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

:root {
    /* Light Theme Colors */
    --color-primary: #E4C1F9;
    --color-secondary: #F6DFEB;
    --color-accent: #D0F4DE;
    --color-warning: #FCF6BD;
    --color-danger: #FFB7C5;
    
    /* Light Theme UI Colors */
    --color-background: #ffffff;
    --color-surface: #fafafa;
    --color-text-primary: #2d2d2d;
    --color-text-secondary: #666666;
    --color-border: #e0e0e0;
    --color-shadow: rgba(0, 0, 0, 0.1);
    
    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 2rem;
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    
    /* Border Radius */
    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    
    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
}

/* Dark Theme */
[data-theme="dark"] {
    --color-background: #1a1a1a;
    --color-surface: #2d2d2d;
    --color-text-primary: #ffffff;
    --color-text-secondary: #cccccc;
    --color-border: #404040;
    --color-shadow: rgba(0, 0, 0, 0.3);
}

/* Base Styles */
html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--color-text-primary);
    background-color: var(--color-background);
    transition: background-color var(--transition-normal), color var(--transition-normal);
}

/* Layout Components */
.app {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.main {
    flex: 1;
}

/* Header */
.header {
    background-color: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    padding: var(--spacing-lg) 0;
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
}

.header__container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.header__title {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    color: var(--color-text-primary);
    margin: 0;
}

/* Theme Toggle */
.theme-toggle {
    background: var(--color-primary);
    border: none;
    border-radius: var(--radius-lg);
    padding: var(--spacing-sm) var(--spacing-md);
    cursor: pointer;
    transition: all var(--transition-normal);
    font-size: var(--font-size-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    min-width: 48px;
    min-height: 48px;
}

.theme-toggle:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px var(--color-shadow);
}

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

/* Sections */
.countdown-creator {
    padding: var(--spacing-2xl) 0;
    background: linear-gradient(135deg, var(--color-secondary), var(--color-accent));
}

.countdowns-list {
    padding: var(--spacing-2xl) 0;
}

.faq {
    padding: var(--spacing-2xl) 0;
    background-color: var(--color-surface);
}

.section-title {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    text-align: center;
    margin-bottom: var(--spacing-2xl);
    color: var(--color-text-primary);
}

/* Forms */
.countdown-form {
    background: var(--color-background);
    padding: var(--spacing-xl);
    border-radius: var(--radius-xl);
    box-shadow: 0 8px 32px var(--color-shadow);
    max-width: 500px;
    margin: 0 auto;
}

.form-group {
    margin-bottom: var(--spacing-lg);
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-md);
}

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

.form-input {
    width: 100%;
    padding: var(--spacing-md);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    font-size: var(--font-size-base);
    background-color: var(--color-background);
    color: var(--color-text-primary);
    transition: all var(--transition-normal);
}

.form-input:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(228, 193, 249, 0.1);
}

.form-input:invalid {
    border-color: var(--color-danger);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-md) var(--spacing-lg);
    border: none;
    border-radius: var(--radius-md);
    font-size: var(--font-size-base);
    font-weight: 600;
    text-decoration: none;
    cursor: pointer;
    transition: all var(--transition-normal);
    min-height: 48px;
    gap: var(--spacing-sm);
}

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

.btn--primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px var(--color-shadow);
}

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

.btn--danger:hover {
    background: #ff9db3;
    transform: translateY(-2px);
}

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

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

/* Countdown Cards */
.countdowns-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-xl);
}

.countdown-card {
    background: var(--color-surface);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    box-shadow: 0 4px 20px var(--color-shadow);
    transition: all var(--transition-normal);
    border: 1px solid var(--color-border);
}

.countdown-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 40px var(--color-shadow);
}

.countdown-card__header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: var(--spacing-lg);
}

.countdown-card__title {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--color-text-primary);
    margin: 0;
    word-break: break-word;
}

.countdown-card__delete {
    background: none;
    border: none;
    color: var(--color-danger);
    cursor: pointer;
    font-size: var(--font-size-lg);
    padding: var(--spacing-xs);
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
    min-width: 32px;
    min-height: 32px;
}

.countdown-card__delete:hover {
    background: var(--color-danger);
    color: white;
}

.countdown-card__date {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-lg);
}

.countdown-display {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-lg);
}

.countdown-unit {
    text-align: center;
    padding: var(--spacing-md);
    background: var(--color-background);
    border-radius: var(--radius-md);
    border: 1px solid var(--color-border);
}

.countdown-unit__value {
    display: block;
    font-size: var(--font-size-2xl);
    font-weight: 700;
    color: var(--color-primary);
    line-height: 1;
}

.countdown-unit__label {
    display: block;
    font-size: var(--font-size-xs);
    color: var(--color-text-secondary);
    text-transform: uppercase;
    font-weight: 600;
    margin-top: var(--spacing-xs);
}

.countdown-card--expired {
    background: linear-gradient(135deg, var(--color-danger), var(--color-warning));
    animation: pulse 2s infinite;
}

.countdown-card--expired .countdown-unit__value {
    color: var(--color-text-primary);
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.8; }
}

/* FAQ */
.faq-list {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    background: var(--color-background);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-md);
    overflow: hidden;
}

.faq-question {
    padding: var(--spacing-lg);
    font-weight: 600;
    cursor: pointer;
    background: var(--color-surface);
    transition: background-color var(--transition-fast);
    list-style: none;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.faq-question:hover {
    background: var(--color-primary);
}

.faq-question::after {
    content: '+';
    font-size: var(--font-size-xl);
    font-weight: bold;
    transition: transform var(--transition-fast);
}

.faq-item[open] .faq-question::after {
    transform: rotate(45deg);
}

.faq-answer {
    padding: 0 var(--spacing-lg) var(--spacing-lg);
}

.faq-answer p {
    color: var(--color-text-secondary);
    line-height: 1.6;
}

/* Modal */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-normal);
}

.modal--active {
    opacity: 1;
    visibility: visible;
}

.modal__content {
    background: var(--color-background);
    border-radius: var(--radius-xl);
    padding: var(--spacing-2xl);
    max-width: 400px;
    width: 90%;
    text-align: center;
    transform: scale(0.8);
    transition: transform var(--transition-normal);
}

.modal--active .modal__content {
    transform: scale(1);
}

.modal__title {
    font-size: var(--font-size-2xl);
    margin-bottom: var(--spacing-md);
    color: var(--color-text-primary);
}

.modal__message {
    font-size: var(--font-size-lg);
    margin-bottom: var(--spacing-xl);
    color: var(--color-text-secondary);
}

/* Footer */
.footer {
    background: var(--color-surface);
    border-top: 1px solid var(--color-border);
    padding: var(--spacing-xl) 0;
    margin-top: auto;
}

.footer__text {
    text-align: center;
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
}

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

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

/* Empty State */
.empty-state {
    text-align: center;
    padding: var(--spacing-2xl);
    color: var(--color-text-secondary);
}

.empty-state__icon {
    font-size: 4rem;
    margin-bottom: var(--spacing-lg);
    opacity: 0.5;
}

.empty-state__title {
    font-size: var(--font-size-xl);
    margin-bottom: var(--spacing-md);
    color: var(--color-text-primary);
}

.empty-state__message {
    font-size: var(--font-size-base);
    max-width: 400px;
    margin: 0 auto;
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 0 var(--spacing-sm);
    }
    
    .header__title {
        font-size: var(--font-size-xl);
    }
    
    .section-title {
        font-size: var(--font-size-2xl);
    }
    
    .countdown-form {
        padding: var(--spacing-lg);
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .countdowns-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }
    
    .countdown-display {
        grid-template-columns: repeat(2, 1fr);
        gap: var(--spacing-xs);
    }
    
    .countdown-unit {
        padding: var(--spacing-sm);
    }
    
    .countdown-unit__value {
        font-size: var(--font-size-xl);
    }
    
    .modal__content {
        padding: var(--spacing-xl);
    }
}

@media (max-width: 480px) {
    .header__container {
        padding: 0 var(--spacing-sm);
    }
    
    .header__title {
        font-size: var(--font-size-lg);
    }
    
    .countdown-creator,
    .countdowns-list,
    .faq {
        padding: var(--spacing-xl) 0;
    }
    
    .countdown-display {
        grid-template-columns: repeat(4, 1fr);
    }
    
    .countdown-unit__value {
        font-size: var(--font-size-lg);
    }
    
    .countdown-unit__label {
        font-size: 0.625rem;
    }
}

/* Print Styles */
@media print {
    .header,
    .footer,
    .theme-toggle,
    .countdown-creator,
    .faq {
        display: none;
    }
    
    .countdown-card {
        break-inside: avoid;
        box-shadow: none;
        border: 1px solid #ccc;
    }
}

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

/* High Contrast Mode */
@media (prefers-contrast: high) {
    :root {
        --color-border: #000000;
        --color-shadow: rgba(0, 0, 0, 0.5);
    }
    
    .btn {
        border: 2px solid currentColor;
    }
}