/* ===== 全局变量与重置 ===== */
:root {
    --primary-blue: #2A6DF4;
    --primary-light: #E9F0FF;
    --bg-gradient-start: #F5F9FF;
    --bg-gradient-end: #FFFFFF;
    --text-primary: #1E2A3A;
    --text-secondary: #546E7A;
    --white: #FFFFFF;
    --shadow-sm: 0 10px 30px -10px rgba(42, 109, 244, 0.2);
    --shadow-hover: 0 20px 40px -12px rgba(42, 109, 244, 0.35);
    --border-radius-card: 28px;
    --border-radius-btn: 40px;
    --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
}

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

body {
    font-family: var(--font-sans);
    background: linear-gradient(145deg, var(--bg-gradient-start), var(--bg-gradient-end));
    color: var(--text-primary);
    line-height: 1.5;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

main {
    flex: 1;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ===== 毛玻璃卡片效果 ===== */
.glass-card {
    background: rgba(255, 255, 255, 0.75);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid rgba(255, 255, 255, 0.5);
    border-radius: var(--border-radius-card);
    box-shadow: var(--shadow-sm);
    transition: all 0.4s cubic-bezier(0.2, 0, 0, 1);
}

.glass-card:hover {
    box-shadow: var(--shadow-hover);
    border-color: rgba(42, 109, 244, 0.2);
    transform: translateY(-4px);
}

/* ===== 动画 ===== */
.fade-in-up {
    opacity: 0;
    transform: translateY(20px);
    animation: fadeInUp 0.8s ease forwards;
}

@keyframes fadeInUp {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ===== 头部导航 ===== */
.site-header {
    position: sticky;
    top: 0;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid rgba(42, 109, 244, 0.1);
    z-index: 100;
    padding: 12px 0;
}

.header-flex {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

/* Logo适配 - 控制大图尺寸 */
.nav-logo {
    height: 48px;
    width: auto;
    max-width: 160px;
    object-fit: contain;
    transition: transform 0.2s ease;
}

.nav-logo:hover {
    transform: scale(1.02);
}

/* 导航菜单 */
.main-nav ul {
    display: flex;
    list-style: none;
    gap: 8px;
}

.main-nav a {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 10px 18px;
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 500;
    border-radius: 40px;
    transition: all 0.2s ease;
    white-space: nowrap;
}

.main-nav a i {
    font-size: 1.1rem;
    color: var(--primary-blue);
    opacity: 0.8;
}

.main-nav a:hover,
.main-nav a.active {
    background: var(--primary-blue);
    color: white;
}

.main-nav a:hover i,
.main-nav a.active i {
    color: white;
    opacity: 1;
}

.mobile-nav-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.8rem;
    color: var(--primary-blue);
    cursor: pointer;
    padding: 8px;
}

/* ===== 英雄区域 (大Logo) ===== */
.hero-section {
    padding: 40px 0 20px;
    text-align: center;
}

.hero-container {
    display: flex;
    justify-content: center;
}

.hero-logo {
    width: 200px;
    height: auto;
    max-width: 80%;
    margin-bottom: 20px;
    filter: drop-shadow(0 10px 20px rgba(42, 109, 244, 0.15));
    animation: float 6s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-8px); }
}

.hero-content h1 {
    font-size: clamp(2rem, 8vw, 3rem);
    font-weight: 700;
    margin-bottom: 12px;
    background: linear-gradient(135deg, var(--primary-blue), #4A90E2);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-tagline {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: 32px;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

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

/* ===== 按钮 ===== */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 32px;
    border-radius: var(--border-radius-btn);
    font-weight: 600;
    text-decoration: none;
    transition: all 0.3s ease;
    border: none;
    cursor: pointer;
}

.btn-primary {
    background: var(--primary-blue);
    color: white;
    box-shadow: 0 8px 20px -8px var(--primary-blue);
}

.btn-primary:hover {
    background: #1A5BD9;
    transform: scale(1.05);
    box-shadow: 0 12px 28px -8px var(--primary-blue);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(4px);
    color: var(--primary-blue);
    border: 1.5px solid rgba(42, 109, 244, 0.3);
}

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

.btn-small {
    padding: 10px 20px;
    font-size: 0.9rem;
}

/* ===== 承诺卡片 (第二个Logo) ===== */
.promise-section {
    padding: 20px 0;
}

.promise-card {
    padding: 40px;
    margin: 20px 0;
}

.promise-header {
    display: flex;
    align-items: center;
    gap: 16px;
    margin-bottom: 24px;
    flex-wrap: wrap;
}

.promise-logo {
    height: 60px;
    width: auto;
}

.promise-header h2 {
    font-size: 1.8rem;
    color: var(--primary-blue);
}

.promise-text {
    font-size: 1.1rem;
    margin-bottom: 24px;
    color: var(--text-primary);
}

.highlight {
    color: var(--primary-blue);
    font-weight: 600;
}

.promise-notice {
    background: var(--primary-light);
    padding: 16px 24px;
    border-radius: 60px;
    display: inline-flex;
    align-items: center;
    gap: 12px;
    flex-wrap: wrap;
}

/* ===== 通用区块 ===== */
.section-block {
    padding: 60px 0;
}

.light-bg {
    background: rgba(42, 109, 244, 0.02);
}

.section-title {
    font-size: 2rem;
    margin-bottom: 32px;
    display: flex;
    align-items: center;
    gap: 12px;
    color: var(--primary-blue);
}

.section-title i {
    font-size: 2rem;
}

/* 群聊卡片 */
.group-card {
    padding: 40px;
}

.badge {
    background: var(--primary-blue);
    color: white;
    padding: 6px 16px;
    border-radius: 40px;
    display: inline-block;
    margin-bottom: 20px;
}

.contact-method {
    background: var(--primary-light);
    padding: 16px 20px;
    border-radius: 60px;
    display: flex;
    align-items: center;
    gap: 12px;
    margin: 20px 0;
    font-size: 1.1rem;
}

.contact-method i {
    font-size: 1.8rem;
    color: var(--primary-blue);
}

.requirement-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    margin: 20px 0;
}

.tag {
    background: rgba(42, 109, 244, 0.1);
    padding: 6px 16px;
    border-radius: 40px;
    display: inline-flex;
    align-items: center;
    gap: 6px;
}

.tag i {
    color: var(--primary-blue);
}

.warning-note {
    color: #D92D20;
    background: rgba(217, 45, 32, 0.05);
    padding: 12px;
    border-radius: 12px;
    border-left: 4px solid #D92D20;
}

/* 规则卡片 */
.rules-card {
    padding: 40px;
}

.doc-link {
    display: inline-block;
    margin: 20px 0;
    padding: 12px 24px;
    background: var(--primary-light);
    border-radius: 60px;
    text-decoration: none;
    color: var(--primary-blue);
    font-weight: 500;
}

.rule-list {
    list-style: none;
    margin-top: 24px;
}

.rule-list li {
    margin: 16px 0;
    display: flex;
    align-items: center;
    gap: 12px;
}

.rule-icon-ban { color: #D92D20; }
.rule-icon-ok { color: #2E7D32; }
.rule-icon-warn { color: #ED6C02; }

/* 反馈网格 */
.feedback-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
}

.feedback-card {
    padding: 40px 24px;
    text-align: center;
    transition-delay: calc(0.05s * var(--index, 0));
}

.feedback-card i {
    font-size: 3rem;
    color: var(--primary-blue);
    margin-bottom: 20px;
}

.email-wrapper {
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin-top: 16px;
}

.email-address {
    color: var(--primary-blue);
    text-decoration: none;
    word-break: break-all;
}

.btn-copy {
    background: var(--primary-light);
    border: 1px solid var(--primary-blue);
    border-radius: 40px;
    padding: 8px 16px;
    color: var(--primary-blue);
    cursor: pointer;
    font-weight: 500;
    transition: all 0.2s;
    align-self: center;
}

.btn-copy:hover {
    background: var(--primary-blue);
    color: white;
}

/* 关于卡片 */
.about-card {
    padding: 40px;
}

.disclaimer-box {
    background: rgba(42, 109, 244, 0.03);
    padding: 24px;
    border-radius: 20px;
    margin: 24px 0;
}

.disclaimer-box ol {
    margin-left: 24px;
    margin-top: 12px;
}

.disclaimer-box li {
    margin: 8px 0;
}

.signature {
    text-align: right;
    font-style: italic;
    margin: 24px 0;
}

.activity-link {
    background: linear-gradient(145deg, var(--primary-light), white);
    padding: 16px 24px;
    border-radius: 60px;
    border: 1px solid rgba(42, 109, 244, 0.2);
}

/* ===== 底部 ===== */
.site-footer {
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(16px);
    border-top: 1px solid rgba(42, 109, 244, 0.1);
    padding: 32px 0;
    margin-top: 40px;
}

.footer-container {
    text-align: center;
}

.footer-links {
    margin-bottom: 16px;
    display: flex;
    justify-content: center;
    align-items: center;
    flex-wrap: wrap;
    gap: 16px;
}

.footer-links a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: color 0.2s;
}

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

.sep {
    color: var(--primary-blue);
    opacity: 0.3;
}

.footer-copyright {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

/* ===== 响应式设计 (重点优化移动端) ===== */
@media (max-width: 768px) {
    .container {
        padding: 0 16px;
    }

    /* 移动端菜单 */
    .mobile-nav-toggle {
        display: block;
    }

    .main-nav {
        position: fixed;
        top: 76px;
        left: -100%;
        width: 85%;
        max-width: 320px;
        height: calc(100vh - 76px);
        background: rgba(255, 255, 255, 0.95);
        backdrop-filter: blur(20px);
        padding: 24px 16px;
        transition: left 0.3s ease;
        box-shadow: 4px 0 20px rgba(0,0,0,0.05);
        border-right: 1px solid rgba(42, 109, 244, 0.1);
    }

    .main-nav.active {
        left: 0;
    }

    .main-nav ul {
        flex-direction: column;
        gap: 8px;
    }

    .main-nav a {
        padding: 14px 20px;
        font-size: 1.1rem;
    }

    /* 英雄区域调整 */
    .hero-logo {
        width: 160px;
    }

    .hero-buttons {
        flex-direction: column;
        align-items: stretch;
        max-width: 320px;
        margin: 0 auto;
    }

    .btn {
        justify-content: center;
    }

    /* 卡片内边距调整 */
    .promise-card,
    .group-card,
    .rules-card,
    .about-card {
        padding: 28px 20px;
    }

    .promise-header {
        flex-direction: column;
        text-align: center;
    }

    .promise-notice {
        border-radius: 24px;
        padding: 16px;
        width: 100%;
        justify-content: center;
    }

    .section-title {
        font-size: 1.8rem;
    }

    /* 反馈卡片 */
    .feedback-grid {
        grid-template-columns: 1fr;
    }

    /* 底部链接 */
    .footer-links {
        flex-direction: column;
        gap: 12px;
    }

    .sep {
        display: none;
    }
}

/* 针对超小屏优化 */
@media (max-width: 380px) {
    .hero-logo {
        width: 130px;
    }

    .hero-content h1 {
        font-size: 1.8rem;
    }
}