:root {
    --ink: #183145;
    --muted: #637483;
    --surface: #ffffff;
    --canvas: #f3f7f8;
    --brand: #147b8f;
    --brand-dark: #0d5f71;
    --line: #dce6e8;
}
body.home-page { background: var(--canvas); color: var(--ink); font-family: "Microsoft YaHei", "PingFang SC", Arial, sans-serif; padding: 0; }
.home-nav { background: var(--surface); border-bottom: 1px solid var(--line); min-height: 68px; }
.home-shell { width: min(1120px, calc(100% - 32px)); margin: 0 auto; }
.home-nav .home-shell { align-items: center; display: flex; justify-content: space-between; min-height: 68px; }
.brand { color: var(--ink); font-size: 21px; font-weight: 700; text-decoration: none; }
.brand-mark { background: var(--brand); border-radius: 4px; color: #fff; display: inline-block; font-size: 15px; line-height: 29px; margin-right: 8px; text-align: center; width: 29px; }
.nav-links { align-items: center; display: flex; gap: 8px; }
.nav-links a { border-radius: 4px; color: var(--muted); padding: 8px 11px; text-decoration: none; }
.nav-links a:hover { background: #e8f2f3; color: var(--brand-dark); }
.nav-links .login-link { background: var(--brand); color: #fff; }
.nav-links .login-link:hover { background: var(--brand-dark); color: #fff; }
.home-main { padding: 54px 0 42px; }
.intro { max-width: 670px; text-align: center; margin: 0 auto 42px; }
.intro h1 { font-size: 34px; font-weight: 700; line-height: 1.3; margin: 0 0 14px; }
.intro p { color: var(--muted); font-size: 16px; line-height: 1.8; margin: 0; }
.course-grid { display: grid; gap: 20px; grid-template-columns: repeat(4, minmax(0, 1fr)); }
.course-card { background: var(--surface); border: 1px solid var(--line); border-radius: 6px; color: var(--ink); display: flex; flex-direction: column; min-width: 0; overflow: hidden; text-decoration: none; transition: box-shadow .2s ease, transform .2s ease; }
.course-card:hover { box-shadow: 0 10px 24px rgba(20, 67, 84, .13); transform: translateY(-3px); }
.course-card img { aspect-ratio: 4 / 3; background: #dfecee; display: block; object-fit: cover; width: 100%; }
.course-card-content { display: flex; flex: 1; flex-direction: column; padding: 18px; }
.course-card h2 { font-size: 18px; line-height: 1.45; margin: 0 0 8px; }
.course-card p { color: var(--muted); flex: 1; font-size: 14px; line-height: 1.65; margin: 0 0 18px; }
.course-card-action { border: 1px solid var(--brand); border-radius: 4px; color: var(--brand-dark); display: block; padding: 8px 10px; text-align: center; }
.course-card:hover .course-card-action { background: var(--brand); color: #fff; }
.latest { margin-top: 54px; }
.section-heading { align-items: baseline; display: flex; justify-content: space-between; margin-bottom: 14px; }
.section-heading h2 { font-size: 21px; margin: 0; }
.section-heading a { color: var(--brand-dark); text-decoration: none; }
.latest-list { background: var(--surface); border: 1px solid var(--line); border-radius: 6px; margin: 0; padding: 0; }
.latest-list li { border-bottom: 1px solid var(--line); list-style: none; padding: 14px 18px; }
.latest-list li:last-child { border-bottom: 0; }
.latest-list a { color: var(--brand-dark); text-decoration: none; }
.empty-state { color: var(--muted); }
.home-footer { border-top: 1px solid var(--line); color: var(--muted); font-size: 13px; padding: 22px 0; text-align: center; }
@media (max-width: 900px) { .course-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); } }
@media (max-width: 560px) { .home-nav .home-shell { align-items: flex-start; flex-direction: column; padding: 14px 0; } .nav-links { flex-wrap: wrap; } .home-main { padding-top: 36px; } .intro h1 { font-size: 28px; } .course-grid { grid-template-columns: 1fr; } }