:root {
    /* Light Mode Variables */
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --secondary-color: #7c3aed;
    --bg-color: #f8fafc;
    --card-bg: #ffffff;
    --text-color: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --danger-color: #ef4444;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --border-radius: 12px;
    --transition: all 0.2s ease;
}

.dark-mode {
    /* Dark Mode Variables */
    --primary-color: #3b82f6;
    --primary-hover: #60a5fa;
    --secondary-color: #8b5cf6;
    --bg-color: #0f172a;
    --card-bg: #1e293b;
    --text-color: #f1f5f9;
    --text-secondary: #94a3b8;
    --border-color: #334155;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3), 0 2px 4px -1px rgba(0, 0, 0, 0.2);
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    transition: var(--transition);
    min-height: 100vh;
}

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

/* Header & Navigation */
header {
    padding: 20px 0;
    border-bottom: 1px solid var(--border-color);
    margin-bottom: 30px;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
}

.logo-icon {
    font-size: 1.8rem;
    color: var(--primary-color);
}

.logo-text {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-color);
}

nav {
    display: flex;
    gap: 5px;
}

.nav-link {
    padding: 10px 18px;
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    border-radius: 8px;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 8px;
}

.nav-link:hover {
    color: var(--primary-color);
    background-color: rgba(37, 99, 235, 0.05);
}

.nav-link.active {
    color: var(--primary-color);
    background-color: rgba(37, 99, 235, 0.1);
}

.header-controls {
    display: flex;
    align-items: center;
    gap: 15px;
}

/* Theme Toggle */
.theme-toggle {
    display: flex;
    align-items: center;
    gap: 8px;
}

.toggle-switch {
    position: relative;
    display: inline-block;
    width: 52px;
    height: 26px;
}

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

.toggle-slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #cbd5e1;
    border-radius: 34px;
    transition: var(--transition);
}

.toggle-slider:before {
    position: absolute;
    content: "";
    height: 18px;
    width: 18px;
    left: 4px;
    bottom: 4px;
    background-color: white;
    border-radius: 50%;
    transition: var(--transition);
}

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

input:checked + .toggle-slider:before {
    transform: translateX(26px);
}

/* AD PLACEMENT ZONE 1: Header Banner (Horizontal Banner 728x90 or 970x90) */
.ad-header {
    max-width: 970px;
    margin: 20px auto;
    text-align: center;
    min-height: 90px;
    background-color: rgba(0, 0, 0, 0.02);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Page Content */
.page {
    display: block;
    animation: fadeIn 0.3s ease;
}

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

.page-header {
    margin-bottom: 30px;
    text-align: center;
}

.page-title {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.page-description {
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
    font-size: 1.1rem;
    line-height: 1.8;
}

/* SEO Content Section */
.seo-content {
    max-width: 800px;
    margin: 40px auto;
    padding: 30px;
    background-color: var(--card-bg);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
}

.seo-content h2 {
    font-size: 1.8rem;
    margin-bottom: 15px;
    color: var(--text-color);
}

.seo-content h3 {
    font-size: 1.4rem;
    margin-top: 25px;
    margin-bottom: 12px;
    color: var(--text-color);
}

.seo-content p {
    margin-bottom: 15px;
    line-height: 1.8;
    color: var(--text-secondary);
}

.seo-content ul {
    margin-left: 25px;
    margin-bottom: 15px;
}

.seo-content ul li {
    margin-bottom: 8px;
    color: var(--text-secondary);
}

/* Timer Cards */
.timer-card {
    background-color: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 40px;
    box-shadow: var(--shadow);
    max-width: 600px;
    margin: 20px auto;
    position: relative;
}

/* AD PLACEMENT ZONE 2: Sidebar (Medium Rectangle 300x250) */
.ad-sidebar {
    width: 300px;
    min-height: 250px;
    background-color: rgba(0, 0, 0, 0.02);
    border-radius: 8px;
    margin: 20px 0;
    display: flex;
    align-items: center;
    justify-content: center;
}

.time-display {
    font-size: 4rem;
    font-weight: 700;
    font-variant-numeric: tabular-nums;
    text-align: center;
    margin: 30px 0;
    color: var(--text-color);
    font-feature-settings: "tnum";
}

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

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

@keyframes pulse {
    0% { opacity: 1; }
    50% { opacity: 0.7; }
    100% { opacity: 1; }
}

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

.btn {
    padding: 14px 28px;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    transition: var(--transition);
    min-width: 120px;
}

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

.btn-primary:hover:not(:disabled) {
    background-color: var(--primary-hover);
    transform: translateY(-2px);
}

.btn-secondary {
    background-color: rgba(37, 99, 235, 0.1);
    color: var(--primary-color);
}

.btn-secondary:hover:not(:disabled) {
    background-color: rgba(37, 99, 235, 0.2);
    transform: translateY(-2px);
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none !important;
}

/* Timer Inputs */
.time-inputs {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin: 30px 0;
    flex-wrap: wrap;
}

.time-input {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.time-input label {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: 8px;
    text-transform: uppercase;
}

.time-input input {
    width: 80px;
    padding: 12px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1.3rem;
    font-weight: 600;
    text-align: center;
    color: var(--text-color);
    background-color: var(--bg-color);
    transition: var(--transition);
}

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

/* Alarm Section */
.alarm-section {
    margin-top: 30px;
    padding-top: 25px;
    border-top: 1px solid var(--border-color);
}

.alarm-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 15px;
    cursor: pointer;
    padding: 10px;
    border-radius: 8px;
    background-color: rgba(0, 0, 0, 0.02);
}

.alarm-header:hover {
    background-color: rgba(0, 0, 0, 0.04);
}

.alarm-header h3 {
    font-size: 1.2rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 10px;
}

.alarm-content {
    display: none;
    padding: 20px;
    background-color: rgba(0, 0, 0, 0.02);
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.alarm-content.active {
    display: block;
}

.sound-options {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: 15px;
    margin-bottom: 20px;
}

.sound-option {
    padding: 15px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    cursor: pointer;
    transition: var(--transition);
    text-align: center;
    background-color: var(--bg-color);
}

.sound-option:hover {
    border-color: var(--primary-color);
    transform: translateY(-2px);
}

.sound-option.active {
    border-color: var(--primary-color);
    background-color: rgba(37, 99, 235, 0.1);
}

.sound-icon {
    font-size: 1.5rem;
    margin-bottom: 8px;
    color: var(--primary-color);
}

.sound-name {
    font-weight: 600;
    margin-bottom: 4px;
}

.sound-desc {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.sound-preview {
    margin-top: 8px;
}

.preview-btn {
    padding: 6px 12px;
    font-size: 0.8rem;
    background-color: rgba(37, 99, 235, 0.1);
    border: none;
    border-radius: 4px;
    color: var(--primary-color);
    cursor: pointer;
    transition: var(--transition);
}

.preview-btn:hover {
    background-color: rgba(37, 99, 235, 0.2);
}

.custom-sound {
    margin-top: 20px;
    padding: 20px;
    background-color: rgba(0, 0, 0, 0.02);
    border-radius: 8px;
}

.file-upload {
    display: flex;
    gap: 15px;
    align-items: center;
    margin-top: 10px;
}

.file-input {
    flex: 1;
    padding: 10px;
    border: 2px dashed var(--border-color);
    border-radius: 8px;
    background-color: var(--bg-color);
    color: var(--text-color);
}

.test-sound-btn {
    width: 100%;
    margin-top: 15px;
}

/* Laps */
.laps-container {
    max-height: 300px;
    overflow-y: auto;
    margin-top: 30px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 15px;
}

.laps-header {
    display: flex;
    justify-content: space-between;
    padding: 15px 0;
    border-bottom: 2px solid var(--border-color);
    font-weight: 600;
    color: var(--text-secondary);
    position: sticky;
    top: 0;
    background-color: var(--card-bg);
}

.lap-item {
    display: flex;
    justify-content: space-between;
    padding: 12px 0;
    border-bottom: 1px solid var(--border-color);
}

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

.lap-number {
    font-weight: 600;
    color: var(--primary-color);
}

.lap-time {
    font-weight: 600;
    font-variant-numeric: tabular-nums;
}

/* Pomodoro */
.pomodoro-controls {
    display: flex;
    justify-content: center;
    gap: 10px;
    margin: 25px 0;
}

.pomodoro-btn {
    padding: 10px 20px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    background: transparent;
    color: var(--text-color);
    cursor: pointer;
    font-weight: 600;
    transition: var(--transition);
}

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

.pomodoro-info {
    text-align: center;
    margin-top: 20px;
    color: var(--text-secondary);
}

.session-count {
    font-weight: 600;
    color: var(--primary-color);
}

/* Interval Timer */
.interval-settings {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin: 30px 0;
}

.interval-setting {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.interval-setting label {
    font-weight: 600;
    color: var(--text-color);
}

.interval-setting input {
    padding: 12px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1.1rem;
    background-color: var(--bg-color);
    color: var(--text-color);
}

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

.interval-display {
    text-align: center;
    margin: 30px 0;
    padding: 20px;
    background-color: rgba(0, 0, 0, 0.02);
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.interval-type {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: 10px;
}

.interval-progress {
    height: 6px;
    background-color: var(--border-color);
    border-radius: 3px;
    margin: 20px 0;
    overflow: hidden;
}

.interval-progress-bar {
    height: 100%;
    background-color: var(--primary-color);
    width: 0%;
    transition: width 0.5s ease;
}

/* Footer Pages Styling */
.footer-page-content {
    max-width: 900px;
    margin: 0 auto;
    padding: 40px 20px;
}

.footer-page-content h1 {
    font-size: 2.5rem;
    margin-bottom: 30px;
    color: var(--text-color);
}

.footer-page-content h2 {
    font-size: 1.8rem;
    margin-top: 35px;
    margin-bottom: 15px;
    color: var(--text-color);
}

.footer-page-content h3 {
    font-size: 1.4rem;
    margin-top: 25px;
    margin-bottom: 12px;
    color: var(--text-color);
}

.footer-page-content p {
    margin-bottom: 18px;
    line-height: 1.8;
    color: var(--text-secondary);
}

.footer-page-content ul {
    margin-left: 30px;
    margin-bottom: 20px;
}

.footer-page-content ul li {
    margin-bottom: 10px;
    color: var(--text-secondary);
    line-height: 1.7;
}

.contact-info {
    background-color: var(--card-bg);
    padding: 25px;
    border-radius: var(--border-radius);
    margin: 25px 0;
    box-shadow: var(--shadow);
}

.contact-info p {
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.contact-info i {
    color: var(--primary-color);
    width: 20px;
}

/* Footer */
footer {
    text-align: center;
    margin-top: 50px;
    padding: 40px 0 25px 0;
    color: var(--text-secondary);
    font-size: 0.9rem;
    border-top: 1px solid var(--border-color);
    background-color: var(--card-bg);
}

.footer-nav {
    display: flex;
    justify-content: center;
    gap: 25px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.footer-nav a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: var(--transition);
    font-weight: 500;
}

.footer-nav a:hover {
    color: var(--primary-color);
}

/* AD PLACEMENT ZONE 3: In-Content (Rectangle 300x250 or Large Rectangle 336x280) */
.ad-in-content {
    max-width: 336px;
    min-height: 280px;
    margin: 30px auto;
    background-color: rgba(0, 0, 0, 0.02);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Responsive */
@media (max-width: 768px) {
    .header-content {
        flex-direction: column;
        gap: 20px;
    }
    
    nav {
        flex-wrap: wrap;
        justify-content: center;
    }
    
    .time-display {
        font-size: 3rem;
    }
    
    .timer-card {
        padding: 30px 20px;
    }
    
    .time-inputs {
        gap: 10px;
    }
    
    .time-input input {
        width: 70px;
        font-size: 1.2rem;
    }
    
    .sound-options {
        grid-template-columns: 1fr;
    }
    
    .timer-controls {
        gap: 10px;
    }
    
    .btn {
        min-width: 110px;
        padding: 12px 20px;
    }

    .footer-nav {
        flex-direction: column;
        gap: 15px;
    }
}

@media (max-width: 480px) {
    .time-display {
        font-size: 2.5rem;
    }
    
    .time-input input {
        width: 60px;
        font-size: 1.1rem;
        padding: 10px;
    }
    
    .btn {
        min-width: 100px;
        padding: 10px 15px;
        font-size: 0.9rem;
    }
    
    .timer-card {
        padding: 20px 15px;
    }
    
    .time-inputs {
        gap: 8px;
    }
    /* Timer running states */
.timer-running {
    border: 2px solid var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.stopwatch-running {
    border: 2px solid var(--success-color);
    box-shadow: 0 0 0 3px rgba(16, 185, 129, 0.1);
}

.pomodoro-running {
    border: 2px solid var(--warning-color);
    box-shadow: 0 0 0 3px rgba(245, 158, 11, 0.1);
}

.interval-running {
    border: 2px solid var(--secondary-color);
    box-shadow: 0 0 0 3px rgba(124, 58, 237, 0.1);
}

/* Lap highlighting */
.fastest-lap {
    color: var(--success-color) !important;
    font-weight: 700;
}

.slowest-lap {
    color: var(--danger-color) !important;
    font-weight: 700;
}

/* Active timer indicator */
.active-timer-indicator {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background-color: var(--primary-color);
    color: white;
    padding: 10px 15px;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 600;
    z-index: 1000;
    box-shadow: var(--shadow);
    animation: pulse 2s infinite;
}

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

/* Timer name input */
.timer-name {
    font-size: 1.2rem !important;
    font-weight: 600 !important;
    background: transparent !important;
    border: none !important;
    color: var(--text-color) !important;
    padding: 5px 10px !important;
    border-radius: 5px !important;
    min-width: 150px !important;
    border: 2px solid transparent !important;
}

.timer-name:focus {
    outline: none !important;
    border: 2px solid var(--primary-color) !important;
    background-color: rgba(37, 99, 235, 0.05) !important;
}

/* Delete button */
.delete-timer-btn {
    background: none !important;
    border: none !important;
    color: var(--danger-color) !important;
    cursor: pointer !important;
    font-size: 1.2rem !important;
    padding: 5px !important;
    border-radius: 4px !important;
}

.delete-timer-btn:hover {
    background-color: rgba(239, 68, 68, 0.1) !important;
}
}