/* 기본 스타일 초기화 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* CSS 변수 정의 - 밝은 테마 */
:root {
    --primary-color: #ff6b6b;
    --primary-hover: #ff5252;
    --secondary-color: #4ecdc4;
    --success-color: #51cf66;
    --warning-color: #ffd43b;
    --danger-color: #ff8787;
    --background-color: #f8f9fa;
    --card-background: #ffffff;
    --text-primary: #212529;
    --text-secondary: #6c757d;
    --border-color: #dee2e6;
    --shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    --border-radius: 12px;
    --transition: all 0.3s ease;
}

/* 어두운 테마 */
[data-theme="dark"] {
    --primary-color: #8b5cf6;
    --primary-hover: #7c3aed;
    --secondary-color: #4ecdc4;
    --success-color: #51cf66;
    --warning-color: #ffd43b;
    --danger-color: #a855f7;
    --background-color: #1a1a1a;
    --card-background: #2d2d2d;
    --text-primary: #ffffff;
    --text-secondary: #b0b0b0;
    --border-color: #404040;
    --shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
}

/* 시스템 설정에 따른 다크 모드 */
@media (prefers-color-scheme: dark) {
    [data-theme="auto"] {
        --primary-color: #8b5cf6;
        --primary-hover: #7c3aed;
        --secondary-color: #4ecdc4;
        --success-color: #51cf66;
        --warning-color: #ffd43b;
        --danger-color: #a855f7;
        --background-color: #1a1a1a;
        --card-background: #2d2d2d;
        --text-primary: #ffffff;
        --text-secondary: #b0b0b0;
        --border-color: #404040;
        --shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
    }
}

/* 기본 스타일 */
body {
    font-family: 'Noto Sans KR', sans-serif;
    background-color: var(--background-color);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
    transition: var(--transition);
}

.container {
    width: 100%;
    max-width: 600px;
    background: var(--card-background);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    padding: 40px;
    text-align: center;
}

/* 헤더 스타일 */
header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 10px;
    color: var(--primary-color);
}

.subtitle {
    color: var(--text-secondary);
    font-size: 1.1rem;
    margin-bottom: 40px;
}

/* 모드 선택기 */
.mode-selector {
    display: flex;
    gap: 10px;
    margin-bottom: 30px;
    background: var(--background-color);
    padding: 5px;
    border-radius: var(--border-radius);
}

.mode-btn {
    flex: 1;
    padding: 12px 20px;
    border: none;
    background: transparent;
    color: var(--text-secondary);
    border-radius: calc(var(--border-radius) - 5px);
    cursor: pointer;
    transition: var(--transition);
    font-weight: 500;
}

.mode-btn.active {
    background: var(--card-background);
    color: var(--primary-color);
    box-shadow: var(--shadow);
}

.mode-btn:hover:not(.active) {
    background: var(--border-color);
    color: var(--text-primary);
}

/* 타이머 디스플레이 */
.timer-display {
    margin-bottom: 30px;
}

.time {
    font-size: 4rem;
    font-weight: 300;
    color: var(--primary-color);
    margin-bottom: 10px;
    font-variant-numeric: tabular-nums;
}

.session-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: var(--text-secondary);
    font-size: 1.1rem;
}

/* 타이머 컨트롤 */
.timer-controls {
    display: flex;
    gap: 15px;
    justify-content: center;
    margin-bottom: 30px;
}

.control-btn {
    padding: 15px 30px;
    border: none;
    border-radius: var(--border-radius);
    font-size: 1.1rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    min-width: 120px;
}

.control-btn.primary {
    background: var(--primary-color);
    color: white;
}

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

.control-btn.secondary {
    background: var(--background-color);
    color: var(--text-primary);
    border: 2px solid var(--border-color);
}

.control-btn.secondary:hover {
    background: var(--border-color);
    transform: translateY(-2px);
}

.control-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none !important;
}

/* 프로그레스 바 */
.progress-bar {
    width: 100%;
    height: 8px;
    background: var(--background-color);
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 40px;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    border-radius: 4px;
    transition: width 1s linear;
    width: 0%;
}

/* 통계 섹션 */
.stats-section {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.stat-card {
    background: var(--background-color);
    padding: 20px;
    border-radius: var(--border-radius);
    border: 2px solid var(--border-color);
    transition: var(--transition);
}

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

.stat-card h3 {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 10px;
    font-weight: 500;
}

.stat-number {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 5px;
}

.stat-label {
    font-size: 0.8rem;
    color: var(--text-secondary);
}

/* 설정 버튼 */
.settings-btn {
    padding: 12px 24px;
    background: var(--background-color);
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 1rem;
    transition: var(--transition);
    color: var(--text-primary);
}

.settings-btn:hover {
    background: var(--border-color);
    transform: translateY(-2px);
}

/* 모달 스타일 */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    z-index: 1000;
    animation: fadeIn 0.3s ease;
}

.modal.show {
    display: flex;
    align-items: center;
    justify-content: center;
}

.modal-content {
    background: var(--card-background);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    width: 90%;
    max-width: 500px;
    max-height: 80vh;
    overflow-y: auto;
    animation: slideIn 0.3s ease;
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 30px;
    border-bottom: 2px solid var(--border-color);
}

.modal-header h2 {
    color: var(--primary-color);
    font-size: 1.5rem;
}

.close-btn {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-secondary);
    transition: var(--transition);
}

.close-btn:hover {
    color: var(--primary-color);
}

.modal-body {
    padding: 30px;
}

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

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

.setting-group input[type="number"] {
    width: 100%;
    padding: 12px;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 1rem;
    background: var(--background-color);
    color: var(--text-primary);
    transition: var(--transition);
}

.setting-group input[type="number"]:focus {
    outline: none;
    border-color: var(--primary-color);
}

.setting-group input[type="checkbox"] {
    margin-right: 10px;
    transform: scale(1.2);
}

.setting-group select {
    width: 100%;
    padding: 12px;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 1rem;
    background: var(--card-background);
    color: var(--text-primary);
    transition: var(--transition);
    cursor: pointer;
}

.setting-group select:focus {
    outline: none;
    border-color: var(--primary-color);
}

.modal-footer {
    display: flex;
    gap: 15px;
    justify-content: flex-end;
    padding: 20px 30px;
    border-top: 2px solid var(--border-color);
}

.btn {
    padding: 12px 24px;
    border: none;
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
}

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

.btn.primary:hover {
    background: var(--primary-hover);
}

.btn.secondary {
    background: var(--background-color);
    color: var(--text-primary);
    border: 2px solid var(--border-color);
}

.btn.secondary:hover {
    background: var(--border-color);
}

/* 토스트 알림 */
.toast {
    position: fixed;
    top: 20px;
    right: 20px;
    background: var(--success-color);
    color: white;
    padding: 15px 20px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    transform: translateX(400px);
    transition: var(--transition);
    z-index: 1001;
    font-weight: 500;
}

.toast.show {
    transform: translateX(0);
}

.toast.error {
    background: var(--danger-color);
}

.toast.warning {
    background: var(--warning-color);
    color: var(--text-primary);
}

/* 애니메이션 */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateY(-50px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

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

.pulse {
    animation: pulse 0.6s ease-in-out;
}

/* 반응형 디자인 */
@media (max-width: 768px) {
    .container {
        padding: 20px;
        margin: 10px;
    }

    header h1 {
        font-size: 2rem;
    }

    .time {
        font-size: 3rem;
    }

    .timer-controls {
        flex-direction: column;
        align-items: center;
    }

    .control-btn {
        width: 100%;
        max-width: 250px;
    }

    .stats-section {
        grid-template-columns: 1fr;
    }

    .modal-content {
        margin: 20px;
        width: calc(100% - 40px);
    }

    .modal-footer {
        flex-direction: column;
    }

    .btn {
        width: 100%;
    }
}

@media (max-width: 480px) {
    .mode-selector {
        flex-direction: column;
    }

    .session-info {
        flex-direction: column;
        gap: 5px;
    }

    .time {
        font-size: 2.5rem;
    }
}

/* 접근성 개선 */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* 포커스 스타일 */
button:focus,
input:focus {
    outline: 3px solid var(--primary-color);
    outline-offset: 2px;
}

/* 활성 상태 스타일 */
.timer-display.active .time {
    color: var(--secondary-color);
}

.timer-display.break .time {
    color: var(--success-color);
}

.timer-display.paused .time {
    color: var(--warning-color);
}