/* ============================================================
   水族历史 · 主界面样式（导航栏式：起源 / 古代·迁徙史 / 近现代·抗争史）
   配色遵循组内统一规范：主色 #24406C / 辅金 #C9A227 / 米白 #F7F2E7
   ============================================================ */
:root {
    --indigo: #24406C;
    --indigo-dark: #1A3054;
    --indigo-light: #3B5C8F;
    --gold: #C9A227;
    --gold-light: #E5C76B;
    --cream: #F7F2E7;
    --card: #FFFDF6;
    --text: #333A45;
    --text-soft: #5A6474;
    --font-display: "华文行楷", "STXingkai", "LXGW WenKai", "华文楷体", "STKaiti", "KaiTi", "Microsoft YaHei", serif;
    --font-kai: "LXGW WenKai", "华文楷体", "STKaiti", "KaiTi", "Microsoft YaHei", serif;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
    font-family: var(--font-kai);
    background: var(--cream);
    color: var(--text);
    min-height: 100vh;
}

/* ============ 顶部导航栏 ============ */
.top-nav {
    position: fixed;
    top: 0; left: 0; right: 0;
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 10px 28px;
    background: rgba(255, 253, 246, 0.95);
    border-bottom: 2px solid rgba(201, 162, 39, 0.45);
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.12);
    backdrop-filter: blur(4px);
}
.nav-brand {
    display: flex;
    align-items: center;
    gap: 10px;
}
.brand-ornament { width: 26px; height: 26px; opacity: 0.85; }
.brand-title {
    font-family: var(--font-display);
    font-size: 24px;
    letter-spacing: 4px;
    color: var(--indigo);
}
.nav-links {
    display: flex;
    gap: 8px;
}
.nav-link {
    font-family: var(--font-kai);
    font-size: 16px;
    color: var(--text);
    background: transparent;
    border: 1px solid transparent;
    border-radius: 22px;
    padding: 7px 22px;
    cursor: pointer;
    letter-spacing: 2px;
    transition: all 0.2s ease;
}
.nav-link:hover { color: var(--indigo); border-color: rgba(36, 64, 108, 0.3); }
.nav-link.active {
    background: var(--indigo);
    border-color: var(--indigo);
    color: var(--card);
}

/* ============ 页面主体 ============ */
.page {
    max-width: 1120px;
    margin: 0 auto;
    padding: 108px 28px 60px;
}

/* 板块 */
.section { display: none; }
.section.active { display: block; animation: fadeIn 0.35s ease; }
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to   { opacity: 1; transform: none; }
}

.sec-head {
    text-align: center;
    margin-bottom: 34px;
    padding-bottom: 18px;
    border-bottom: 2px solid rgba(201, 162, 39, 0.35);
}
.sec-title {
    font-family: var(--font-display);
    font-size: 34px;
    font-weight: 400;
    letter-spacing: 6px;
    color: var(--indigo);
}
.sec-sub {
    margin-top: 8px;
    font-size: 15px;
    color: var(--text-soft);
    letter-spacing: 1px;
}

/* ============ 大词条导航栏（锚点跳转） ============ */
.sub-nav {
    display: flex;
    width: 100%;
    justify-content: center;
    flex-wrap: wrap;
    gap: 10px;
    margin: 0 auto 30px;
    max-width: 860px;
}
.sub-nav a {
    flex: 0 1 auto;
    min-width: 0;
    text-align: center;
    font-family: var(--font-kai);
    font-size: 15px;
    color: var(--indigo);
    background: var(--card);
    border: 1px solid rgba(201, 162, 39, 0.6);
    border-radius: 26px;
    padding: 10px 18px;
    text-decoration: none;
    letter-spacing: 1px;
    transition: all 0.2s ease;
    white-space: nowrap;
}
.sub-nav a:hover {
    background: rgba(201, 162, 39, 0.14);
    border-color: var(--gold);
    transform: translateY(-1px);
}

/* ============ 大词条分区标题 ============ */
.group-title {
    font-family: var(--font-display);
    font-size: 26px;
    font-weight: 400;
    color: var(--indigo);
    text-align: center;
    letter-spacing: 3px;
    margin: 44px 0 22px;
    padding-bottom: 12px;
    position: relative;
}
.group-title::after {
    content: "";
    position: absolute;
    left: 50%;
    bottom: 0;
    transform: translateX(-50%);
    width: 72px;
    height: 3px;
    background: linear-gradient(90deg, transparent, var(--gold), transparent);
    border-radius: 2px;
}
.group-title:first-child { margin-top: 0; }

/* ============ 小词条卡片（上下并列，全部展开，可点击） ============ */
.mini-card {
    display: grid;
    grid-template-columns: 300px 1fr;
    gap: 26px;
    background: var(--card);
    border: 1px solid rgba(36, 64, 108, 0.14);
    border-left: 4px solid var(--gold);
    border-radius: 14px;
    padding: 20px;
    margin-bottom: 20px;
    box-shadow: 0 3px 10px rgba(0, 0, 0, 0.05);
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
    position: relative;
}
.mini-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 18px rgba(0, 0, 0, 0.09);
    border-color: rgba(201, 162, 39, 0.7);
}
.mini-card::after {
    content: "查看详情 ›";
    position: absolute;
    right: 18px;
    bottom: 14px;
    font-size: 13px;
    color: var(--gold);
    letter-spacing: 1px;
    opacity: 0.75;
}
.mini-card:hover::after { opacity: 1; }
.mini-fig {
    position: relative;
    min-height: 190px;
}
.mini-fig img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
    border-radius: 10px;
}
.fig-cap {
    display: none;
}
.mini-body {
    align-self: center;
}
.mini-title {
    font-size: 21px;
    font-weight: 700;
    color: var(--indigo);
    margin-bottom: 12px;
    letter-spacing: 1px;
}
.mini-text {
    font-size: 15.5px;
    line-height: 1.95;
    color: var(--text);
}

/* ============ 朝代长文块（古代·迁徙史板块） ============ */
.dyn-block {
    background: var(--card);
    border: 1px solid rgba(36, 64, 108, 0.14);
    border-left: 4px solid var(--gold);
    border-radius: 14px;
    padding: 22px 26px 24px;
    margin-bottom: 26px;
    box-shadow: 0 3px 10px rgba(0, 0, 0, 0.05);
}
.dyn-title {
    font-family: var(--font-display);
    font-size: 25px;
    font-weight: 400;
    color: var(--indigo);
    letter-spacing: 2px;
    margin-bottom: 4px;
}
.dyn-time {
    font-family: var(--font-kai);
    font-size: 14px;
    color: var(--text-soft);
    letter-spacing: 1px;
    margin-left: 6px;
}
.dyn-sub {
    font-family: var(--font-kai);
    font-size: 17px;
    font-weight: 700;
    color: var(--indigo);
    letter-spacing: 1px;
    margin: 20px 0 8px;
    padding-left: 10px;
    border-left: 3px solid var(--gold);
}
.dyn-para {
    font-size: 15.5px;
    line-height: 2;
    color: var(--text);
    margin-bottom: 10px;
    text-indent: 2em;
}

/* ============ 词条详情弹层 ============ */
.detail-overlay {
    position: fixed;
    inset: 0;
    z-index: 2000;
    background: rgba(26, 48, 84, 0.6);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 24px;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.25s ease, visibility 0.25s ease;
    backdrop-filter: blur(3px);
}
.detail-overlay.open {
    opacity: 1;
    visibility: visible;
}
.detail-box {
    position: relative;
    width: min(860px, 100%);
    max-height: 88vh;
    overflow-y: auto;
    background: var(--card);
    border-radius: 16px;
    border-left: 4px solid var(--gold);
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.3);
    animation: fadeIn 0.25s ease;
}
.detail-close {
    position: absolute;
    top: 12px;
    right: 16px;
    width: 36px;
    height: 36px;
    border: none;
    border-radius: 50%;
    background: rgba(36, 64, 108, 0.9);
    color: #fff;
    font-size: 22px;
    line-height: 1;
    cursor: pointer;
    z-index: 5;
    transition: background 0.2s ease;
}
.detail-close:hover { background: var(--gold); }
.detail-fig {
    position: relative;
    height: 220px;
}
.detail-fig img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
    border-radius: 16px 16px 0 0;
}
.detail-fig .fig-cap {
    border-radius: 0;
}
.detail-body {
    padding: 24px 30px 30px;
}
.detail-title {
    font-size: 24px;
    font-weight: 700;
    color: var(--indigo);
    margin-bottom: 16px;
    letter-spacing: 1px;
}
.detail-content p {
    font-size: 15.5px;
    line-height: 2;
    color: var(--text);
    margin-bottom: 14px;
}

/* ============ 页脚 ============ */
.page-foot {
    text-align: center;
    padding: 26px 20px 40px;
    color: var(--text-soft);
    font-size: 14px;
    letter-spacing: 1px;
}

/* ============ 响应式 ============ */
@media (max-width: 720px) {
    .top-nav { flex-direction: column; gap: 8px; padding: 10px 16px; }
    .page { padding-top: 150px; }
    .nav-link { font-size: 15px; padding: 6px 14px; }
    .sec-title { font-size: 27px; }
    .group-title { font-size: 22px; margin: 32px 0 16px; }
    .sub-nav { flex-wrap: wrap; }
    .sub-nav a { flex: 1 1 40%; font-size: 14px; padding: 8px 4px; }
    .mini-card { grid-template-columns: 1fr; }
    .mini-fig { min-height: 170px; }
    .detail-fig { height: 160px; }
    .detail-body { padding: 18px 18px 22px; }
}