr; gap: 28px; padding: 38px 20px 32px; }
  .footer-links { grid-column: auto; grid-template-columns: 1fr; gap: 0; }
  .footer-bottom { flex-wrap: wrap; padding: 12px 20px; }
  .footer-bottom span:nth-child(2) { display: none; }
  .modal { padding: 32px 22px 23px; }
}
@media (max-width: 430px) {
  .site-nav { gap: 6px; padding-right: 8px; padding-left: 8px; }
  .brand { flex: none; gap: 6px; }
  .brand-logo { width: 42px; height: 38px; }
  .brand-copy strong { font-size: 12px; white-space: nowrap; }
  .brand-copy small { font-size: 8px; white-space: nowrap; }
  .menu-toggle { min-height: 34px; padding: 0 5px; font-size: 10px; white-space: nowrap; }
  .nav-actions { flex: none; gap: 4px; }
  .nav-points { gap: 5px; padding-right: 6px; padding-left: 6px; font-size: 10px; white-space: nowrap; }
  .account-trigger { gap: 5px; padding-right: 6px; padding-left: 6px; font-size: 10px; }
  .account-name { max-width: 66px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; }
}