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

:root {
    --primary-color: #4285f4;
    --secondary-color: #34a853;
    --accent-color: #ea4335;
    --dark-bg: #202124;
    --light-bg: #303134;
    --surface-bg: #3c4043;
    --text-primary: #e8eaed;
    --text-secondary: #9aa0a6;
    --border-color: #5f6368;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.12), 0 1px 2px rgba(0, 0, 0, 0.24);
    --shadow-hover: 0 4px 6px rgba(0, 0, 0, 0.16), 0 1px 3px rgba(0, 0, 0, 0.23);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--dark-bg);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

header {
    text-align: center;
    padding: 40px 0;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

h1 {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 10px;
    letter-spacing: -1px;
}

.subtitle {
    font-size: 1.2rem;
    color: var(--text-secondary);
    -webkit-text-fill-color: var(--text-secondary);
}

main {
    display: grid;
    gap: 30px;
}

.config-panel {
    background: var(--light-bg);
    border-radius: 12px;
    padding: 30px;
    box-shadow: var(--shadow);
}

.config-panel h2 {
    font-size: 1.5rem;
    margin-bottom: 20px;
    color: var(--primary-color);
}

.config-group {
    margin-bottom: 25px;
}

.config-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--text-secondary);
}

select, input[type="range"] {
    width: 100%;
    padding: 10px;
    background: var(--surface-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-primary);
    font-size: 16px;
    transition: all 0.3s ease;
}

select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(66, 133, 244, 0.1);
}

input[type="range"] {
    padding: 5px 0;
    -webkit-appearance: none;
    appearance: none;
}

input[type="range"]::-webkit-slider-track {
    width: 100%;
    height: 6px;
    background: var(--border-color);
    border-radius: 3px;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 18px;
    height: 18px;
    background: var(--primary-color);
    border-radius: 50%;
    cursor: pointer;
    transition: all 0.3s ease;
}

input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.2);
    box-shadow: 0 0 0 8px rgba(66, 133, 244, 0.1);
}

.checkbox-group {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 15px;
}

.checkbox {
    display: flex;
    align-items: center;
    cursor: pointer;
    transition: all 0.3s ease;
}

.checkbox input[type="checkbox"] {
    width: 20px;
    height: 20px;
    margin-right: 10px;
    cursor: pointer;
    accent-color: var(--primary-color);
}

.checkbox span {
    font-size: 0.95rem;
}

.control-panel {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px;
}

.primary-btn {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border: none;
    padding: 15px 40px;
    font-size: 1.1rem;
    font-weight: 600;
    border-radius: 50px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: var(--shadow);
    display: flex;
    align-items: center;
    gap: 10px;
}

.primary-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
}

.primary-btn:active {
    transform: translateY(0);
}

.btn-icon {
    font-size: 1.4rem;
}

.player-controls {
    display: flex;
    align-items: center;
    gap: 20px;
    background: var(--light-bg);
    padding: 20px 30px;
    border-radius: 50px;
    box-shadow: var(--shadow);
}

.control-btn {
    background: var(--surface-bg);
    border: none;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    font-size: 1.4rem;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-primary);
}

.control-btn:hover {
    background: var(--primary-color);
    transform: scale(1.1);
}

.volume-control {
    display: flex;
    align-items: center;
    gap: 10px;
    flex: 1;
    max-width: 200px;
}

.volume-control span {
    font-size: 1.2rem;
}

.hidden {
    display: none !important;
}

.visualizer {
    background: var(--light-bg);
    border-radius: 12px;
    padding: 30px;
    box-shadow: var(--shadow);
}

#waveform {
    width: 100%;
    height: 200px;
    background: var(--dark-bg);
    border-radius: 8px;
    margin-bottom: 20px;
}

.status-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 20px;
}

.timer {
    font-size: 1.2rem;
    font-weight: 500;
    font-variant-numeric: tabular-nums;
}

.brain-wave {
    display: flex;
    align-items: center;
    gap: 10px;
}

.wave-label {
    color: var(--text-secondary);
}

.wave-state {
    color: var(--secondary-color);
    font-weight: 600;
}

.info-panel {
    background: var(--light-bg);
    border-radius: 12px;
    padding: 30px;
    box-shadow: var(--shadow);
}

.info-panel h3 {
    font-size: 1.3rem;
    margin-bottom: 20px;
    color: var(--primary-color);
}

.info-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
}

.info-card {
    background: var(--surface-bg);
    padding: 20px;
    border-radius: 8px;
    border-left: 4px solid var(--primary-color);
    transition: all 0.3s ease;
}

.info-card:hover {
    transform: translateX(5px);
    box-shadow: var(--shadow);
}

.info-card h4 {
    font-size: 1.1rem;
    margin-bottom: 10px;
    color: var(--secondary-color);
}

.info-card p {
    font-size: 0.95rem;
    color: var(--text-secondary);
    line-height: 1.5;
}

footer {
    text-align: center;
    padding: 40px 0;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* レスポンシブデザイン */
@media (max-width: 768px) {
    h1 {
        font-size: 2rem;
    }
    
    .subtitle {
        font-size: 1rem;
    }
    
    .config-panel, .visualizer, .info-panel {
        padding: 20px;
    }
    
    .player-controls {
        padding: 15px 20px;
        gap: 15px;
    }
    
    .control-btn {
        width: 40px;
        height: 40px;
        font-size: 1.2rem;
    }
    
    .info-cards {
        grid-template-columns: 1fr;
    }
}

/* アニメーション */
@keyframes pulse {
    0% {
        opacity: 1;
    }
    50% {
        opacity: 0.7;
    }
    100% {
        opacity: 1;
    }
}

.play-icon, .pause-icon {
    animation: pulse 2s infinite;
}

/* アクセシビリティ向上 */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}