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

:root {
    --primary-color: #007AFF;
    --secondary-color: #5AC8FA;
    --danger-color: #FF3B30;
    --success-color: #34C759;
    --warning-color: #FF9500;
    --dark-bg: #1C1C1E;
    --card-bg: #2C2C2E;
    --text-primary: #FFFFFF;
    --text-secondary: #A1A1A6;
    --border-color: #3A3A3C;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: linear-gradient(135deg, var(--dark-bg) 0%, #0A0A0A 100%);
    color: var(--text-primary);
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 500px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

header {
    text-align: center;
    margin-bottom: 30px;
    padding-top: 20px;
}

header h1 {
    font-size: 32px;
    margin-bottom: 8px;
    background: linear-gradient(135deg, var(--secondary-color), var(--primary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 14px;
}

main {
    flex: 1;
}

.section {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 20px;
    margin-bottom: 20px;
    border: 1px solid var(--border-color);
}

.section h2 {
    font-size: 18px;
    margin-bottom: 16px;
    color: var(--text-primary);
}

/* Form Styles */
.form-group {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.input-field {
    padding: 12px 16px;
    background: var(--dark-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-primary);
    font-size: 16px;
    transition: border-color 0.3s;
}

.input-field:focus {
    outline: none;
    border-color: var(--primary-color);
}

.input-field::placeholder {
    color: var(--text-secondary);
}

/* Button Styles */
.btn {
    padding: 12px 20px;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
}

.btn-primary:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 8px 16px rgba(0, 122, 255, 0.3);
}

.btn-play {
    background: linear-gradient(135deg, var(--success-color), #30B0C0);
    color: white;
    flex: 1;
}

.btn-play:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 8px 16px rgba(52, 199, 89, 0.3);
}

.btn-toggle {
    width: 96px;
    height: 96px;
    border-radius: 50%;
    border: 1px solid var(--border-color);
    background: var(--dark-bg);
    color: var(--text-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    flex: 0 0 auto;
    padding: 0;
}

.btn-toggle:hover:not(:disabled) {
    transform: translateY(-1px);
}

.control-icon-svg {
    width: 42px;
    height: 42px;
    fill: currentColor;
}

.btn-toggle .icon-pause {
    display: none;
}

.btn-toggle.is-playing .icon-play {
    display: none;
}

.btn-toggle.is-playing .icon-pause {
    display: inline;
}

.btn-pause {
    background: linear-gradient(135deg, var(--warning-color), #FFAD33);
    color: white;
    flex: 1;
}

.btn-pause:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 8px 16px rgba(255, 149, 0, 0.3);
}

.btn-small {
    padding: 8px 12px;
    font-size: 12px;
    border-radius: 6px;
}

.btn-delete {
    background: var(--danger-color);
    color: white;
}

.btn-delete:hover:not(:disabled) {
    background: #E63129;
}

/* Songs List */
.songs-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.song-item {
    background: var(--dark-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 14px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    transition: all 0.3s;
}

.song-item:hover {
    border-color: var(--primary-color);
    background: rgba(0, 122, 255, 0.1);
}

.song-item.active {
    background: rgba(0, 122, 255, 0.2);
    border-color: var(--primary-color);
}

.song-item.dragging {
    opacity: 0.5;
}

.song-item.drag-over {
    border-color: var(--secondary-color);
    box-shadow: 0 0 0 2px rgba(90, 200, 250, 0.35);
}

.song-info {
    flex: 1;
}

.song-name {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 4px;
}

.song-bpm {
    font-size: 13px;
    color: var(--text-secondary);
}

.song-actions {
    display: flex;
    gap: 8px;
    margin-left: 12px;
}

.empty-state {
    text-align: center;
    color: var(--text-secondary);
    padding: 20px;
    font-style: italic;
}

/* Player Section */
.player-section {
    background: linear-gradient(135deg, rgba(0, 122, 255, 0.1), rgba(90, 200, 250, 0.1));
    border: 2px solid var(--primary-color);
}

.player-display {
    background: var(--dark-bg);
    border-radius: 12px;
    padding: 24px;
    margin-bottom: 20px;
    text-align: center;
    border: 1px solid var(--border-color);
}

.current-song {
    margin-bottom: 20px;
}

.song-name {
    font-size: 22px;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.bpm-display {
    display: flex;
    align-items: baseline;
    justify-content: center;
    gap: 8px;
}

.bpm-value {
    font-size: 48px;
    font-weight: 800;
    background: linear-gradient(135deg, var(--secondary-color), var(--primary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.bpm-label {
    font-size: 14px;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.beat-indicator {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    background: var(--border-color);
    margin: 0 auto;
    transition: all 0.1s;
}

.beat-indicator.beat {
    background: var(--success-color);
    box-shadow: 0 0 20px rgba(52, 199, 89, 0.6);
    transform: scale(1.1);
}

/* Player Controls */
.player-controls {
    display: flex;
    gap: 10px;
    justify-content: center;
    margin-bottom: 20px;
}

/* Tempo Adjustment */
.tempo-adjustment {
    background: var(--dark-bg);
    padding: 16px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.tempo-adjustment label {
    display: block;
    font-size: 13px;
    color: var(--text-secondary);
    margin-bottom: 12px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.slider {
    width: 100%;
    height: 6px;
    border-radius: 3px;
    background: var(--border-color);
    outline: none;
    -webkit-appearance: none;
    appearance: none;
    margin-bottom: 12px;
}

.slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--primary-color);
    cursor: pointer;
    transition: all 0.3s;
}

.slider::-webkit-slider-thumb:hover {
    box-shadow: 0 0 12px rgba(0, 122, 255, 0.6);
    transform: scale(1.2);
}

.slider::-moz-range-thumb {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--primary-color);
    cursor: pointer;
    border: none;
    transition: all 0.3s;
}

.slider::-moz-range-thumb:hover {
    box-shadow: 0 0 12px rgba(0, 122, 255, 0.6);
    transform: scale(1.2);
}

#sliderValue {
    font-size: 14px;
    font-weight: 600;
    color: var(--primary-color);
}

/* Tap Tempo Section */
.tap-tempo-section {
    background: var(--dark-bg);
    padding: 20px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    margin-top: 12px;
    text-align: center;
}

.btn-tap {
    width: 100%;
    background: linear-gradient(135deg, var(--secondary-color), var(--primary-color));
    color: white;
    font-size: 18px;
    padding: 16px;
}

.btn-tap:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 8px 16px rgba(90, 200, 250, 0.3);
}

.btn-tap.tap-active {
    transform: scale(0.95);
    box-shadow: 0 0 20px rgba(90, 200, 250, 0.6);
}

.tap-hint {
    font-size: 12px;
    color: var(--text-secondary);
    margin-top: 12px;
    font-style: italic;
}

/* Footer */
footer {
    text-align: center;
    color: var(--text-secondary);
    padding: 20px 0;
    font-size: 13px;
    margin-top: 20px;
}

/* Responsive Design */
@media (max-width: 480px) {
    .container {
        padding: 0;
    }

    header h1 {
        font-size: 28px;
    }

    .section {
        border-radius: 0;
        margin-bottom: 0;
        border-left: none;
        border-right: none;
        border-bottom: 1px solid var(--border-color);
    }

    .bpm-value {
        font-size: 36px;
    }
}