* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    user-select: none;
}

body {
    font-family: 'Segoe UI', 'Poppins', 'Microsoft YaHei', sans-serif;
    overflow-x: hidden;
    background: #0a0f1e;
}

.bg-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -2;
}

.bg-img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    filter: brightness(0.85);
}

.main-content {
    position: relative;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: flex-start;
    backdrop-filter: blur(3px);
    padding: 0;
}

/* 标题区域 - 固定在屏幕最顶部，完全贴边 */
.title-section {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    text-align: center;
    padding: 0 20px 0 20px;
    background: rgba(0, 0, 0, 0.3);
    backdrop-filter: blur(10px);
    z-index: 50;
}

/* TD导航页标题 - 彩色渐变，不是黑色 */
.main-title {
    font-size: 3rem;
    font-weight: 800;
    background: linear-gradient(135deg, #FFD700, #FFA500, #FF6B6B, #FF8C00);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    text-shadow: none;
    letter-spacing: 4px;
    margin: 10px 0 5px 0;
    line-height: 1.2;
}

.btn-guanwang {
    display: inline-block;
    margin-top: 0;
    margin-bottom: 10px;
    padding: 6px 20px;
    background: rgba(255,255,255,0.2);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255,255,255,0.5);
    border-radius: 40px;
    color: white;
    text-decoration: none;
    font-weight: 500;
    font-size: 0.9rem;
    transition: 0.3s;
}

.btn-guanwang:hover {
    background: rgba(255,255,255,0.4);
    transform: scale(1.02);
}

.buttons-area {
    max-width: 900px;
    width: 100%;
    margin: 100px auto 40px auto;
    display: flex;
    flex-direction: column;
    gap: 25px;
    align-items: center;
}

.row-top {
    display: flex;
    justify-content: center;
    gap: 40px;
    flex-wrap: wrap;
}

.row-bottom {
    display: flex;
    justify-content: center;
    gap: 40px;
    flex-wrap: wrap;
    margin-top: 5px;
}

.big-btn {
    width: 180px;
    height: 180px;
    background: rgba(30,30,50,0.75);
    backdrop-filter: blur(12px);
    border-radius: 35px;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    text-decoration: none;
    color: white;
    font-size: 1.8rem;
    font-weight: bold;
    transition: all 0.3s cubic-bezier(0.2, 0.9, 0.4, 1.1);
    border: 1px solid rgba(255,255,255,0.3);
    box-shadow: 0 15px 35px rgba(0,0,0,0.3);
}

.big-btn:hover {
    transform: translateY(-8px);
    background: rgba(50,50,80,0.85);
    border-color: rgba(255,215,0,0.6);
    box-shadow: 0 25px 40px rgba(0,0,0,0.4);
}

.expand-arrow {
    position: fixed;
    left: 30px;
    bottom: 30px;
    background: rgba(0,0,0,0.6);
    backdrop-filter: blur(8px);
    width: 60px;
    height: 60px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    z-index: 100;
    transition: 0.3s;
    border: 1px solid rgba(255,255,255,0.4);
    color: white;
    font-size: 32px;
}

.expand-arrow:hover {
    background: rgba(0,0,0,0.9);
    transform: scale(1.05);
}

.music-sidebar {
    position: fixed;
    top: 0;
    right: -100%;
    width: 100%;
    max-width: 650px;
    height: 100vh;
    background: rgba(20,20,35,0.95);
    backdrop-filter: blur(20px);
    z-index: 200;
    transition: right 0.5s ease;
    box-shadow: -5px 0 30px rgba(0,0,0,0.5);
    border-left: 1px solid rgba(255,255,255,0.2);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.music-sidebar.active {
    right: 0;
}

.music-player {
    width: 80%;
    text-align: center;
    padding: 30px;
}

.song-name-display {
    font-size: 2.8rem;
    font-weight: bold;
    color: #ffecb3;
    margin-bottom: 50px;
    text-shadow: 0 2px 10px rgba(0,0,0,0.5);
    word-break: break-word;
}

.controls {
    display: flex;
    justify-content: center;
    gap: 40px;
    margin-top: 20px;
}

.ctrl-btn {
    background: rgba(255,255,255,0.15);
    border: none;
    width: 70px;
    height: 70px;
    border-radius: 50%;
    font-size: 32px;
    color: white;
    cursor: pointer;
    transition: 0.2s;
    backdrop-filter: blur(4px);
}

.ctrl-btn:hover {
    background: rgba(255,255,255,0.4);
    transform: scale(1.05);
}

.collapse-arrow {
    position: absolute;
    right: 30px;
    top: 30px;
    font-size: 40px;
    color: white;
    cursor: pointer;
    background: rgba(0,0,0,0.5);
    width: 55px;
    height: 55px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: 0.2s;
}

.collapse-arrow:hover {
    background: rgba(0,0,0,0.8);
}

@media (max-width: 768px) {
    .main-title {
        font-size: 2rem;
    }
    .buttons-area {
        margin: 85px auto 30px auto;
    }
    .big-btn {
        width: 130px;
        height: 130px;
        font-size: 1.3rem;
    }
    .row-top {
        gap: 20px;
    }
    .row-bottom {
        gap: 20px;
    }
}

@media (max-width: 480px) {
    .main-title {
        font-size: 1.5rem;
    }
    .buttons-area {
        margin: 75px auto 20px auto;
    }
    .big-btn {
        width: 100px;
        height: 100px;
        font-size: 1rem;
    }
    .row-top {
        gap: 12px;
    }
    .row-bottom {
        gap: 12px;
    }
}