/* ==========================================================================
   华师云甄选 · 全局设计系统
   色调：HEDU 蓝色调（深海蓝 + 科技蓝）
   字体：现代无衬线，标题加粗加大
   布局：全页宽 1440px，更宽松的留白与栅格
   ========================================================================== */

:root {
    /* ===== 主色 - 深海蓝（HEDU 集团风格）** ===== */
    --color-primary: #0A2540;            /* 主蓝 - 深海蓝 */
    --color-primary-dark: #061B30;       /* 极深蓝（点击替代）*/
    --color-primary-light: #1A4F7A;      /* 中蓝 */

    /* ===== 辅色 - 科技蓝（强调/按钮/链接）** ===== */
    --color-accent: #1E88E5;             /* 科技蓝 */
    --color-accent-dark: #1565C0;        /* 深科技蓝 */
    --color-accent-light: #64B5F6;       /* 浅科技蓝 */
    --color-cyan: #00ACC1;               /* 青蓝（点缀）*/

    /* ===== 中性色 ===== */
    --color-bg: #FFFFFF;                 /* 主背景 */
    --color-bg-alt: #F8FAFC;             /* 浅灰背景 */
    --color-bg-blue: #F0F7FF;            /* 极浅蓝背景 */
    --color-text: #0F172A;               /* 主文字 */
    --color-text-muted: #64748B;         /* 次要文字 */
    --color-text-light: #94A3B8;         /* 浅文字 */
    --color-border: #E2E8F0;             /* 主边框 */
    --color-border-light: #F1F5F9;      /* 浅边框 */
    --color-white: #FFFFFF;

    /* ===== 字体方案 ===== */
    --font-sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", "Segoe UI", Arial, sans-serif;
    --font-display: "PingFang SC", "Microsoft YaHei", -apple-system, BlinkMacSystemFont, sans-serif;
    --font-serif: "Source Han Serif SC", "Noto Serif SC", "Songti SC", serif;

    /* ===== 间距 ===== */
    --container-max: 1440px;
    --container-padding: clamp(28px, 5vw, 80px);
    --section-padding: clamp(80px, 10vw, 140px);

    /* ===== 阴影 ===== */
    --shadow-sm: 0 1px 3px rgba(10, 37, 64, 0.06), 0 1px 2px rgba(10, 37, 64, 0.04);
    --shadow-md: 0 4px 16px rgba(10, 37, 64, 0.08), 0 2px 4px rgba(10, 37, 64, 0.04);
    --shadow-lg: 0 20px 48px rgba(10, 37, 64, 0.12), 0 4px 12px rgba(10, 37, 64, 0.06);
    --shadow-xl: 0 32px 80px rgba(10, 37, 64, 0.16), 0 8px 16px rgba(10, 37, 64, 0.08);

    /* ===== 过渡 ===== */
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: all 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ============== 重置 ============== */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: var(--font-sans);
    color: var(--color-text);
    background-color: var(--color-bg);
    line-height: 1.75;
    font-size: 15px;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

img { max-width: 100%; height: auto; display: block; }
a { color: inherit; text-decoration: none; transition: var(--transition); }
button { font-family: inherit; cursor: pointer; border: none; background: none; }
ul, ol { list-style: none; }

::selection {
    background-color: var(--color-primary);
    color: var(--color-white);
}

/* ============== 容器（全页宽） ============== */
.container {
    width: 100%;
    max-width: var(--container-max);
    margin: 0 auto;
    padding-left: var(--container-padding);
    padding-right: var(--container-padding);
}

.container-fluid {
    width: 100%;
    padding-left: var(--container-padding);
    padding-right: var(--container-padding);
}

/* ============== 排版 ============== */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-display);
    font-weight: 700;
    line-height: 1.25;
    color: var(--color-primary);
    letter-spacing: -0.02em;
}

h1 {
    font-size: clamp(2.2rem, 4.5vw, 3.4rem);
    font-weight: 800;
    letter-spacing: -0.03em;
}
h2 {
    font-size: clamp(1.55rem, 2.8vw, 2.15rem);
    letter-spacing: -0.025em;
}
h3 {
    font-size: clamp(1.15rem, 1.8vw, 1.4rem);
}
h4 {
    font-size: clamp(1rem, 1.4vw, 1.15rem);
}

p {
    margin-bottom: 1rem;
    color: var(--color-text-muted);
}

.text-accent { color: var(--color-accent); }
.text-primary { color: var(--color-primary); }
.text-muted { color: var(--color-text-muted); }

/* ============== 按钮 ============== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 13px 30px;
    font-size: 0.95rem;
    font-weight: 600;
    border-radius: 6px;
    transition: var(--transition);
    cursor: pointer;
    letter-spacing: 0.02em;
    white-space: nowrap;
    text-decoration: none;
    line-height: 1;
}

.btn-primary {
    background-color: var(--color-primary);
    color: var(--color-white);
    border: 2px solid var(--color-primary);
}
.btn-primary:hover {
    background-color: var(--color-primary-dark);
    border-color: var(--color-primary-dark);
    transform: translateY(-2px);
    box-shadow: 0 12px 24px rgba(10, 37, 64, 0.2);
}

.btn-accent {
    background-color: var(--color-accent);
    color: var(--color-white);
    border: 2px solid var(--color-accent);
}
.btn-accent:hover {
    background-color: var(--color-accent-dark);
    border-color: var(--color-accent-dark);
    transform: translateY(-2px);
    box-shadow: 0 12px 24px rgba(30, 136, 229, 0.25);
}

.btn-outline {
    background-color: transparent;
    color: var(--color-primary);
    border: 2px solid var(--color-primary);
}
.btn-outline:hover {
    background-color: var(--color-primary);
    color: var(--color-white);
    transform: translateY(-2px);
}

.btn-ghost {
    background-color: transparent;
    color: var(--color-primary);
    border: 2px solid var(--color-border);
}
.btn-ghost:hover {
    background-color: var(--color-bg-alt);
    border-color: var(--color-primary);
}

.btn-ghost-light {
    background-color: rgba(255, 255, 255, 0.08);
    color: var(--color-white);
    border: 2px solid rgba(255, 255, 255, 0.65);
}
.btn-ghost-light:hover {
    background-color: var(--color-white);
    color: var(--color-primary);
    border-color: var(--color-white);
}

/* ============== 顶部导航 ============== */
.site-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background-color: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(24px) saturate(180%);
    -webkit-backdrop-filter: blur(24px) saturate(180%);
    border-bottom: 1px solid transparent;
    transition: var(--transition);
}

.site-header.scrolled {
    background-color: rgba(255, 255, 255, 0.96);
    border-bottom-color: var(--color-border);
    box-shadow: var(--shadow-sm);
}

.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 84px;
}

.brand {
    display: flex;
    align-items: center;
    gap: 12px;
    font-family: var(--font-display);
    font-size: 1.15rem;
    font-weight: 700;
    color: var(--color-primary);
}

.brand-img {
    gap: 0;
}

.brand-logo {
    height: 46px;
    width: auto;
    display: block;
}

.brand-mark {
    width: 38px;
    height: 38px;
    border-radius: 8px;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-accent) 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-white);
    font-family: var(--font-serif);
    font-size: 1.05rem;
    font-weight: 700;
    box-shadow: var(--shadow-sm);
}

.nav-menu {
    display: flex;
    gap: 4px;
    align-items: center;
}

.nav-link {
    padding: 10px 20px;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--color-text);
    position: relative;
    border-radius: 6px;
    transition: var(--transition);
}

.nav-link:hover {
    color: var(--color-primary);
    background-color: var(--color-bg-alt);
}

.nav-link.active {
    color: var(--color-primary);
    font-weight: 600;
}

.nav-link.active::after {
    content: '';
    position: absolute;
    left: 50%;
    bottom: -2px;
    width: 20px;
    height: 3px;
    background-color: var(--color-accent);
    transform: translateX(-50%);
    border-radius: 2px;
}

.nav-cta {
    margin-left: 12px;
}

.nav-toggle {
    display: none;
    width: 32px;
    height: 32px;
    flex-direction: column;
    justify-content: center;
    gap: 5px;
}
.nav-toggle span {
    width: 24px;
    height: 2px;
    background-color: var(--color-primary);
    transition: var(--transition);
}

/* ============== 通用区块 ============== */
.section {
    padding: var(--section-padding) 0;
}

.section-alt {
    background-color: var(--color-bg-alt);
}

.section-blue {
    background: linear-gradient(180deg, var(--color-bg-blue) 0%, var(--color-bg) 100%);
}

.section-dark {
    background-color: var(--color-primary);
    color: var(--color-white);
}

.section-dark h1,
.section-dark h2,
.section-dark h3,
.section-dark h4 {
    color: var(--color-white);
}

.section-header {
    text-align: center;
    margin-bottom: clamp(48px, 6vw, 88px);
}

.section-eyebrow {
    display: inline-block;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--color-accent);
    letter-spacing: 0.2em;
    text-transform: uppercase;
    margin-bottom: 18px;
    padding: 7px 18px;
    background-color: rgba(30, 136, 229, 0.08);
    border-radius: 100px;
}

.section-title {
    margin-bottom: 20px;
    color: var(--color-primary);
}

.section-subtitle {
    font-size: clamp(0.95rem, 1.2vw, 1.05rem);
    color: var(--color-text-muted);
    max-width: 720px;
    margin: 0 auto;
    line-height: 1.8;
}

.section-dark .section-subtitle { color: rgba(255, 255, 255, 0.75); }
.section-dark .section-eyebrow {
    color: var(--color-accent-light);
    background-color: rgba(30, 136, 229, 0.15);
}

/* ============== Footer ============== */
.site-footer {
    background-color: var(--color-primary-dark);
    color: rgba(255, 255, 255, 0.7);
    padding: clamp(60px, 8vw, 96px) 0 28px;
}

.footer-grid {
    display: grid;
    grid-template-columns: 1.6fr repeat(3, 1fr);
    gap: 56px;
    margin-bottom: 56px;
}

.footer-brand .brand {
    color: var(--color-white);
    margin-bottom: 20px;
}

.footer-brand p {
    color: rgba(255, 255, 255, 0.6);
    font-size: 0.92rem;
    line-height: 1.8;
    max-width: 380px;
}

.footer-col h5 {
    color: var(--color-white);
    font-family: var(--font-sans);
    font-size: 0.95rem;
    font-weight: 600;
    margin-bottom: 22px;
    letter-spacing: 0.05em;
}

.footer-col ul li {
    margin-bottom: 14px;
    font-size: 0.92rem;
}

.footer-col a {
    color: rgba(255, 255, 255, 0.6);
    transition: var(--transition);
}

.footer-col a:hover {
    color: var(--color-accent-light);
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.08);
    padding-top: 28px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 16px;
    font-size: 0.85rem;
    color: rgba(255, 255, 255, 0.5);
}

.footer-bottom .icp a {
    color: rgba(255, 255, 255, 0.5);
    font-weight: 500;
    letter-spacing: 0.02em;
}

.footer-bottom .icp a:hover {
    color: var(--color-accent-light);
}

/* ============== 工具类 ============== */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.8s ease, transform 0.8s ease;
}
.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ============== 响应式 ============== */
@media (max-width: 1024px) {
    .footer-grid {
        grid-template-columns: 1fr 1fr;
        gap: 36px;
    }
}

@media (max-width: 768px) {
    .nav-toggle { display: flex; }
    .nav-menu {
        position: fixed;
        top: 84px;
        left: 0;
        right: 0;
        background-color: var(--color-white);
        flex-direction: column;
        padding: 24px;
        gap: 0;
        border-bottom: 1px solid var(--color-border);
        box-shadow: var(--shadow-md);
        transform: translateY(-120%);
        opacity: 0;
        pointer-events: none;
        transition: var(--transition);
    }
    .nav-menu.open {
        transform: translateY(0);
        opacity: 1;
        pointer-events: auto;
    }
    .nav-link {
        width: 100%;
        text-align: center;
        padding: 16px;
    }
    .nav-cta { margin-left: 0; margin-top: 8px; width: 100%; }
    .nav-cta .btn { width: 100%; }
    .footer-grid {
        grid-template-columns: 1fr;
    }
    .footer-bottom {
        flex-direction: column;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .container-fluid { padding-left: 20px; padding-right: 20px; }
    .nav { height: 68px; }
    .nav-menu { top: 68px; }
    .btn { padding: 14px 28px; font-size: 0.95rem; }
    .brand-mark { width: 38px; height: 38px; font-size: 1.1rem; }
    .brand { font-size: 1.1rem; }
    .brand-logo { height: 36px; }
}

/* ============== 页面顶部留白（因为有固定头部） ============== */
main { padding-top: 84px; }
@media (max-width: 480px) {
    main { padding-top: 68px; }
}