/* CSS Variables for consistent theming */
:root {
    --primary-color: #7868E6;
    --secondary-color: #B8B5FF;
    --accent-color: #FFB4B4;
    --background-color: #EDEEF7;
    --surface-color: #E4FBFF;
    --text-primary: #2D3748;
    --text-secondary: #4A5568;
    --text-muted: #718096;
    --border-color: #E2E8F0;
    --shadow-light: 0 2px 4px rgba(0, 0, 0, 0.1);
    --shadow-medium: 0 4px 8px rgba(0, 0, 0, 0.15);
    --shadow-heavy: 0 8px 16px rgba(0, 0, 0, 0.2);
    --border-radius: 8px;
    --transition: all 0.3s ease;
    --font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

/* Reset and base styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    background-color: var(--background-color);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    
    /* Paper texture effect */
    background-image: 
        radial-gradient(circle at 20% 80%, rgba(120, 119, 198, 0.3) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(255, 180, 180, 0.3) 0%, transparent 50%),
        radial-gradient(circle at 40% 40%, rgba(228, 251, 255, 0.5) 0%, transparent 50%);
    background-attachment: fixed;
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

/* Header */
.header {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 2rem 0;
    text-align: center;
    box-shadow: var(--shadow-medium);
}

.header__title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
}

.header__subtitle {
    font-size: 1.2rem;
    opacity: 0.9;
    font-weight: 300;
}

/* Navigation */
.navigation {
    background: white;
    box-shadow: var(--shadow-light);
    position: sticky;
    top: 0;
    z-index: 100;
}

.navigation__list {
    list-style: none;
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 0.5rem;
    padding: 1rem 0;
}

.navigation__button {
    background: none;
    border: none;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 500;
    color: var(--text-secondary);
    cursor: pointer;
    border-radius: var(--border-radius);
    transition: var(--transition);
    position: relative;
}

.navigation__button:hover {
    background-color: var(--surface-color);
    color: var(--primary-color);
}

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

.navigation__button:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* Main content */
.main {
    flex: 1;
    padding: 2rem 0;
}

/* Tab content */
.tab-content {
    display: none;
    animation: fadeIn 0.3s ease-in-out;
}

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

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Section titles */
.section__title {
    font-size: 2rem;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    text-align: center;
}

/* Timer Section */
.timer-section {
    max-width: 600px;
    margin: 0 auto;
}

.timer-display {
    background: white;
    border-radius: var(--border-radius);
    padding: 3rem 2rem;
    text-align: center;
    margin-bottom: 2rem;
    box-shadow: var(--shadow-medium);
    border: 2px solid var(--surface-color);
}

.timer-display__time {
    font-size: 4rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 1rem;
    font-family: 'Courier New', monospace;
}

.timer-display__status {
    font-size: 1.2rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.timer-controls {
    display: flex;
    gap: 1rem;
    justify-content: center;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

/* Buttons */
.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    min-width: 120px;
}

.btn:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

.btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

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

.btn--primary:hover:not(:disabled) {
    background-color: #6B5CE6;
    transform: translateY(-2px);
    box-shadow: var(--shadow-medium);
}

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

.btn--secondary:hover:not(:disabled) {
    background-color: #A5A2FF;
    transform: translateY(-2px);
    box-shadow: var(--shadow-medium);
}

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

.btn--danger:hover:not(:disabled) {
    background-color: #FF9999;
    transform: translateY(-2px);
    box-shadow: var(--shadow-medium);
}

.btn--large {
    padding: 1rem 2rem;
    font-size: 1.1rem;
    min-width: 180px;
}

.btn--small {
    padding: 0.5rem 1rem;
    font-size: 0.9rem;
    min-width: 100px;
}

/* Forms */
.contraction-form {
    background: white;
    border-radius: var(--border-radius);
    padding: 2rem;
    margin-bottom: 2rem;
    box-shadow: var(--shadow-medium);
    border: 2px solid var(--surface-color);
}

.form__title {
    font-size: 1.5rem;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    text-align: center;
}

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

.form-label {
    display: block;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.form-input,
.form-select,
.form-textarea {
    width: 100%;
    padding: 0.75rem;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
    background-color: white;
}

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(120, 104, 230, 0.1);
}

.form-range {
    width: 100%;
    height: 8px;
    border-radius: 5px;
    background: var(--border-color);
    outline: none;
    -webkit-appearance: none;
}

.form-range::-webkit-slider-thumb {
    appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--primary-color);
    cursor: pointer;
}

.form-range::-moz-range-thumb {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--primary-color);
    cursor: pointer;
    border: none;
}

.form-range__value {
    display: inline-block;
    margin-left: 1rem;
    font-weight: 600;
    color: var(--primary-color);
    font-size: 1.2rem;
}

.form-help {
    display: block;
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-top: 0.25rem;
}

.form-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
    margin-top: 2rem;
    flex-wrap: wrap;
}

/* Checkbox styles */
.form-checkbox {
    display: flex;
    align-items: center;
    cursor: pointer;
    font-weight: 500;
}

.form-checkbox input[type="checkbox"] {
    display: none;
}

.checkbox__checkmark {
    width: 20px;
    height: 20px;
    border: 2px solid var(--border-color);
    border-radius: 4px;
    margin-right: 0.75rem;
    position: relative;
    transition: var(--transition);
}

.form-checkbox input[type="checkbox"]:checked + .checkbox__checkmark {
    background-color: var(--primary-color);
    border-color: var(--primary-color);
}

.form-checkbox input[type="checkbox"]:checked + .checkbox__checkmark::after {
    content: '✓';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: white;
    font-weight: bold;
}

/* Current session */
.current-session {
    background: white;
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow-medium);
    border: 2px solid var(--surface-color);
}

.session__title {
    font-size: 1.5rem;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    text-align: center;
}

.session__stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
}

.stat {
    text-align: center;
    padding: 1rem;
    background: var(--surface-color);
    border-radius: var(--border-radius);
}

.stat__label {
    display: block;
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-bottom: 0.5rem;
}

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

/* History section */
.history-section {
    max-width: 800px;
    margin: 0 auto;
}

.history-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    flex-wrap: wrap;
    gap: 1rem;
}

.history-controls {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.history-filters {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.filter-group {
    flex: 1;
    min-width: 200px;
}

.history-list {
    background: white;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-medium);
    overflow: hidden;
}

.history-item {
    padding: 1.5rem;
    border-bottom: 1px solid var(--border-color);
    transition: var(--transition);
}

.history-item:hover {
    background-color: var(--surface-color);
}

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

.history-item__header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.5rem;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.history-item__date {
    font-weight: 600;
    color: var(--primary-color);
}

.history-item__type {
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
}

.history-item__type--braxton-hicks {
    background-color: var(--secondary-color);
    color: white;
}

.history-item__type--labor {
    background-color: var(--accent-color);
    color: white;
}

.history-item__type--uncertain {
    background-color: var(--text-muted);
    color: white;
}

.history-item__details {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 1rem;
    margin-bottom: 0.5rem;
}

.history-item__detail {
    text-align: center;
}

.history-item__detail-label {
    display: block;
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-bottom: 0.25rem;
}

.history-item__detail-value {
    font-weight: 600;
    color: var(--text-primary);
}

.history-item__notes {
    margin-top: 1rem;
    padding: 1rem;
    background-color: var(--surface-color);
    border-radius: var(--border-radius);
    font-style: italic;
    color: var(--text-secondary);
}

/* Analysis section */
.analysis-section {
    max-width: 1000px;
    margin: 0 auto;
}

.analysis-summary {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.summary-card {
    background: white;
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow-medium);
    border: 2px solid var(--surface-color);
}

.card__title {
    font-size: 1.5rem;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    text-align: center;
}

.summary-stats {
    display: grid;
    gap: 1rem;
}

.labor-alert {
    text-align: center;
}

.alert-indicator {
    margin-bottom: 1.5rem;
}

.indicator__status {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: 25px;
    font-weight: 600;
    font-size: 1.1rem;
}

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

.indicator__status--warning {
    background-color: #FFA500;
    color: white;
}

.indicator__status--alert {
    background-color: var(--accent-color);
    color: white;
}

.alert-criteria {
    text-align: left;
}

.alert-criteria ul {
    list-style-type: none;
    padding-left: 0;
}

.alert-criteria li {
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--border-color);
}

.alert-criteria li:last-child {
    border-bottom: none;
}

.alert-criteria li::before {
    content: '•';
    color: var(--primary-color);
    font-weight: bold;
    margin-right: 0.5rem;
}

.chart-container {
    background: white;
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow-medium);
    border: 2px solid var(--surface-color);
}

.chart__title {
    font-size: 1.5rem;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    text-align: center;
}

#contractions-chart {
    width: 100%;
    height: 400px;
    max-width: 100%;
}

/* Settings section */
.settings-section {
    max-width: 600px;
    margin: 0 auto;
}

.settings-form {
    background: white;
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow-medium);
    border: 2px solid var(--surface-color);
}

.settings-group {
    margin-bottom: 2rem;
    padding-bottom: 2rem;
    border-bottom: 1px solid var(--border-color);
}

.settings-group:last-child {
    border-bottom: none;
    margin-bottom: 0;
}

.group__title {
    font-size: 1.3rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

/* Footer */
.footer {
    background: var(--primary-color);
    color: white;
    text-align: center;
    padding: 2rem 0;
    margin-top: auto;
}

.footer__text {
    font-size: 0.9rem;
    opacity: 0.9;
}

.footer__link {
    color: var(--secondary-color);
    text-decoration: none;
    font-weight: 600;
}

.footer__link:hover {
    text-decoration: underline;
}

/* Loading overlay */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 9999;
}

.loading-spinner {
    background: white;
    padding: 2rem;
    border-radius: var(--border-radius);
    text-align: center;
    box-shadow: var(--shadow-heavy);
}

.spinner {
    width: 40px;
    height: 40px;
    border: 4px solid var(--border-color);
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 1rem;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Toast notifications */
.toast-container {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 1000;
    max-width: 400px;
}

.toast {
    background: white;
    border-radius: var(--border-radius);
    padding: 1rem 1.5rem;
    margin-bottom: 1rem;
    box-shadow: var(--shadow-medium);
    border-left: 4px solid var(--primary-color);
    animation: slideIn 0.3s ease-out;
}

.toast--success {
    border-left-color: #10B981;
}

.toast--error {
    border-left-color: var(--accent-color);
}

.toast--warning {
    border-left-color: #F59E0B;
}

.toast__title {
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.toast__message {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

@keyframes slideIn {
    from {
        transform: translateX(100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

/* Responsive design */
@media (max-width: 768px) {
    .container {
        padding: 0 0.5rem;
    }
    
    .header__title {
        font-size: 2rem;
    }
    
    .header__subtitle {
        font-size: 1rem;
    }
    
    .navigation__list {
        padding: 0.5rem 0;
    }
    
    .navigation__button {
        padding: 0.5rem 1rem;
        font-size: 0.9rem;
    }
    
    .timer-display {
        padding: 2rem 1rem;
    }
    
    .timer-display__time {
        font-size: 3rem;
    }
    
    .timer-controls {
        flex-direction: column;
        align-items: center;
    }
    
    .btn--large {
        width: 100%;
        max-width: 300px;
    }
    
    .contraction-form {
        padding: 1.5rem;
    }
    
    .form-actions {
        flex-direction: column;
        align-items: center;
    }
    
    .form-actions .btn {
        width: 100%;
        max-width: 300px;
    }
    
    .session__stats {
        grid-template-columns: 1fr;
    }
    
    .history-header {
        flex-direction: column;
        align-items: stretch;
    }
    
    .history-controls {
        justify-content: center;
    }
    
    .history-filters {
        flex-direction: column;
    }
    
    .history-item__header {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .history-item__details {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .analysis-summary {
        grid-template-columns: 1fr;
    }
    
    .summary-card {
        padding: 1.5rem;
    }
    
    .chart-container {
        padding: 1.5rem;
    }
    
    #contractions-chart {
        height: 300px;
    }
    
    .settings-form {
        padding: 1.5rem;
    }
    
    .toast-container {
        top: 10px;
        right: 10px;
        left: 10px;
        max-width: none;
    }
}

@media (max-width: 480px) {
    .header {
        padding: 1.5rem 0;
    }
    
    .header__title {
        font-size: 1.8rem;
    }
    
    .main {
        padding: 1rem 0;
    }
    
    .timer-display__time {
        font-size: 2.5rem;
    }
    
    .section__title {
        font-size: 1.5rem;
    }
    
    .history-item__details {
        grid-template-columns: 1fr;
    }
    
    .btn {
        padding: 0.75rem 1rem;
        font-size: 0.9rem;
    }
    
    .form-input,
    .form-select,
    .form-textarea {
        padding: 0.5rem;
    }
}

/* Print styles */
@media print {
    .navigation,
    .footer,
    .loading-overlay,
    .toast-container {
        display: none;
    }
    
    .header {
        background: none;
        color: var(--text-primary);
        box-shadow: none;
    }
    
    .main {
        padding: 0;
    }
    
    .tab-content {
        display: block !important;
    }
    
    .btn {
        display: none;
    }
    
    .history-item {
        break-inside: avoid;
    }
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    :root {
        --primary-color: #000080;
        --secondary-color: #4B0082;
        --text-primary: #000000;
        --text-secondary: #333333;
        --border-color: #000000;
    }
    
    .btn {
        border: 2px solid currentColor;
    }
    
    .form-input,
    .form-select,
    .form-textarea {
        border: 2px solid #000000;
    }
}

/* Reduced motion support */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    
    .spinner {
        animation: none;
    }
}