* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background: #f4f7fc;
    color: #333;
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 导航 */
header {
    background: linear-gradient(135deg, #1a1a2e, #16213e);
    color: #fff;
    padding: 15px 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 15px rgba(0,0,0,0.3);
}

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

.logo {
    font-size: 1.8rem;
    font-weight: 700;
    letter-spacing: 1px;
}

.logo i {
    color: #00d4ff;
    margin-right: 10px;
}

.nav-links {
    list-style: none;
    display: flex;
    gap: 20px;
}

.nav-links a {
    color: #ddd;
    text-decoration: none;
    font-size: 1rem;
    transition: color 0.3s, border-bottom 0.3s;
    padding-bottom: 5px;
    border-bottom: 2px solid transparent;
}

.nav-links a:hover {
    color: #00d4ff;
    border-bottom-color: #00d4ff;
}

.hamburger {
    display: none;
    font-size: 1.8rem;
    cursor: pointer;
    color: #fff;
}

/* 英雄区 */
.hero {
    background: linear-gradient(135deg, #0f2027, #203a43, #2c5364);
    color: #fff;
    padding: 80px 20px;
    text-align: center;
}

.hero h1 {
    font-size: 2.5rem;
    margin-bottom: 20px;
    font-weight: 700;
}

.hero p {
    font-size: 1.2rem;
    max-width: 800px;
    margin: 0 auto 30px;
    opacity: 0.9;
}

.hero-buttons .btn {
    margin: 10px;
    padding: 14px 30px;
    border-radius: 30px;
    text-decoration: none;
    font-weight: 600;
    display: inline-block;
    transition: transform 0.3s, box-shadow 0.3s;
}

.btn-primary {
    background: #00d4ff;
    color: #1a1a2e;
}

.btn-secondary {
    background: rgba(255,255,255,0.2);
    color: #fff;
    border: 2px solid #fff;
}

.btn-primary:hover, .btn-secondary:hover {
    transform: translateY(-3px);
    box-shadow: 0 10px 20px rgba(0,0,0,0.3);
}

/* 功能卡片 */
.features {
    padding: 60px 20px;
    background: #fff;
}

.features h2 {
    text-align: center;
    font-size: 2rem;
    margin-bottom: 40px;
    color: #1a1a2e;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
}

.feature-card {
    background: #f9f9ff;
    border-radius: 16px;
    padding: 30px 20px;
    box-shadow: 0 8px 20px rgba(0,0,0,0.05);
    transition: transform 0.3s, box-shadow 0.3s;
    text-align: center;
    border: 1px solid #eef;
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 30px rgba(0,0,0,0.1);
}

.feature-card i {
    font-size: 2.5rem;
    color: #00d4ff;
    margin-bottom: 15px;
}

.feature-card h3 {
    font-size: 1.3rem;
    margin-bottom: 10px;
    color: #16213e;
}

.feature-card p {
    color: #666;
    font-size: 0.95rem;
}

/* 统计 */
.stats {
    background: linear-gradient(135deg, #0f2027, #203a43);
    color: #fff;
    padding: 40px 20px;
    display: flex;
    justify-content: center;
    gap: 60px;
    flex-wrap: wrap;
}

.stat-item {
    font-size: 1.5rem;
    font-weight: 600;
}

.stat-item i {
    margin-right: 10px;
    color: #00d4ff;
}

/* 页脚 */
footer {
    background: #1a1a2e;
    color: #ccc;
    text-align: center;
    padding: 20px;
}

footer a {
    color: #00d4ff;
    text-decoration: none;
}

/* 登录页 */
.login-page {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background: linear-gradient(135deg, #0f2027, #203a43);
}

.login-container {
    background: #fff;
    padding: 40px;
    border-radius: 20px;
    box-shadow: 0 20px 40px rgba(0,0,0,0.2);
    width: 360px;
    text-align: center;
}

.login-container h2 {
    margin-bottom: 20px;
    color: #1a1a2e;
}

.login-container input {
    width: 100%;
    padding: 12px;
    margin: 10px 0;
    border: 1px solid #ddd;
    border-radius: 8px;
    font-size: 1rem;
}

.login-container button {
    width: 100%;
    padding: 12px;
    background: #00d4ff;
    color: #1a1a2e;
    border: none;
    border-radius: 8px;
    font-weight: 700;
    cursor: pointer;
    transition: background 0.3s;
}

.login-container button:hover {
    background: #00b8d4;
}

.error {
    color: #e74c3c;
    margin-bottom: 10px;
}

/* 管理后台仪表盘 */
.dashboard {
    padding: 60px 20px;
    background: #f4f7fc;
    min-height: 60vh;
}

.dashboard h2 {
    text-align: center;
    margin-bottom: 40px;
    color: #1a1a2e;
}

.dashboard-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 30px;
}

.dashboard-cards .card {
    background: #fff;
    border-radius: 16px;
    padding: 30px;
    text-align: center;
    box-shadow: 0 8px 20px rgba(0,0,0,0.05);
    transition: transform 0.3s;
}

.dashboard-cards .card:hover {
    transform: translateY(-5px);
}

.dashboard-cards .card i {
    font-size: 2.5rem;
    color: #00d4ff;
    margin-bottom: 15px;
}

.dashboard-cards .card h3 {
    margin-bottom: 10px;
}

/* 内页通用样式 */
.page-content {
    padding: 60px 20px;
    background: #fff;
    min-height: 60vh;
}

.page-content h1 {
    text-align: center;
    margin-bottom: 30px;
    color: #1a1a2e;
}

.page-content p {
    max-width: 800px;
    margin: 0 auto 20px;
    text-align: center;
    font-size: 1.1rem;
    color: #555;
}

/* 响应式 */
@media (max-width: 768px) {
    .nav-links {
        display: none;
        flex-direction: column;
        background: #1a1a2e;
        position: absolute;
        top: 70px;
        left: 0;
        width: 100%;
        padding: 20px;
        box-shadow: 0 10px 20px rgba(0,0,0,0.3);
    }
    .nav-links.active {
        display: flex;
    }
    .hamburger {
        display: block;
    }
    .hero h1 {
        font-size: 1.8rem;
    }
    .stats {
        flex-direction: column;
        gap: 20px;
        text-align: center;
    }
}