:root {
    --primary: #5C6BC0; --bg: #f6f7fc; --card-bg: #fff;
    --text: #333; --text-light: #888; --shadow: 0 2px 10px rgba(0,0,0,.06);
}
* { box-sizing: border-box; }
body { margin: 0; font-family: -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif; background: var(--bg); color: var(--text); }
.navbar { display: flex; justify-content: space-between; align-items: center; padding: 14px 20px; background: #fff; box-shadow: var(--shadow); position: sticky; top: 0; z-index: 500; }
.navbar .logo { font-weight: bold; font-size: 18px; }
.nav-links { display: flex; gap: 14px; }
.nav-links a { color: var(--text); text-decoration: none; font-size: 14px; }
.container { max-width: 760px; margin: 0 auto; padding: 18px 14px 40px; }
.hero { background: linear-gradient(135deg, #e8eaf6, #f3e5f5); border-radius: 16px; padding: 22px 18px; margin-bottom: 16px; }
.hero h1 { margin: 0 0 6px; font-size: 24px; }
.hero p { margin: 0; color: #555; font-size: 14px; }
.subject-grid { display: grid; gap: 12px; }
.subject-card { background: var(--card-bg); border-radius: 16px; padding: 18px 14px; box-shadow: var(--shadow); text-align: center; display: block; }
.subject-card .icon { font-size: 34px; }
.subject-card .name { font-weight: bold; margin: 6px 0 4px; font-size: 16px; }
.subject-card .desc { font-size: 12.5px; color: var(--text-light); margin: 2px 0; }
.account-box { background: var(--card-bg); border-radius: 14px; padding: 14px 16px; box-shadow: var(--shadow); display: flex; flex-direction: column; gap: 6px; font-size: 14px; }
.account-tip { color: var(--text-light); font-size: 12.5px; line-height: 1.6; }
.res-row { padding: 8px 0; border-bottom: 1px dashed #eee; }
.res-row:last-child { border-bottom: none; }
.res-badge { display: inline-block; font-size: 11.5px; border-radius: 6px; padding: 2px 8px; margin-right: 8px; background: #e8eaf6; color: #3949ab; }
.res-video { background: #fce4ec; color: #c2185b; }
.res-book { background: #e8f5e9; color: #2e7d32; }
.res-link { color: var(--primary); text-decoration: none; font-size: 14px; font-weight: bold; word-break: break-all; }
.res-link:hover { text-decoration: underline; }
.res-note { color: var(--text-light); font-size: 12.5px; margin-top: 3px; }
input.ms-chk { width: 17px; height: 17px; accent-color: var(--primary); margin-top: 2px; }
.btn { display: inline-block; border: none; border-radius: 10px; padding: 10px 18px; font-size: 14px; cursor: pointer; text-decoration: none; }
.btn-primary { background: var(--primary); color: #fff; }
.btn-ghost { background: #fff; color: var(--text); border: 1.5px solid #ddd; }
.article-body { background: var(--card-bg); border-radius: 16px; padding: 22px 20px; box-shadow: var(--shadow); font-size: 14.5px; line-height: 1.85; }
.article-body h1 { font-size: 21px; margin: 0 0 10px; }
.article-body h2 { font-size: 17.5px; margin: 26px 0 8px; border-left: 4px solid var(--primary); padding-left: 10px; }
.article-body h3 { font-size: 15.5px; margin: 18px 0 6px; }
.article-body p { margin: 8px 0; }
.article-body table { border-collapse: collapse; width: 100%; margin: 10px 0; font-size: 13px; display: block; overflow-x: auto; }
.article-body th, .article-body td { border: 1px solid #e3e5f0; padding: 7px 9px; text-align: left; vertical-align: top; }
.article-body th { background: #f0f1fa; }
.article-body ul, .article-body ol { padding-left: 22px; margin: 8px 0; }
.article-body li { margin: 4px 0; }
.article-body hr { border: none; border-top: 1px solid #eee; margin: 18px 0; }
.article-body a { color: var(--primary); }
.article-body .meta { color: var(--text-light); font-size: 12.5px; }
@media (max-width: 640px) {
    .subject-grid { grid-template-columns: 1fr !important; }
    .navbar { flex-wrap: wrap; }
}