/* ========== 基础重置 ========== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Noto Sans SC', sans-serif;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: #F8F8F8;
    position: relative;
    overflow-x: hidden;
}

/* ========== 背景装饰圆 ========== */
.bg-decoration {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 0;
    overflow: hidden;
}

.circle {
    position: absolute;
    border-radius: 50%;
    opacity: 0.08;
}

.circle-1 {
    width: 500px;
    height: 500px;
    background-color: #A32A29;
    top: -150px;
    right: -100px;
}

.circle-2 {
    width: 300px;
    height: 300px;
    background-color: #A32A29;
    bottom: -80px;
    left: -60px;
}

.circle-3 {
    width: 200px;
    height: 200px;
    background-color: #A32A29;
    top: 50%;
    left: 60%;
}

/* ========== 主容器 ========== */
.container {
    position: relative;
    z-index: 1;
    max-width: 720px;
    width: 100%;
    padding: 60px 40px;
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
}

/* ========== 顶部区域 ========== */
.header {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 16px;
}

.logo-box {
    width: 90px;
    height: 42px;
    background-color: #A32A29;
    border-radius: 8px;
    display: grid;
    place-items: center;
    color: #fff;
    font-weight: 500;
    letter-spacing: 1px;
}

.tagline {
    color: #A32A29;
    font-size: 14px;
    letter-spacing: 2px;
    text-transform: uppercase;
}

/* ========== 核心内容 ========== */
.hero {
    margin-top: 48px;
}

h1 {
    font-family: 'Noto Serif SC', serif;
    font-size: 42px;
    font-weight: 600;
    margin-bottom: 16px;
    color: #222;
}

.desc-text {
    color: #666;
    line-height: 1.7;
    max-width: 520px;
    margin: 0 auto;
}

/* ========== 2x2 导航卡片矩阵 ========== */
.nav-grid {
    margin-top: 48px;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    width: 100%;
}

.nav-card {
    border: 1px solid #A32A29;
    border-radius: 10px;
    padding: 24px 20px;
    cursor: pointer;
    transition: all 0.3s ease;
    text-align: left;
}

.nav-card:hover {
    background-color: #A32A29;
    color: #fff;
    transform: translateY(-4px);
    box-shadow: 0 8px 24px rgba(163, 42, 41, 0.2);
}

.nav-card .icon {
    font-size: 22px;
    margin-bottom: 10px;
}

.nav-card h3 {
    font-size: 17px;
    margin-bottom: 6px;
}

.nav-card p {
    font-size: 13px;
    color: #777;
}

.nav-card:hover p {
    color: #f1f1f1;
}

/* ========== 建设中徽章 ========== */
.badge-building {
    display: inline-block;
    margin-top: 8px;
    padding: 2px 10px;
    font-size: 11px;
    color: #A32A29;
    border: 1px solid #A32A29;
    border-radius: 20px;
    letter-spacing: 1px;
}

.nav-card:hover .badge-building {
    color: #fff;
    border-color: #fff;
}

/* ========== 提示框（建设中弹窗） ========== */
.toast {
    position: fixed;
    bottom: 40px;
    left: 50%;
    transform: translateX(-50%) translateY(20px);
    background-color: #A32A29;
    color: #fff;
    padding: 12px 28px;
    border-radius: 8px;
    font-size: 14px;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.15);
    opacity: 0;
    transition: opacity 0.3s, transform 0.3s;
    pointer-events: none;
    z-index: 100;
}

.toast.show {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
}

/* ========== 页脚 ========== */
.footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 56px;
    width: 100%;
    font-size: 13px;
    color: #555;
}

.social-links a {
    display: inline-block;
    width: 34px;
    height: 34px;
    background-color: #A32A29;
    border-radius: 50%;
    color: white;
    text-align: center;
    line-height: 34px;
    margin-left: 8px;
    text-decoration: none;
    transition: 0.2s;
}

.social-links a:hover {
    opacity: 0.8;
    transform: scale(1.1);
}

/* ========== 移动端适配 ========== */
@media (max-width: 768px) {
    /* 修复：小屏垂直居中导致内容顶部被截断 */
    body {
        align-items: flex-start;
    }

    .container {
        padding: 32px 20px;
    }

    .tagline {
        font-size: 12px;
        letter-spacing: 1px;
    }

    .hero {
        margin-top: 32px;
    }

    h1 {
        font-size: 28px;
    }

    .nav-grid {
        grid-template-columns: 1fr;
        gap: 14px;
    }

    .nav-card {
        padding: 20px 16px;
    }

    .footer {
        flex-direction: column;
        gap: 12px;
        margin-top: 40px;
    }

    .circle-1 {
        width: 250px;
        height: 250px;
    }

    .circle-2 {
        width: 200px;
        height: 200px;
    }
}