/* 基础样式 */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Noto Sans SC', sans-serif;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    padding: 20px;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 30px;
    border-radius: 20px;
    flex: 1;
    background: var(--container-bg);
    box-shadow: 0 15px 35px var(--shadow);
    animation: fadeIn 0.5s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 50px;
    padding-bottom: 20px;
    border-bottom: 2px solid var(--border);
}

.logo {
    display: flex;
    align-items: center;
    gap: 15px;
}

.logo i {
    font-size: 2.5em;
    color: var(--primary-color);
}

h1 {
    font-size: 2.5em;
    color: var(--text);
    margin: 0;
    background: linear-gradient(120deg, var(--primary-color), var(--primary-hover));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.nav-buttons {
    display: flex;
    gap: 15px;
    align-items: center;
}

.btn {
    padding: 12px 25px;
    border-radius: 12px;
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s;
    display: flex;
    align-items: center;
    gap: 8px;
}

.primary {
    background: var(--primary-color);
    color: white;
}

.primary:hover {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 5px 15px var(--primary-shadow);
}

.content {
    padding: 20px 0;
    text-align: center;
}

h2 {
    font-size: 2.2em;
    margin-bottom: 20px;
    color: var(--text);
}

.subtitle {
    font-size: 1.2em;
    line-height: 1.6;
    margin-bottom: 50px;
    color: var(--text-secondary);
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

.feature-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    margin-top: 40px;
}

.feature-item {
    padding: 30px;
    border-radius: 16px;
    background: var(--feature-bg);
    box-shadow: 0 10px 20px var(--shadow);
    transition: all 0.3s;
    position: relative;
    overflow: hidden;
}

.feature-item::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--primary-color), var(--primary-hover));
    opacity: 0;
    transition: all 0.3s;
}

.feature-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 30px var(--shadow);
}

.feature-item:hover::before {
    opacity: 1;
}

.feature-item i {
    font-size: 2.5em;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.feature-item h3 {
    font-size: 1.4em;
    margin-bottom: 15px;
    color: var(--text);
}

.feature-item p {
    font-size: 1em;
    margin-bottom: 0;
    color: var(--text-secondary);
}

/* 主题切换按钮 */
.theme-switch {
    width: 45px;
    height: 45px;
    border-radius: 50%;
    background: var(--container-bg);
    box-shadow: 0 5px 15px var(--shadow);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.3s;
    margin-left: 15px;
}

.theme-switch:hover {
    transform: scale(1.1);
}

.theme-switch i {
    font-size: 1.2em;
    color: var(--text);
}

@media (max-width: 768px) {
    .container {
        padding: 20px;
    }
    
    .header {
        flex-direction: column;
        text-align: center;
        gap: 20px;
    }
    
    .logo {
        justify-content: center;
    }
    
    .nav-buttons {
        width: 100%;
        justify-content: center;
    }
    
    h1 {
        font-size: 2em;
    }
    
    h2 {
        font-size: 1.8em;
    }
    
    .subtitle {
        font-size: 1.1em;
    }
}