/* CSS Variables */
:root {
    --primary-color: #4f46e5;
    --primary-hover: #4338ca;
    --secondary-color: #64748b;
    --secondary-hover: #475569;
    --danger-color: #ef4444;
    --danger-hover: #dc2626;
    --success-color: #22c55e;
    --warning-color: #f59e0b;
    --background: #f8fafc;
    --surface: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 1rem;
    --radius-full: 9999px;
}

/* Dark mode support */
@media (prefers-color-scheme: dark) {
    :root {
        --background: #0f172a;
        --surface: #1e293b;
        --text-primary: #f1f5f9;
        --text-secondary: #94a3b8;
        --border-color: #334155;
    }
}

/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: var(--background);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

/* App Container */
.app-container {
    max-width: 800px;
    margin: 0 auto;
    padding: 1rem;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header */
header {
    text-align: center;
    padding: 2rem 0;
}

header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    background: linear-gradient(135deg, var(--primary-color), #7c3aed);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

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

/* Main Content */
main {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

/* Timer Section */
.timer-section {
    background: var(--surface);
    border-radius: var(--radius-lg);
    padding: 2rem;
    box-shadow: var(--shadow-md);
    text-align: center;
}

.timer-display {
    display: flex;
    justify-content: center;
    margin-bottom: 2rem;
}

.timer-circle {
    position: relative;
    width: 280px;
    height: 280px;
}

.progress-ring {
    transform: rotate(-90deg);
}

.progress-ring-bg {
    fill: none;
    stroke: var(--border-color);
    stroke-width: 12;
}

.progress-ring-circle {
    fill: none;
    stroke: var(--primary-color);
    stroke-width: 12;
    stroke-linecap: round;
    stroke-dasharray: 816.81;
    stroke-dashoffset: 0;
    transition: stroke-dashoffset 1s linear;
}

.timer-content {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
}

.timer-time {
    display: block;
    font-size: 3.5rem;
    font-weight: 700;
    font-variant-numeric: tabular-nums;
    color: var(--text-primary);
}

.timer-label {
    display: block;
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-top: 0.25rem;
}

/* Timer Controls */
.timer-controls {
    display: flex;
    justify-content: center;
    gap: 1rem;
    flex-wrap: wrap;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 600;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all 0.2s ease;
}

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

.btn-icon {
    font-size: 0.9rem;
}

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

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

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

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

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

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

/* Modal */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.6);
    backdrop-filter: blur(4px);
    z-index: 1000;
    align-items: center;
    justify-content: center;
    padding: 1rem;
}

.modal.active {
    display: flex;
}

.modal-content {
    background: var(--surface);
    border-radius: var(--radius-lg);
    padding: 2.5rem;
    text-align: center;
    max-width: 400px;
    width: 100%;
    box-shadow: var(--shadow-lg);
    animation: modalSlideIn 0.3s ease;
}

@keyframes modalSlideIn {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.modal-icon {
    font-size: 4rem;
    margin-bottom: 1rem;
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.1);
    }
}

.modal-content h2 {
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.modal-content p {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

.break-timer {
    background: var(--background);
    border-radius: var(--radius-md);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
}

.break-timer span:first-child {
    display: block;
    font-size: 3rem;
    font-weight: 700;
    color: var(--primary-color);
}

.break-timer span:last-child {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* Statistics Section */
.stats-section {
    background: var(--surface);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    box-shadow: var(--shadow-md);
}

.stats-section h2 {
    font-size: 1.25rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1rem;
}

.stat-card {
    background: var(--background);
    border-radius: var(--radius-md);
    padding: 1.25rem;
    text-align: center;
}

.stat-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-color);
    font-variant-numeric: tabular-nums;
}

.stat-label {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-top: 0.25rem;
}

/* Settings Section */
.settings-section {
    background: var(--surface);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    box-shadow: var(--shadow-md);
}

.settings-section h2 {
    font-size: 1.25rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.settings-group {
    margin-bottom: 1.5rem;
}

.setting-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 0;
    border-bottom: 1px solid var(--border-color);
}

.setting-item:last-child {
    border-bottom: none;
}

.setting-item label {
    font-weight: 500;
    color: var(--text-primary);
}

.setting-item input[type="number"] {
    width: 80px;
    padding: 0.5rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    font-size: 1rem;
    text-align: center;
    background: var(--background);
    color: var(--text-primary);
}

.setting-item input[type="number"]:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

/* Toggle Switch */
.toggle {
    position: relative;
    display: inline-block;
    width: 52px;
    height: 28px;
}

.toggle input {
    opacity: 0;
    width: 0;
    height: 0;
}

.toggle-slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--border-color);
    border-radius: var(--radius-full);
    transition: 0.3s;
}

.toggle-slider:before {
    position: absolute;
    content: "";
    height: 22px;
    width: 22px;
    left: 3px;
    bottom: 3px;
    background: white;
    border-radius: 50%;
    transition: 0.3s;
    box-shadow: var(--shadow-sm);
}

.toggle input:checked + .toggle-slider {
    background: var(--primary-color);
}

.toggle input:checked + .toggle-slider:before {
    transform: translateX(24px);
}

/* Info Section */
.info-section {
    background: var(--surface);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    box-shadow: var(--shadow-md);
}

.info-section h2 {
    font-size: 1.25rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.info-content {
    color: var(--text-secondary);
}

.info-content p {
    margin-bottom: 1rem;
}

.info-content ul {
    list-style: none;
    padding-left: 0;
}

.info-content li {
    padding: 0.5rem 0;
    padding-left: 1.5rem;
    position: relative;
}

.info-content li::before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--success-color);
    font-weight: bold;
}

/* Footer */
footer {
    text-align: center;
    padding: 2rem 0;
    margin-top: auto;
    border-top: 1px solid var(--border-color);
}

footer p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

footer a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
}

footer a:hover {
    text-decoration: underline;
}

/* DND Mode Indicator */
.dnd-indicator {
    position: fixed;
    top: 1rem;
    right: 1rem;
    background: var(--warning-color);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: var(--radius-full);
    font-size: 0.85rem;
    font-weight: 600;
    display: none;
    z-index: 100;
    box-shadow: var(--shadow-md);
}

.dnd-indicator.active {
    display: block;
}

/* Responsive Design */
@media (max-width: 600px) {
    header h1 {
        font-size: 1.75rem;
    }

    .subtitle {
        font-size: 0.95rem;
    }

    .timer-circle {
        width: 220px;
        height: 220px;
    }

    .progress-ring {
        width: 220px;
        height: 220px;
    }

    .progress-ring-bg,
    .progress-ring-circle {
        cx: 110;
        cy: 110;
        r: 100;
    }

    .progress-ring-circle {
        stroke-dasharray: 628.32;
    }

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

    .timer-controls {
        gap: 0.5rem;
    }

    .btn {
        padding: 0.6rem 1rem;
        font-size: 0.9rem;
    }

    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 0.75rem;
    }

    .stat-value {
        font-size: 1.5rem;
    }

    .stat-label {
        font-size: 0.75rem;
    }

    .modal-content {
        padding: 1.5rem;
    }

    .modal-icon {
        font-size: 3rem;
    }

    .break-timer span:first-child {
        font-size: 2.5rem;
    }
}

@media (max-width: 400px) {
    .app-container {
        padding: 0.5rem;
    }

    .timer-section,
    .stats-section,
    .settings-section,
    .info-section {
        padding: 1rem;
    }

    .timer-controls {
        flex-direction: column;
    }

    .btn {
        width: 100%;
        justify-content: center;
    }
}

/* Animation for timer running state */
.timer-section.running .timer-circle {
    animation: glow 2s ease-in-out infinite;
}

@keyframes glow {
    0%, 100% {
        filter: drop-shadow(0 0 5px rgba(79, 70, 229, 0.3));
    }
    50% {
        filter: drop-shadow(0 0 15px rgba(79, 70, 229, 0.5));
    }
}

/* Break mode styling */
.timer-section.break-mode .progress-ring-circle {
    stroke: var(--success-color);
}

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

/* Notification toast */
.toast {
    position: fixed;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%);
    background: var(--text-primary);
    color: var(--background);
    padding: 1rem 2rem;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    z-index: 1001;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
}

.toast.show {
    opacity: 1;
    visibility: visible;
}