:root {
    --primary-color: #4A90E2;
    --secondary-color: #7B68EE;
    --danger-color: #E74C3C;
    --warning-color: #F39C12;
    --success-color: #27AE60;
    --bg-color: #F8F9FA;
    --card-bg: #FFFFFF;
    --text-primary: #2C3E50;
    --text-secondary: #7F8C8D;
    --border-color: #E1E8ED;
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.15);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.2);
    --border-radius: 12px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-primary);
    line-height: 1.6;
    padding: 20px;
}

.container {
    width: 100%;
    max-width: 800px;
    background: var(--card-bg);
    border-radius: 24px;
    box-shadow: var(--shadow-lg);
    overflow: hidden;
    animation: slideUp 0.5s ease-out;
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

header {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    padding: 24px 32px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: white;
}

header h1 {
    font-size: 28px;
    font-weight: 700;
    letter-spacing: -0.5px;
}

.language-selector select {
    background: rgba(255, 255, 255, 0.2);
    border: 1px solid rgba(255, 255, 255, 0.3);
    color: white;
    padding: 8px 16px;
    border-radius: 8px;
    font-size: 14px;
    cursor: pointer;
    transition: var(--transition);
    backdrop-filter: blur(10px);
}

.language-selector select:hover {
    background: rgba(255, 255, 255, 0.3);
}

.language-selector select option {
    background: var(--primary-color);
    color: white;
}

main {
    padding: 32px;
}

.timer-display {
    text-align: center;
    margin-bottom: 40px;
    padding: 40px;
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    border-radius: 20px;
    position: relative;
    overflow: hidden;
}

.timer-display::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(255, 255, 255, 0.1) 0%, transparent 70%);
    animation: rotate 20s linear infinite;
}

@keyframes rotate {
    from {
        transform: rotate(0deg);
    }
    to {
        transform: rotate(360deg);
    }
}

.time-display {
    font-size: 72px;
    font-weight: 700;
    font-variant-numeric: tabular-nums;
    letter-spacing: -2px;
    color: var(--text-primary);
    margin-bottom: 24px;
    transition: var(--transition);
    position: relative;
    z-index: 1;
}

.time-display.warning {
    color: var(--danger-color);
    animation: pulse 1s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.05);
    }
}

.progress-container {
    width: 100%;
    height: 24px;
    background: rgba(255, 255, 255, 0.8);
    border-radius: 12px;
    overflow: hidden;
    position: relative;
    margin-bottom: 20px;
    box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.1);
}

.progress-bar {
    height: 100%;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    width: 0%;
    transition: width 1s linear;
    border-radius: 12px;
    position: relative;
    overflow: hidden;
}

.progress-bar::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    bottom: 0;
    right: 0;
    background: linear-gradient(
        90deg,
        transparent,
        rgba(255, 255, 255, 0.3),
        transparent
    );
    animation: shimmer 2s infinite;
}

@keyframes shimmer {
    0% {
        transform: translateX(-100%);
    }
    100% {
        transform: translateX(100%);
    }
}

.progress-bar.warning {
    background: linear-gradient(90deg, var(--warning-color), var(--danger-color));
}

.progress-markers {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    pointer-events: none;
}

.section-marker {
    position: absolute;
    top: 0;
    bottom: 0;
    width: 2px;
    background: rgba(0, 0, 0, 0.3);
    box-shadow: 0 0 4px rgba(0, 0, 0, 0.2);
}

.section-indicator {
    font-size: 18px;
    color: var(--text-secondary);
    font-weight: 500;
    position: relative;
    z-index: 1;
}

.controls {
    display: flex;
    gap: 16px;
    justify-content: center;
    margin-bottom: 40px;
    flex-wrap: wrap;
}

.btn {
    padding: 14px 32px;
    border: none;
    border-radius: 12px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    position: relative;
    overflow: hidden;
    box-shadow: var(--shadow-md);
}

.btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.3);
    transform: translate(-50%, -50%);
    transition: width 0.6s, height 0.6s;
}

.btn:active::before {
    width: 300px;
    height: 300px;
}

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

.btn-primary:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background: linear-gradient(135deg, #95a5a6, #7f8c8d);
    color: white;
}

.btn-secondary:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-danger {
    background: linear-gradient(135deg, var(--danger-color), #c0392b);
    color: white;
}

.btn-danger:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

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

.settings-panel {
    background: var(--bg-color);
    padding: 24px;
    border-radius: 16px;
    margin-bottom: 32px;
}

.settings-panel h2 {
    font-size: 20px;
    margin-bottom: 20px;
    color: var(--text-primary);
    font-weight: 600;
}

.setting-group {
    margin-bottom: 20px;
}

.setting-group label {
    display: block;
    margin-bottom: 8px;
    color: var(--text-secondary);
    font-size: 14px;
    font-weight: 500;
}

.setting-group input[type="number"] {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 16px;
    transition: var(--transition);
    background: white;
}

.setting-group input[type="number"]:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(74, 144, 226, 0.1);
}

.checkbox-label {
    display: flex;
    align-items: center;
    cursor: pointer;
    user-select: none;
}

.checkbox-label input[type="checkbox"] {
    width: 20px;
    height: 20px;
    margin-right: 12px;
    cursor: pointer;
    accent-color: var(--primary-color);
}

.section-times {
    display: grid;
    gap: 16px;
    margin-top: 16px;
}

.section-time-input {
    display: flex;
    align-items: center;
    gap: 12px;
}

.section-time-input label {
    flex: 1;
    margin: 0;
}

.section-time-input input {
    width: 120px;
}

.presets {
    background: var(--bg-color);
    padding: 24px;
    border-radius: 16px;
}

.presets h3 {
    font-size: 18px;
    margin-bottom: 16px;
    color: var(--text-primary);
    font-weight: 600;
}

.preset-buttons {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 12px;
}

.preset-btn {
    padding: 12px 20px;
    background: white;
    border: 2px solid var(--border-color);
    border-radius: 10px;
    cursor: pointer;
    transition: var(--transition);
    font-size: 14px;
    font-weight: 500;
    color: var(--text-primary);
}

.preset-btn:hover:not(:disabled) {
    border-color: var(--primary-color);
    background: linear-gradient(135deg, rgba(74, 144, 226, 0.1), rgba(123, 104, 238, 0.1));
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

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

/* レスポンシブデザイン */
@media (max-width: 768px) {
    .container {
        border-radius: 20px;
        margin: 10px;
    }
    
    header {
        padding: 20px;
        flex-direction: column;
        gap: 16px;
    }
    
    header h1 {
        font-size: 24px;
    }
    
    main {
        padding: 24px;
    }
    
    .time-display {
        font-size: 56px;
    }
    
    .timer-display {
        padding: 24px;
    }
    
    .controls {
        flex-direction: column;
    }
    
    .btn {
        width: 100%;
    }
    
    .preset-buttons {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .time-display {
        font-size: 48px;
    }
    
    header h1 {
        font-size: 20px;
    }
    
    main {
        padding: 16px;
    }
}