body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #f4f4f9;
    color: #333;
    margin: 0;
    padding: 20px;
}

header {
    background-color: #2c3e50;
    color: #ecf0f1;
    padding: 20px;
    text-align: center;
    border-radius: 8px;
    margin-bottom: 20px;
}

nav {
    margin-bottom: 20px;
    text-align: center;
}

nav a {
    margin: 0 15px;
    text-decoration: none;
    color: #3498db;
    font-weight: bold;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    background: white;
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.upload-section, .library-section, .settings-section, .result-section {
    margin-bottom: 40px;
    border-bottom: 1px solid #eee;
    padding-bottom: 20px;
}

h2 {
    color: #2c3e50;
    border-left: 5px solid #3498db;
    padding-left: 10px;
}

.song-card {
    background: #f9f9f9;
    border: 1px solid #ddd;
    padding: 15px;
    margin-bottom: 10px;
    border-radius: 5px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.song-info span {
    margin-right: 15px;
    font-size: 0.9em;
    color: #666;
}

.btn {
    background-color: #3498db;
    color: white;
    padding: 10px 20px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1em;
}

.btn:hover {
    background-color: #2980b9;
}

.btn-generate {
    background-color: #27ae60;
    display: block;
    width: 100%;
    margin-top: 20px;
    font-size: 1.2em;
}

.btn-generate:hover {
    background-color: #219150;
}

.settings-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
}

.setting-item {
    display: flex;
    flex-direction: column;
}

.setting-item label {
    font-weight: bold;
    margin-bottom: 5px;
}

.setting-item input[type="text"], .setting-item input[type="number"], .setting-item select {
    padding: 8px;
    border: 1px solid #ccc;
    border-radius: 4px;
}

.setting-item-row {
    flex-direction: row;
    align-items: center;
}

.setting-item-row input {
    margin-right: 10px;
}

.loading {
    display: none;
    text-align: center;
    margin: 20px 0;
}

#selectionList {
    max-height: 400px;
    overflow-y: auto;
    border: 1px solid #ddd;
    border-radius: 8px;
    padding: 10px;
    background: #fafafa;
}

.audio-player {
    width: 100%;
    margin-top: 15px;
}