/* coursegen-fixed-chapter-shell-v1 */
:root {
    color-scheme: light;
    --page-bg: #fffaf2;
    --panel-bg: #ffffff;
    --panel-soft: #ccfbf1;
    --line: #b8d8ff;
    --line-strong: #4f9df7;
    --primary: #0f766e;
    --accent: #ea580c;
    --text: #1f2937;
    --muted: #526173;
    --shadow: 0 18px 48px rgba(37, 99, 235, 0.14);
}
* {
    box-sizing: border-box;
}
html {
    background: var(--page-bg);
}
body {
    margin: 0;
    color: var(--text);
    font-family: "Microsoft YaHei", "PingFang SC", Arial, sans-serif;
    line-height: 1.78;
    background:
        linear-gradient(135deg, rgba(79, 157, 247, 0.14), rgba(245, 158, 11, 0.10)),
        var(--page-bg);
}
a {
    color: inherit;
}
.course-page {
    width: min(1440px, calc(100% - 32px));
    margin: 0 auto;
    padding: 28px 0 36px;
}
.course-shell {
    display: grid;
    grid-template-columns: minmax(220px, 272px) minmax(0, 1fr);
    align-items: start;
    gap: 24px;
}
.course-sidebar,
.course-main {
    background: rgba(255, 255, 255, 0.94);
    border: 2px solid var(--line-strong);
    outline: 4px solid rgba(184, 216, 255, 0.58);
    border-radius: 8px;
    box-shadow: var(--shadow);
}
.course-sidebar {
    padding: 18px 14px;
}
.course-sidebar-title {
    margin: 0 0 14px;
    padding: 0 4px 12px;
    border-bottom: 1px solid var(--line);
    color: var(--primary);
    font-size: 18px;
    font-weight: 800;
    text-align: center;
}
.course-nav-list {
    display: grid;
    gap: 8px;
}
.course-nav-link {
    display: grid;
    grid-template-columns: 62px minmax(0, 1fr);
    gap: 8px;
    align-items: center;
    min-width: 0;
    padding: 9px 10px;
    border: 1px solid #d6e8ff;
    border-radius: 8px;
    background: #f7fbff;
    color: var(--text);
    text-decoration: none;
}
.course-nav-link:hover,
.course-nav-link.is-active {
    border-color: var(--primary);
    background: #edf6ff;
}
.course-nav-index {
    color: var(--primary);
    font-size: 13px;
    font-weight: 800;
    white-space: nowrap;
}
.course-nav-name {
    min-width: 0;
    color: var(--muted);
    font-size: 13px;
    line-height: 1.42;
    overflow-wrap: anywhere;
}
.course-main {
    min-width: 0;
    padding: clamp(22px, 3vw, 42px);
}
.course-title-top {
    margin: 0 auto 18px;
    color: var(--primary);
    font-size: clamp(24px, 3vw, 36px);
    font-weight: 900;
    line-height: 1.28;
    text-align: center;
    overflow-wrap: anywhere;
}
.chapter-content {
    min-width: 0;
}
.chapter-content h2 {
    margin: 12px 0 18px;
    color: var(--text);
    font-size: clamp(24px, 2.4vw, 32px);
    line-height: 1.35;
    text-align: center;
}
.chapter-content h3 {
    margin: 28px 0 12px;
    padding-left: 12px;
    border-left: 5px solid var(--accent);
    color: var(--primary);
    font-size: 22px;
    line-height: 1.35;
}
.chapter-content p {
    margin: 12px 0;
}
.chapter-content ul,
.chapter-content ol {
    margin: 12px 0 16px;
    padding-left: 1.5em;
}
.chapter-content li {
    margin: 6px 0;
}
.chapter-content table {
    width: 100%;
    margin: 18px 0;
    border-collapse: collapse;
    background: #ffffff;
}
.chapter-content th,
.chapter-content td {
    padding: 10px 12px;
    border: 1px solid #c8ddfb;
    vertical-align: top;
}
.chapter-content th {
    background: var(--panel-soft);
    color: var(--primary);
}
.chapter-content pre {
    margin: 18px 0;
    padding: 16px;
    border: 1px solid #c8ddfb;
    border-radius: 8px;
    background: #102033;
    color: #eef7ff;
    overflow-x: auto;
}
.chapter-content code {
    font-family: Consolas, "Courier New", monospace;
    font-size: 0.95em;
}
.chapter-content svg {
    display: block;
    max-width: 100%;
    height: auto;
    margin: 18px auto;
}
.highlight,
.tip,
.warning {
    margin: 18px 0;
    padding: 14px 16px;
    border: 1px solid #c8ddfb;
    border-left-width: 6px;
    border-radius: 8px;
    background: #f7fbff;
}
.highlight {
    border-left-color: var(--primary);
}
.tip {
    border-left-color: #10b981;
    background: #f1fff8;
}
.warning {
    border-left-color: var(--accent);
    background: #fff8eb;
}
.chapter-actions {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 12px;
    margin-top: 34px;
    padding-top: 22px;
    border-top: 1px solid var(--line);
}
.chapter-action {
    min-width: 116px;
    padding: 9px 14px;
    border: 1px solid var(--primary);
    border-radius: 8px;
    background: #ffffff;
    color: var(--primary);
    text-align: center;
    text-decoration: none;
    font-weight: 800;
}
.chapter-action.is-disabled {
    border-color: #cbd5e1;
    color: #94a3b8;
    pointer-events: none;
}
.course-footer {
    margin: 24px auto 0;
    padding: 16px;
    border: 2px solid var(--line-strong);
    outline: 4px solid rgba(184, 216, 255, 0.58);
    border-radius: 8px;
    background: rgba(255, 255, 255, 0.94);
    color: var(--muted);
    text-align: center;
    font-size: 14px;
}
@media (max-width: 860px) {
    .course-page {
        width: min(100% - 18px, 720px);
        padding-top: 14px;
    }
    .course-shell {
        grid-template-columns: 1fr;
        gap: 16px;
    }
    .course-nav-link {
        grid-template-columns: 58px minmax(0, 1fr);
    }
    .course-main {
        padding: 18px 14px;
    }
}