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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: #fafafa;
    min-height: 100vh;
    padding: 20px;
    background-image: url('../images/nav_bg.jpg');
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
    background-blend-mode: overlay;
}

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

header {
    text-align: center;
    padding: 60px 20px;
}

header h1 {
    font-size: 3em;
    margin-bottom: 15px;
    font-weight: 700;
    letter-spacing: 2px;
    background: linear-gradient(135deg, #00b894 0%, #55efc4 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

header p {
    font-size: 1.3em;
    opacity: 0.8;
    font-weight: 300;
    letter-spacing: 1px;
    color: #5a6c7d;
}

.search-box {
    background: #ffffff;
    border-radius: 60px;
    padding: 8px;
    display: flex;
    max-width: 750px;
    margin: 40px auto;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    border: 1px solid #e8e8e8;
}

.search-box input {
    flex: 1;
    border: none;
    padding: 18px 30px;
    font-size: 17px;
    border-radius: 50px;
    outline: none;
    background: transparent;
    color: #2d3436;
    font-weight: 500;
    transition: all 0.3s ease;
}

.search-box input::placeholder {
    color: #95a5a6;
    font-weight: 400;
}

.search-box input:focus {
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.15);
    border-radius: 50px;
}

.search-box button {
    background: #3498db;
    color: white;
    border: none;
    padding: 16px 45px;
    border-radius: 50px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    letter-spacing: 1px;
    box-shadow: 0 4px 15px rgba(52, 152, 219, 0.3);
}

.search-box button:hover {
    transform: translateY(-2px);
    background: #2980b9;
    box-shadow: 0 6px 20px rgba(52, 152, 219, 0.35);
}

.search-box button:active {
    transform: translateY(-1px) scale(0.98);
    box-shadow: 0 2px 10px rgba(52, 152, 219, 0.25);
}

.nav-section {
    background: #ffffff;
    border-radius: 10px;
    margin-bottom: 30px;
    overflow: hidden;
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.06);
    transition: all 0.3s ease;
    border: 1px solid #eee;
}

.nav-section:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 45%);
}

.section-header {
    background: #ffffff;
    color: #2c3e50;
    padding: 20px 30px;
    font-size: 1.3em;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 12px;
    letter-spacing: 1px;
    border-bottom: 2px solid #3498db;
}

.section-header .icon {
    font-size: 1.5em;
}

.section-content {
    padding: 25px;
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 18px;
    background: #fafafa;
}

.nav-item {
    display: flex;
    align-items: center;
    gap: 14px;
    padding: 14px 18px;
    background: #ffffff;
    border-radius: 10px;
    text-decoration: none;
    color: #2c3e50;
    transition: all 0.25s ease;
    border: 1px solid #eee;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.04);
}

.nav-item:hover {
    border-color: #3498db;
    transform: translateY(-3px);
    box-shadow: 0 6px 20px rgba(52, 152, 219, 0.12);
    color: #3498db;
}

.nav-item:hover .desc {
    color: #3498db;
}

.nav-item .icon {
    font-size: 1.6em;
    width: 42px;
    height: 42px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 10px;
    transition: transform 0.25s ease;
    background: #f5f5f5;
}

.nav-item:hover .icon {
    transform: scale(1.08);
}

.nav-item .text {
    font-size: 1em;
    font-weight: 600;
    letter-spacing: 0.5px;
}

.nav-item .desc {
    font-size: 0.8em;
    color: #636e72;
    margin-top: 3px;
    transition: color 0.3s ease;
}

.baidu {
    background: #fff2cc;
}

.google {
    background: #f5f5f5;
}

.bing {
    background: #0078d4;
    color: white;
}

.github {
    background: #24292e;
    color: white;
}

.jd {
    background: #ff0000;
    color: white;
}

.taobao {
    background: #ff6700;
    color: white;
}

.bilibili {
    background: #00a1d6;
    color: white;
}

.music {
    background: #e6002d;
    color: white;
}

.footer {
    text-align: center;
    padding: 40px;
    color: #7f8c8d;
    font-size: 0.95em;
    letter-spacing: 1px;
}

.footer a {
    color: #3498db;
    text-decoration: none;
    transition: all 0.3s ease;
    font-weight: 500;
}

.footer a:hover {
    color: #2980b9;
    text-decoration: underline;
}

.game-grid {
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
}

.game-item {
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
    padding: 18px;
}

.game-item .icon {
    font-size: 2.2em;
}

@media (max-width: 768px) {
    header {
        padding: 40px 15px;
    }

    header h1 {
        font-size: 2.2em;
        letter-spacing: 1px;
    }

    header p {
        font-size: 1.1em;
    }

    .search-box {
        flex-direction: column;
        border-radius: 20px;
        padding: 15px;
    }

    .search-box input {
        border-radius: 14px;
        margin-bottom: 12px;
        padding: 15px 20px;
    }

    .search-box button {
        border-radius: 14px;
        padding: 15px;
    }

    .section-content {
        grid-template-columns: repeat(2, 1fr);
        gap: 12px;
        padding: 15px;
    }

    .nav-item {
        flex-direction: column;
        text-align: center;
        gap: 8px;
        padding: 12px;
    }

    .nav-item .icon {
        width: 36px;
        height: 36px;
        font-size: 1.4em;
    }

    .game-grid {
        grid-template-columns: 1fr;
    }

    .nav-section {
        margin-bottom: 20px;
        border-radius: 16px;
    }

    .section-header {
        padding: 15px 20px;
        font-size: 1.1em;
    }

    .sidebar-nav {
        display: none;
    }
}

.sidebar-nav {
    position: fixed;
    left: 20px;
    top: 50%;
    transform: translateY(-50%);
    background: #ffffff;
    border-radius: 12px;
    padding: 10px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    z-index: 1000;
    max-height: 90vh;
    overflow-y: auto;
    scrollbar-width: thin;
    border: 1px solid #eee;
}

.sidebar-nav::-webkit-scrollbar {
    width: 4px;
}

.sidebar-nav::-webkit-scrollbar-thumb {
    background: #ddd;
    border-radius: 4px;
}

.sidebar-nav-item {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 14px;
    border-radius: 8px;
    text-decoration: none;
    color: #2c3e50;
    font-size: 0.85em;
    font-weight: 500;
    transition: all 0.25s ease;
    cursor: pointer;
    white-space: nowrap;
}

.sidebar-nav-item:hover {
    background: #f0f7fc;
    color: #3498db;
}

.sidebar-nav-item.active {
    background: #ebf5fb;
    color: #3498db;
}