/* ============================================================
   快积子 · 官网统一设计系统
   教育科技风格 · 大气 · 科技感
   ============================================================ */

:root {
    --bg0: #050a16;
    --bg1: #0a1224;
    --bg2: #0e1830;
    --panel: rgba(255, 255, 255, 0.045);
    --panel-strong: rgba(13, 22, 44, 0.86);
    --border: rgba(255, 255, 255, 0.09);
    --border-hi: rgba(0, 212, 255, 0.4);

    --text: #e9efff;
    --text-2: #c3cde6;
    --muted: #8b98ba;

    --cyan: #00d4ff;
    --blue: #4d8dff;
    --violet: #8b5cf6;
    --pink: #ff5fa2;
    --amber: #ffb84d;
    --green: #34d399;

    --grad-main: linear-gradient(135deg, #00d4ff 0%, #4d8dff 48%, #8b5cf6 100%);
    --grad-hot: linear-gradient(135deg, #ffb84d 0%, #ff5fa2 100%);
    --grad-text: linear-gradient(92deg, #00d4ff 0%, #6ea8ff 45%, #a78bfa 100%);

    --radius: 18px;
    --radius-sm: 12px;
    --shadow: 0 24px 60px rgba(2, 8, 24, 0.55);
    --font: 'Segoe UI', 'Microsoft YaHei', 'PingFang SC', 'Helvetica Neue', Arial, sans-serif;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
    font-family: var(--font);
    background: var(--bg0);
    color: var(--text);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    overflow-x: hidden;
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

/* ---------- 背景装饰：光晕 + 网格 ---------- */
.bg-orb {
    position: fixed;
    border-radius: 50%;
    filter: blur(110px);
    opacity: 0.5;
    z-index: -2;
    pointer-events: none;
}
.bg-orb-1 { width: 560px; height: 560px; top: -160px; left: -140px;
    background: radial-gradient(circle, rgba(0, 212, 255, 0.5), transparent 70%);
    animation: orbFloat 16s ease-in-out infinite alternate; }
.bg-orb-2 { width: 520px; height: 520px; top: 30%; right: -180px;
    background: radial-gradient(circle, rgba(139, 92, 246, 0.45), transparent 70%);
    animation: orbFloat 20s ease-in-out infinite alternate-reverse; }
.bg-orb-3 { width: 480px; height: 480px; bottom: -160px; left: 22%;
    background: radial-gradient(circle, rgba(77, 141, 255, 0.4), transparent 70%);
    animation: orbFloat 24s ease-in-out infinite alternate; }

.bg-grid {
    position: fixed;
    inset: 0;
    z-index: -3;
    background-image:
        linear-gradient(rgba(120, 160, 255, 0.05) 1px, transparent 1px),
        linear-gradient(90deg, rgba(120, 160, 255, 0.05) 1px, transparent 1px);
    background-size: 56px 56px;
    -webkit-mask-image: radial-gradient(ellipse 90% 70% at 50% 0%, #000 30%, transparent 100%);
    mask-image: radial-gradient(ellipse 90% 70% at 50% 0%, #000 30%, transparent 100%);
}

@keyframes orbFloat {
    0%   { transform: translate(0, 0) scale(1); }
    100% { transform: translate(40px, 30px) scale(1.12); }
}

/* ---------- 布局 ---------- */
.container { width: 100%; max-width: 1200px; margin: 0 auto; padding: 0 24px; }
main { flex: 1 0 auto; }
section { position: relative; }

.section { padding: 56px 0 24px; }
.section-head { text-align: center; margin-bottom: 42px; }
.eyebrow {
    display: inline-flex; align-items: center; gap: 8px;
    font-size: 13px; font-weight: 700; letter-spacing: 3px;
    text-transform: uppercase; color: var(--cyan);
    background: rgba(0, 212, 255, 0.08);
    border: 1px solid rgba(0, 212, 255, 0.25);
    padding: 6px 16px; border-radius: 999px; margin-bottom: 16px;
}
.section-title {
    font-size: clamp(26px, 4vw, 38px); font-weight: 800;
    background: var(--grad-text);
    -webkit-background-clip: text; background-clip: text;
    -webkit-text-fill-color: transparent;
    letter-spacing: 0.5px;
}
.section-sub { max-width: 720px; margin: 14px auto 0; color: var(--muted); font-size: 16px; }

/* ---------- 玻璃卡片 ---------- */
.glass {
    background: var(--panel);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
    box-shadow: var(--shadow);
    transition: transform 0.35s ease, border-color 0.35s ease, box-shadow 0.35s ease;
}
.glass:hover {
    transform: translateY(-6px);
    border-color: var(--border-hi);
    box-shadow: 0 30px 70px rgba(2, 10, 30, 0.65);
}

/* ---------- 顶部导航 ---------- */
.site-header {
    position: sticky; top: 0; z-index: 100;
    background: rgba(6, 11, 24, 0.72);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.07);
    margin-bottom: 8px;
}
.header-inner {
    max-width: 1200px; margin: 0 auto; padding: 14px 24px;
    display: flex; align-items: center; justify-content: space-between; gap: 18px; flex-wrap: wrap;
}
.brand { display: flex; align-items: center; gap: 14px; text-decoration: none; }
.brand-mark {
    width: 46px; height: 46px; border-radius: 13px;
    background: var(--grad-main);
    display: flex; align-items: center; justify-content: center;
    font-size: 22px; color: #fff;
    box-shadow: 0 8px 24px rgba(77, 141, 255, 0.45);
    flex-shrink: 0;
}
.brand-text { display: flex; flex-direction: column; }
.brand-name {
    font-size: 22px; font-weight: 800; color: #fff; letter-spacing: 1px; line-height: 1.2;
}
.brand-name span { background: var(--grad-text); -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent; }
.brand-tag { font-size: 11px; color: var(--muted); letter-spacing: 2px; }
.nav { display: flex; gap: 6px; flex-wrap: wrap; }
.nav a {
    color: var(--text-2); text-decoration: none; font-weight: 600; font-size: 15px;
    padding: 9px 16px; border-radius: 10px; transition: all 0.25s ease;
    border: 1px solid transparent;
}
.nav a:hover { color: #fff; background: rgba(255, 255, 255, 0.06); transform: translateY(-2px); }
.nav a.active {
    color: #fff;
    background: linear-gradient(135deg, rgba(0, 212, 255, 0.16), rgba(139, 92, 246, 0.16));
    border-color: rgba(0, 212, 255, 0.35);
    box-shadow: 0 0 18px rgba(0, 212, 255, 0.15);
}

/* ---------- 按钮 ---------- */
.btn {
    display: inline-flex; align-items: center; justify-content: center; gap: 10px;
    padding: 13px 26px; border-radius: 12px; font-size: 15px; font-weight: 700;
    text-decoration: none; cursor: pointer; border: 1px solid transparent;
    transition: all 0.3s ease; white-space: nowrap;
    font-family: var(--font);
}
.btn-primary {
    background: var(--grad-main); color: #fff;
    box-shadow: 0 10px 30px rgba(77, 141, 255, 0.35);
}
.btn-primary:hover { transform: translateY(-3px); box-shadow: 0 16px 40px rgba(77, 141, 255, 0.5); }
.btn-hot {
    background: var(--grad-hot); color: #fff;
    box-shadow: 0 10px 30px rgba(255, 95, 162, 0.3);
}
.btn-hot:hover { transform: translateY(-3px); box-shadow: 0 16px 40px rgba(255, 95, 162, 0.45); }
.btn-ghost {
    background: rgba(255, 255, 255, 0.05); color: var(--text);
    border-color: rgba(255, 255, 255, 0.16);
}
.btn-ghost:hover { border-color: rgba(0, 212, 255, 0.5); color: #fff; transform: translateY(-3px);
    background: rgba(0, 212, 255, 0.08); }
.btn-store {
    background: linear-gradient(135deg, #0f1b33 0%, #16294d 100%);
    border: 1px solid rgba(0, 212, 255, 0.35); color: #fff;
    box-shadow: 0 10px 26px rgba(0, 0, 0, 0.4);
}
.btn-store:hover { transform: translateY(-3px); border-color: #00d4ff;
    box-shadow: 0 14px 34px rgba(0, 212, 255, 0.28); }
.btn-store i { color: var(--cyan); font-size: 18px; }
.btn-lg { padding: 16px 34px; font-size: 16px; border-radius: 14px; }

/* ---------- 页头 Hero ---------- */
.page-hero {
    text-align: center; padding: 64px 20px 40px;
}
.page-hero h1 {
    font-size: clamp(30px, 5vw, 48px); font-weight: 800; line-height: 1.25;
    background: var(--grad-text);
    -webkit-background-clip: text; background-clip: text;
    -webkit-text-fill-color: transparent;
    margin: 18px 0;
}
.page-hero .lead {
    font-size: 18px; color: var(--text-2); max-width: 820px; margin: 0 auto 28px; line-height: 1.75;
}
.hero-cta { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }

/* ---------- 统计条 ---------- */
.stats-row {
    display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; margin-top: 44px;
}
.stat-card {
    background: var(--panel); border: 1px solid var(--border); border-radius: var(--radius-sm);
    padding: 22px 16px; text-align: center; backdrop-filter: blur(10px);
    transition: all 0.3s ease;
}
.stat-card:hover { border-color: var(--border-hi); transform: translateY(-4px); }
.stat-num {
    font-size: 30px; font-weight: 800;
    background: var(--grad-text); -webkit-background-clip: text; background-clip: text;
    -webkit-text-fill-color: transparent;
}
.stat-label { font-size: 13px; color: var(--muted); margin-top: 6px; }
@media (max-width: 800px) { .stats-row { grid-template-columns: repeat(2, 1fr); } }

/* ---------- 标签 chip ---------- */
.chip {
    display: inline-flex; align-items: center; gap: 6px;
    font-size: 13px; font-weight: 600; color: var(--text-2);
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.12);
    border-radius: 999px; padding: 6px 14px;
}
.chip i { color: var(--cyan); }

/* ---------- 页脚 ---------- */
.site-footer {
    margin-top: 60px; padding-top: 46px;
    background: rgba(5, 10, 22, 0.9);
    border-top: 1px solid rgba(255, 255, 255, 0.07);
    flex-shrink: 0;
}
.footer-grid {
    max-width: 1200px; margin: 0 auto; padding: 0 24px 34px;
    display: grid; grid-template-columns: 1.4fr 1fr 1fr; gap: 36px;
}
.footer-brand p { color: var(--muted); font-size: 14px; margin-top: 14px; max-width: 340px; line-height: 1.7; }
.footer-col h4 {
    font-size: 15px; font-weight: 700; color: #fff; margin-bottom: 16px; letter-spacing: 1px;
}
.footer-col a {
    display: block; color: var(--muted); text-decoration: none; font-size: 14px;
    padding: 5px 0; transition: color 0.2s ease;
}
.footer-col a:hover { color: var(--cyan); }
.footer-qr { display: flex; gap: 10px; flex-wrap: wrap; }
.footer-qr button {
    background: rgba(255, 255, 255, 0.05); color: var(--text-2);
    border: 1px solid var(--border); border-radius: 10px;
    padding: 10px 14px; font-size: 13px; font-weight: 600; cursor: pointer;
    display: inline-flex; align-items: center; gap: 8px; font-family: var(--font);
    transition: all 0.25s ease;
}
.footer-qr button:hover { color: #fff; border-color: rgba(0, 212, 255, 0.5); transform: translateY(-2px);
    background: rgba(0, 212, 255, 0.08); }
.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.06);
    padding: 18px 24px; text-align: center;
    color: var(--muted); font-size: 13px;
}
.footer-bottom a { color: var(--muted); text-decoration: none; }
.footer-bottom a:hover { color: var(--cyan); }
@media (max-width: 860px) { .footer-grid { grid-template-columns: 1fr; gap: 28px; } }

/* ---------- 弹窗（二维码 / 大图） ---------- */
.modal-overlay {
    position: fixed; inset: 0; background: rgba(3, 7, 18, 0.78);
    backdrop-filter: blur(6px); -webkit-backdrop-filter: blur(6px);
    display: flex; align-items: center; justify-content: center;
    z-index: 1000; opacity: 0; visibility: hidden; transition: all 0.3s ease;
    padding: 20px;
}
.modal-overlay.active { opacity: 1; visibility: visible; }
.modal {
    background: #f7f9ff; color: #1c2a4a; border-radius: 18px;
    padding: 26px; box-shadow: 0 30px 80px rgba(0, 0, 0, 0.6);
    transform: scale(0.92) translateY(12px); transition: transform 0.3s ease;
    max-width: 94vw; text-align: center; position: relative;
}
.modal-overlay.active .modal { transform: scale(1) translateY(0); }
.modal .close-btn {
    position: absolute; top: 12px; right: 14px; background: none; border: none;
    font-size: 20px; color: #8892b0; cursor: pointer; width: 32px; height: 32px;
    border-radius: 50%; transition: all 0.2s ease;
}
.modal .close-btn:hover { background: rgba(28, 42, 74, 0.08); color: #1c2a4a; }
.modal h3 { margin-bottom: 16px; font-size: 18px; }
.modal .qr-img {
    width: 240px; height: 240px; margin: 0 auto 14px; border-radius: 12px;
    overflow: hidden; background: #fff; border: 1px solid #e3e8f5;
    display: flex; align-items: center; justify-content: center;
}
.modal .qr-img img { width: 100%; height: 100%; object-fit: contain; }
.modal .qr-desc { font-size: 13px; color: #64708f; line-height: 1.7; }

/* 大图弹窗 */
.modal-dark { background: transparent; box-shadow: none; padding: 0; }
.modal-dark img { max-width: 92vw; max-height: 86vh; border-radius: 14px; box-shadow: 0 30px 90px rgba(0,0,0,0.7); }
.modal-dark .close-btn { color: #fff; font-size: 30px; top: -46px; right: 0; }

/* ---------- 入场动画 ---------- */
.reveal { opacity: 0; transform: translateY(26px); transition: opacity 0.6s ease, transform 0.6s ease; }
.reveal.visible { opacity: 1; transform: translateY(0); }

/* ---------- 通用小工具 ---------- */
.text-gradient { background: var(--grad-text); -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent; }
.mt-8 { margin-top: 8px; } .mt-16 { margin-top: 16px; } .mt-24 { margin-top: 24px; } .mt-32 { margin-top: 32px; }
.hide { display: none !important; }

/* ---------- 响应式 ---------- */
@media (max-width: 640px) {
    .container { padding: 0 16px; }
    .header-inner { padding: 12px 16px; justify-content: center; }
    .nav { justify-content: center; }
    .page-hero { padding: 44px 12px 28px; }
    .section { padding: 40px 0 16px; }
}