/* ===== 校园网助手 站点样式 ===== */
:root {
    --primary: #2196F3;
    --primary-dark: #1976D2;
    --success: #4CAF50;
    --text: #263238;
    --text-light: #78909C;
    --bg: #ffffff;
    --bg-soft: #f5f8fc;
    --border: #e3eef7;
    --shadow: 0 4px 24px rgba(33, 150, 243, .10);
    --radius: 14px;
    --maxw: 1080px;
}

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

html { scroll-behavior: smooth; }

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
                 "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    color: var(--text);
    background: var(--bg);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
}

a { text-decoration: none; color: var(--primary); }

img { max-width: 100%; }

/* ===== 顶栏导航 ===== */
.navbar {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(255, 255, 255, .92);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--border);
}

.navbar-inner {
    max-width: var(--maxw);
    margin: 0 auto;
    padding: 0 20px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.brand { font-size: 20px; font-weight: 700; color: var(--primary); }

.nav-links { display: flex; gap: 24px; align-items: center; }

.nav-links a { color: var(--text); font-size: 15px; transition: color .2s; }

.nav-links a:hover { color: var(--primary); }

.nav-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 24px;
    cursor: pointer;
    color: var(--text);
}

/* ===== Hero ===== */
.hero {
    background: linear-gradient(135deg, #E3F2FD 0%, #BBDEFB 55%, #90CAF9 100%);
    text-align: center;
    padding: 88px 20px 72px;
}

.hero h1 { font-size: 44px; color: var(--primary-dark); letter-spacing: 1px; }

.tagline { margin: 16px 0 30px; font-size: 18px; color: #455A64; }

.hero-actions { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }

.version-tag { margin-top: 22px; font-size: 13px; color: #607D8B; }

.version-tag a { color: #607D8B; text-decoration: underline; }

/* ===== 按钮 ===== */
.btn {
    display: inline-block;
    padding: 12px 30px;
    border-radius: 999px;
    font-size: 16px;
    font-weight: 600;
    transition: transform .15s, box-shadow .2s, background .2s;
}

.btn:hover { transform: translateY(-2px); }

.btn-primary { background: var(--primary); color: #fff; box-shadow: 0 6px 18px rgba(33,150,243,.35); }

.btn-primary:hover { background: var(--primary-dark); }

.btn-outline { border: 2px solid var(--primary-dark); color: var(--primary-dark); }

.btn-outline:hover { background: var(--primary-dark); color: #fff; }

.btn-success { background: var(--success); color: #fff; box-shadow: 0 6px 18px rgba(76,175,80,.35); }

/* ===== 自动签到 CTA（图标+按钮居中） ===== */
.signin-cta {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
}

.signin-icon { font-size: 44px; margin-bottom: 10px; }

/* ===== 区块 ===== */
.section { max-width: var(--maxw); margin: 0 auto; padding: 64px 20px; }

.section-accent { background: var(--bg-soft); border-radius: var(--radius); margin-top: 40px; }

.section-title { font-size: 28px; text-align: center; color: var(--primary-dark); }

.section-sub { text-align: center; color: var(--text-light); margin: 10px 0 36px; }

.section-note {
    text-align: center;
    color: var(--text-light);
    font-size: 14px;
    margin-top: 22px;
}

/* ===== 功能亮点（紧凑胶囊，不占大块） ===== */
.feature-grid {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 10px;
    margin-top: 6px;
}

.feature-card {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 16px;
    border-radius: 999px;
    border: 1px solid var(--border);
    background: #fff;
    transition: transform .2s, box-shadow .2s;
}

.feature-card:hover { transform: translateY(-2px); box-shadow: var(--shadow); }

.feature-icon { font-size: 17px; line-height: 1; }

.feature-card h3 { margin: 0; font-size: 14px; font-weight: 600; }

.feature-card p { display: none; }

/* 功能亮点区紧凑，突出下载与使用 */
#features { padding-top: 36px; padding-bottom: 28px; }

#features .section-title { font-size: 20px; }

/* ===== 下载卡片 ===== */
.download-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
    max-width: 720px;
    margin: 0 auto;
}

.download-card {
    display: block;
    background: #fff;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 30px 24px;
    text-align: center;
    transition: transform .2s, box-shadow .2s, border-color .2s;
    position: relative;
}

.download-card:hover { transform: translateY(-4px); box-shadow: var(--shadow); border-color: var(--primary); }

.download-card.offline { opacity: .75; }

.dl-icon { font-size: 42px; }

.download-card h3 { margin: 12px 0 4px; font-size: 20px; }

.dl-desc { font-size: 14px; color: var(--text-light); }

.dl-meta { font-size: 12px; color: var(--text-light); margin: 10px 0 14px; }

.dl-meta.ready { color: var(--success); }

.dl-meta.missing { color: #E65100; }

.dl-btn {
    display: inline-block;
    padding: 8px 26px;
    border-radius: 999px;
    background: var(--primary);
    color: #fff;
    font-size: 15px;
    font-weight: 600;
}

.download-card.offline .dl-btn { background: #B0BEC5; }

/* ===== 教程列表 ===== */
.tutorial-list { max-width: 720px; margin: 0 auto; display: flex; flex-direction: column; gap: 14px; }

.tutorial-item {
    display: flex;
    align-items: center;
    gap: 16px;
    background: #fff;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 18px 20px;
    transition: transform .2s, box-shadow .2s;
}

.tutorial-item:hover { transform: translateX(4px); box-shadow: var(--shadow); }

.t-ico { font-size: 30px; }

.t-body h3 { font-size: 16px; color: var(--text); }

.t-body p { font-size: 13px; color: var(--text-light); }

.t-arrow { margin-left: auto; color: var(--primary); font-size: 20px; }

/* ===== FAQ ===== */
.faq-list { max-width: 720px; margin: 0 auto; display: flex; flex-direction: column; gap: 12px; }

.faq-item {
    background: #fff;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
}

.faq-item summary {
    cursor: pointer;
    padding: 16px 20px;
    font-weight: 600;
    font-size: 15px;
    list-style: none;
    position: relative;
}

.faq-item summary::-webkit-details-marker { display: none; }

.faq-item summary::after {
    content: "+";
    position: absolute;
    right: 20px;
    top: 50%;
    transform: translateY(-50%);
    font-size: 20px;
    color: var(--primary);
    transition: transform .2s;
}

.faq-item[open] summary::after { transform: translateY(-50%) rotate(45deg); }

.faq-item p { padding: 0 20px 16px; font-size: 14px; color: var(--text-light); }

/* ===== 联系 ===== */
.contact-box {
    max-width: 560px;
    margin: 0 auto;
    background: #fff;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 26px;
}

.contact-item { font-size: 16px; margin-bottom: 10px; }

.contact-item:last-child { margin-bottom: 0; }

.contact-item strong { color: var(--primary-dark); }

/* 联系区大号微信 */
.contact-big {
    text-align: center;
    padding: 18px;
    margin-bottom: 16px;
    background: var(--bg-soft);
    border-radius: var(--radius);
    border: 1px solid var(--border);
}

.contact-big-label { font-size: 14px; color: var(--text-light); }

.contact-big-value {
    font-size: 26px;
    font-weight: 700;
    color: var(--primary-dark);
    letter-spacing: 1px;
    margin-top: 4px;
    word-break: break-all;
}

/* 联系区可点击项（点击跳转添加 QQ） */
a.contact-big { display: block; color: inherit; transition: border-color .2s, background .2s, transform .2s; }

a.contact-big:hover {
    border-color: var(--primary);
    background: #fff;
    transform: translateY(-2px);
}

.contact-big-go {
    display: inline-block;
    margin-left: 10px;
    font-size: 14px;
    font-weight: 600;
    color: var(--primary);
    letter-spacing: 0;
    white-space: nowrap;
}

a.contact-big:hover .contact-big-go { text-decoration: underline; }

/* ===== Hero 客服醒目条 ===== */
.hero-contact {
    display: inline-flex;
    align-items: center;
    flex-wrap: wrap;
    justify-content: center;
    gap: 8px;
    margin-top: 22px;
    background: rgba(255, 255, 255, .88);
    border-radius: 999px;
    padding: 10px 22px;
    font-size: 15px;
    color: var(--text);
    box-shadow: 0 4px 16px rgba(25, 118, 210, .18);
}

.hero-contact strong { color: var(--primary-dark); font-size: 17px; }

/* Hero 条里的可点击 QQ（下划虚线提示可点，hover 变实线） */
.hero-contact-link { border-bottom: 1px dashed var(--primary); transition: border-color .2s; }

.hero-contact-link:hover { border-bottom-style: solid; border-bottom-color: var(--primary-dark); }

.hero-contact-24h { color: var(--success); font-weight: 600; }

/* ===== 悬浮客服按钮 ===== */
.float-contact {
    position: fixed;
    right: 20px;
    bottom: 24px;
    z-index: 200;
    background: var(--success);
    color: #fff;
    padding: 12px 22px;
    border-radius: 999px;
    font-size: 15px;
    font-weight: 600;
    box-shadow: 0 6px 20px rgba(76, 175, 80, .4);
    transition: transform .2s, background .2s;
}

.float-contact:hover { transform: translateY(-2px); color: #fff; background: #43A047; }

/* ===== 页脚 ===== */
.footer { border-top: 1px solid var(--border); padding: 26px 20px; text-align: center; }

.footer-inner { max-width: var(--maxw); margin: 0 auto; color: var(--text-light); font-size: 14px; }

.footer-inner p + p { margin-top: 4px; }

/* ===== 教程页通用 ===== */
.page-hero {
    background: linear-gradient(135deg, #E3F2FD 0%, #BBDEFB 100%);
    padding: 40px 20px;
    text-align: center;
}

.page-hero h1 { font-size: 28px; color: var(--primary-dark); }

.page-hero p { color: #546E7A; margin-top: 8px; }

.crumbs {
    max-width: var(--maxw);
    margin: 18px auto 0;
    padding: 0 20px;
    font-size: 13px;
    color: var(--text-light);
}

.crumbs a { color: var(--primary); }

.tutorial-content {
    max-width: 720px;
    margin: 30px auto 60px;
    padding: 0 20px;
}

.tutorial-content h2 {
    font-size: 20px;
    color: var(--primary-dark);
    margin: 30px 0 12px;
    padding-left: 12px;
    border-left: 4px solid var(--primary);
}

.tutorial-content p, .tutorial-content li { font-size: 15px; color: #455A64; }

.tutorial-content ul, .tutorial-content ol { padding-left: 22px; margin: 8px 0; }

.tutorial-content li { margin: 6px 0; }

.tutorial-content .hint {
    background: #E3F2FD;
    border-radius: 8px;
    padding: 12px 16px;
    font-size: 14px;
    margin: 14px 0;
    color: #1565C0;
}

.tutorial-content .warn {
    background: #FFF3E0;
    border-radius: 8px;
    padding: 12px 16px;
    font-size: 14px;
    margin: 14px 0;
    color: #E65100;
}

.back-home {
    display: inline-block;
    margin-top: 36px;
    color: var(--primary);
    font-size: 15px;
}

/* ===== 响应式 ===== */
@media (max-width: 820px) {
    .feature-grid { grid-template-columns: repeat(2, 1fr); }
    .hero h1 { font-size: 34px; }
    .section { padding: 48px 16px; }
}

@media (max-width: 560px) {
    .nav-links {
        display: none;
        position: absolute;
        top: 60px;
        left: 0;
        right: 0;
        background: #fff;
        flex-direction: column;
        gap: 0;
        border-bottom: 1px solid var(--border);
        box-shadow: var(--shadow);
    }
    .nav-links.open { display: flex; }
    .nav-links a { padding: 14px 20px; width: 100%; }
    .nav-toggle { display: block; }
    .download-grid { grid-template-columns: 1fr; }
    .feature-grid { grid-template-columns: 1fr; }
    .hero { padding: 60px 16px 48px; }
    .hero h1 { font-size: 30px; }
    .hero-contact { flex-wrap: wrap; justify-content: center; gap: 4px 8px; padding: 8px 16px; }
    .contact-big-value { font-size: 22px; }
    .float-contact { right: 14px; bottom: 16px; padding: 10px 16px; font-size: 14px; }
}