/* 基础重置和变量 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* 颜色变量 - 基于DESIGN.md */
    --background-base: #121212;
    --background-surface: #181818;
    --background-elevated: #1f1f1f;
    --text-base: #ffffff;
    --text-subdued: #b3b3b3;
    --text-bright: #cbcbcb;
    --text-light: #fdfdfd;
    --accent-green: #1ed760;
    --negative-red: #f3727f;
    --warning-orange: #ffa42b;
    --announcement-blue: #539df5;
    --card-dark: #252525;
    --card-mid: #272727;
    --border-gray: #4d4d4d;
    --border-light: #7c7c7c;
    --separator: #b3b3b3;
    --light-surface: #eeeeee;
    
    /* 字体变量 */
    --font-family-title: 'SpotifyMixUITitle', 'CircularSp-Arab', 'CircularSp-Hebr', 'CircularSp-Cyrl', 'CircularSp-Grek', 'CircularSp-Deva', 'Helvetica Neue', helvetica, arial, 'Hiragino Sans', 'Hiragino Kaku Gothic ProN', 'Meiryo', 'MS Gothic', sans-serif;
    --font-family-ui: 'SpotifyMixUI', 'CircularSp-Arab', 'CircularSp-Hebr', 'CircularSp-Cyrl', 'CircularSp-Grek', 'CircularSp-Deva', 'Helvetica Neue', helvetica, arial, 'Hiragino Sans', 'Hiragino Kaku Gothic ProN', 'Meiryo', 'MS Gothic', sans-serif;
    
    /* 间距变量 */
    --spacing-base: 8px;
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;
    
    /* 圆角变量 */
    --radius-minimal: 2px;
    --radius-subtle: 4px;
    --radius-standard: 6px;
    --radius-comfortable: 8px;
    --radius-medium: 10px;
    --radius-large: 100px;
    --radius-pill: 500px;
    --radius-full: 9999px;
    --radius-circle: 50%;
}

/* 基础样式 */
body {
    font-family: var(--font-family-ui);
    background-color: var(--background-base);
    color: var(--text-base);
    line-height: 1.5;
    overflow-x: hidden;
}

.app {
    display: flex;
    height: 100vh;
    background-color: var(--background-base);
}

/* 侧边栏 */
.sidebar {
    width: 240px;
    background-color: var(--background-base);
    padding: var(--spacing-md);
    display: flex;
    flex-direction: column;
    position: fixed;
    height: 100vh;
    left: 0;
    top: 0;
    z-index: 100;
}

.sidebar-header {
    margin-bottom: var(--spacing-xl);
}

.logo {
    font-size: 24px;
    font-weight: 700;
    color: var(--text-base);
    text-align: center;
    padding: var(--spacing-md) 0;
}

.sidebar-nav {
    margin-bottom: var(--spacing-xl);
}

.sidebar-nav ul {
    list-style: none;
}

.sidebar-nav li {
    margin-bottom: var(--spacing-sm);
}

.nav-link {
    display: block;
    padding: var(--spacing-sm) var(--spacing-md);
    color: var(--text-subdued);
    text-decoration: none;
    font-size: 14px;
    font-weight: 400;
    border-radius: var(--radius-pill);
    transition: all 0.2s ease;
}

.nav-link:hover {
    color: var(--text-base);
    background-color: var(--background-elevated);
}

.nav-link.active {
    color: var(--text-base);
    font-weight: 700;
    background-color: var(--background-elevated);
}

.sidebar-playlists h3 {
    font-size: 12px;
    font-weight: 700;
    color: var(--text-subdued);
    text-transform: uppercase;
    letter-spacing: 1.4px;
    margin-bottom: var(--spacing-md);
}

.playlist-link {
    display: block;
    padding: var(--spacing-xs) var(--spacing-md);
    color: var(--text-subdued);
    text-decoration: none;
    font-size: 14px;
    font-weight: 400;
    border-radius: var(--radius-pill);
    transition: all 0.2s ease;
}

.playlist-link:hover {
    color: var(--text-base);
    background-color: var(--background-elevated);
}

/* 主内容区 */
.main-content {
    flex: 1;
    margin-left: 240px;
    padding: var(--spacing-lg);
    background-color: var(--background-base);
    overflow-y: auto;
    height: calc(100vh - 90px);
}

.content-header {
    margin-bottom: var(--spacing-xl);
}

.search-container {
    position: relative;
    max-width: 400px;
}

.search-input {
    width: 100%;
    padding: 12px 48px;
    background-color: var(--background-elevated);
    color: var(--text-base);
    border: none;
    border-radius: var(--radius-pill);
    font-size: 14px;
    font-family: var(--font-family-ui);
    box-shadow: rgb(18,18,18) 0px 1px 0px, rgb(124,124,124) 0px 0px 0px 1px inset;
    transition: all 0.2s ease;
}

.search-input:focus {
    outline: none;
    box-shadow: 0 0 0 1px var(--text-base);
}

.search-input::placeholder {
    color: var(--text-subdued);
}

.search-icon {
    position: absolute;
    left: 16px;
    top: 50%;
    transform: translateY(-50%);
    width: 16px;
    height: 16px;
    color: var(--text-subdued);
}

/* 内容区域 */
.section {
    margin-bottom: var(--spacing-xl);
}

.section-title {
    font-family: var(--font-family-title);
    font-size: 24px;
    font-weight: 700;
    color: var(--text-base);
    margin-bottom: var(--spacing-lg);
}

.songs-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: var(--spacing-lg);
}

.song-card {
    background-color: var(--background-surface);
    border-radius: var(--radius-comfortable);
    padding: var(--spacing-md);
    cursor: pointer;
    transition: all 0.2s ease;
    position: relative;
    overflow: hidden;
}

.song-card:hover {
    background-color: var(--background-elevated);
    box-shadow: rgba(0,0,0,0.3) 0px 8px 8px;
}

.song-card:hover .play-button {
    opacity: 1;
}

.album-art-container {
    position: relative;
    margin-bottom: var(--spacing-md);
}

.album-art {
    width: 100%;
    height: 200px;
    background: linear-gradient(135deg, var(--background-elevated), var(--card-dark));
    border-radius: var(--radius-standard);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 48px;
    color: var(--text-subdued);
}

.play-button {
    position: absolute;
    bottom: 8px;
    right: 8px;
    width: 48px;
    height: 48px;
    background-color: var(--accent-green);
    border-radius: var(--radius-circle);
    border: none;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    opacity: 0;
    transition: all 0.2s ease;
    box-shadow: rgba(0,0,0,0.5) 0px 8px 24px;
}

.play-button:hover {
    transform: scale(1.05);
}

.play-button svg {
    width: 20px;
    height: 20px;
    color: #000000;
    margin-left: 2px;
}

.song-title {
    font-size: 16px;
    font-weight: 700;
    color: var(--text-base);
    margin-bottom: var(--spacing-xs);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.song-artist {
    font-size: 14px;
    color: var(--text-subdued);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

/* 底部播放栏 */
.now-playing-bar {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    height: 90px;
    background-color: var(--background-base);
    border-top: 1px solid var(--border-gray);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 var(--spacing-lg);
    z-index: 200;
}

.now-playing {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    flex: 1;
}

.album-art-placeholder {
    width: 56px;
    height: 56px;
    background: linear-gradient(135deg, var(--background-elevated), var(--card-dark));
    border-radius: var(--radius-standard);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    color: var(--text-subdued);
}

.track-info {
    min-width: 180px;
}

.track-name {
    font-size: 14px;
    font-weight: 400;
    color: var(--text-base);
    margin-bottom: var(--spacing-xs);
}

.artist-name {
    font-size: 12px;
    color: var(--text-subdued);
}

.player-controls {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-sm);
    flex: 1;
    max-width: 722px;
}

.controls-buttons {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.control-btn {
    background: none;
    border: none;
    color: var(--text-subdued);
    cursor: pointer;
    padding: var(--spacing-sm);
    border-radius: var(--radius-circle);
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.control-btn:hover {
    color: var(--text-base);
    background-color: var(--background-elevated);
}

.control-btn svg {
    width: 16px;
    height: 16px;
}

.play-btn {
    background-color: var(--text-base);
    border: none;
    border-radius: var(--radius-circle);
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.2s ease;
}

.play-btn:hover {
    transform: scale(1.05);
}

.play-btn svg {
    width: 16px;
    height: 16px;
    color: var(--background-base);
}

.progress-container {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    width: 100%;
}

.time {
    font-size: 12px;
    color: var(--text-subdued);
    min-width: 40px;
    text-align: center;
}

.progress-bar {
    flex: 1;
    height: 4px;
    background-color: var(--background-elevated);
    border-radius: 2px;
    position: relative;
    cursor: pointer;
}

.progress {
    height: 100%;
    background-color: var(--text-subdued);
    border-radius: 2px;
    width: 0%;
    transition: width 0.1s ease;
}

.progress-bar:hover .progress {
    background-color: var(--accent-green);
}

.volume-controls {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    flex: 1;
    justify-content: flex-end;
}

.volume-slider {
    width: 93px;
}

.volume-range {
    width: 100%;
    height: 4px;
    background-color: var(--background-elevated);
    border-radius: 2px;
    outline: none;
    -webkit-appearance: none;
    appearance: none;
    cursor: pointer;
}

.volume-range::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 12px;
    height: 12px;
    background-color: var(--text-base);
    border-radius: 50%;
    cursor: pointer;
}

.volume-range::-moz-range-thumb {
    width: 12px;
    height: 12px;
    background-color: var(--text-base);
    border-radius: 50%;
    cursor: pointer;
    border: none;
}

/* 按钮样式 */
.pill-button {
    background-color: var(--background-elevated);
    color: var(--text-base);
    border: none;
    border-radius: var(--radius-full);
    padding: 8px 16px;
    font-size: 14px;
    font-weight: 700;
    font-family: var(--font-family-ui);
    text-transform: uppercase;
    letter-spacing: 1.4px;
    cursor: pointer;
    transition: all 0.2s ease;
}

.pill-button:hover {
    background-color: var(--card-dark);
    transform: scale(1.02);
}

.primary-button {
    background-color: var(--accent-green);
    color: #000000;
}

.primary-button:hover {
    background-color: #1fdf64;
}

.outlined-button {
    background-color: transparent;
    color: var(--text-base);
    border: 1px solid var(--border-light);
}

.outlined-button:hover {
    border-color: var(--text-base);
}

/* 滚动条样式 */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--background-base);
}

::-webkit-scrollbar-thumb {
    background: var(--border-gray);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--border-light);
}

/* 响应式设计 */
@media (max-width: 1024px) {
    .sidebar {
        width: 200px;
    }
    
    .main-content {
        margin-left: 200px;
    }
    
    .songs-grid {
        grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    }
}

@media (max-width: 768px) {
    .sidebar {
        width: 72px;
        padding: var(--spacing-sm);
    }
    
    .sidebar span, .sidebar h3, .sidebar-playlists {
        display: none;
    }
    
    .logo {
        justify-content: center;
    }
    
    .main-content {
        margin-left: 72px;
        padding: var(--spacing-md);
    }
    
    .songs-grid {
        grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
        gap: var(--spacing-md);
    }
    
    .now-playing-bar {
        padding: 0 var(--spacing-md);
    }
    
    .track-info {
        min-width: 120px;
    }
    
    .volume-controls {
        display: none;
    }
}

@media (max-width: 480px) {
    .sidebar {
        display: none;
    }
    
    .main-content {
        margin-left: 0;
    }
    
    .songs-grid {
        grid-template-columns: 1fr;
    }
    
    .now-playing-bar {
        flex-direction: column;
        height: auto;
        padding: var(--spacing-md);
        gap: var(--spacing-md);
    }
    
    .player-controls {
        width: 100%;
    }
}