/* ============================================
   SNAPTARA - Photography Prompt Generator
   Apple-inspired Dark UI Design System
   ============================================ */

/* CSS Custom Properties */
:root {
    /* Colors - Dark Theme */
    --bg-primary: #0b0b0c;
    --bg-secondary: #141416;
    --bg-tertiary: #1c1c1e;
    --bg-card: rgba(28, 28, 30, 0.72);
    --bg-glass: rgba(28, 28, 30, 0.64);

    /* Text Colors */
    --text-primary: #f5f5f7;
    --text-secondary: #86868b;
    --text-tertiary: #6e6e73;

    /* Accent Colors */
    --accent-primary: #007aff;
    --accent-hover: #0a84ff;
    --accent-light: rgba(0, 122, 255, 0.16);

    /* Status Colors */
    --success: #30d158;
    --warning: #ffcc00;
    --error: #ff453a;

    /* Borders & Separators */
    --border-subtle: rgba(255, 255, 255, 0.08);
    --border-medium: rgba(255, 255, 255, 0.12);

    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.4);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.5);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.6);
    --shadow-glow: 0 0 40px rgba(0, 122, 255, 0.12);

    /* Spacing */
    --space-xs: 4px;
    --space-sm: 8px;
    --space-md: 16px;
    --space-lg: 24px;
    --space-xl: 32px;
    --space-2xl: 48px;

    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 20px;
    --radius-full: 9999px;

    /* Typography */
    --font-system: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    --font-size-xs: 11px;
    --font-size-sm: 13px;
    --font-size-base: 15px;
    --font-size-lg: 18px;
    --font-size-xl: 24px;
    --font-size-2xl: 32px;
    --font-size-3xl: 48px;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 400ms ease;

    /* Backdrop Blur */
    --blur-sm: 8px;
    --blur-md: 16px;
    --blur-lg: 24px;
}

/* Reset & Base */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: var(--font-size-base);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-system);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.5;
    min-height: 100vh;
    overflow-x: hidden;
}

/* App Container */
.app-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    min-height: 100vh;
    padding: var(--space-xl) var(--space-md);
    gap: var(--space-xl);
}

/* ============================================
   HEADER
   ============================================ */
.header {
    text-align: center;
    padding: var(--space-md) 0;
}

.app-title {
    font-size: var(--font-size-2xl);
    font-weight: 600;
    letter-spacing: -0.02em;
    background: linear-gradient(135deg, var(--text-primary) 0%, var(--text-secondary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.app-subtitle {
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
    margin-top: var(--space-xs);
    font-weight: 400;
}

/* ============================================
   MAIN CARD
   ============================================ */
.main-card {
    background: var(--bg-glass);
    backdrop-filter: blur(var(--blur-lg));
    -webkit-backdrop-filter: blur(var(--blur-lg));
    border: 1px solid var(--border-medium);
    border-radius: var(--radius-xl);
    padding: var(--space-2xl);
    max-width: 640px;
    width: 100%;
    box-shadow: var(--shadow-lg), var(--shadow-glow);
    position: relative;
    overflow: hidden;
}

/* Subtle gradient overlay */
.main-card::before {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(ellipse at top center, rgba(0, 122, 255, 0.06) 0%, transparent 70%);
    pointer-events: none;
}

/* Idea Display */
.idea-display {
    min-height: 160px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--space-xl);
    position: relative;
}

.idea-text {
    font-size: var(--font-size-xl);
    font-weight: 500;
    line-height: 1.4;
    text-align: center;
    color: var(--text-primary);
    transition: opacity var(--transition-base), transform var(--transition-base);
    max-width: 100%;
}

.idea-text.fade-out {
    opacity: 0;
    transform: translateY(8px);
    position: absolute;
}

.idea-text.fade-in {
    opacity: 1;
    transform: translateY(0);
    position: relative;
}

/* ============================================
   CATEGORY LOCKS
   ============================================ */
.categories {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-sm);
    justify-content: center;
    margin-bottom: var(--space-xl);
}

.category-group {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    background: var(--bg-tertiary);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-full);
    padding: var(--space-xs) var(--space-sm);
    transition: all var(--transition-fast);
}

.category-label {
    font-size: var(--font-size-xs);
    color: var(--text-secondary);
    font-weight: 500;
    text-transform: capitalize;
}

/* Lock Toggle Button */
.lock-toggle {
    background: none;
    border: none;
    padding: var(--space-xs);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
    color: var(--text-tertiary);
}

.lock-toggle:hover {
    background: var(--bg-secondary);
    color: var(--text-secondary);
}

.lock-toggle:focus-visible {
    outline: 2px solid var(--accent-primary);
    outline-offset: 2px;
}

.lock-toggle.locked {
    color: var(--accent-primary);
}

.lock-icon {
    width: 16px;
    height: 16px;
    transition: all var(--transition-fast);
}

.lock-icon.lock-open {
    opacity: 1;
}

.lock-icon.lock-closed {
    opacity: 0;
    position: absolute;
}

.lock-toggle.locked .lock-open {
    opacity: 0;
}

.lock-toggle.locked .lock-closed {
    opacity: 1;
}

/* ============================================
   ACTION BUTTONS
   ============================================ */
.actions {
    display: flex;
    gap: var(--space-md);
    justify-content: center;
    flex-wrap: wrap;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    padding: var(--space-md) var(--space-xl);
    border-radius: var(--radius-lg);
    font-size: var(--font-size-base);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    border: none;
    outline: none;
    text-decoration: none;
}

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

/* Primary Button */
.btn-primary {
    background: var(--accent-primary);
    color: white;
    box-shadow: 0 2px 8px rgba(0, 122, 255, 0.3);
}

.btn-primary:hover {
    background: var(--accent-hover);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(0, 122, 255, 0.4);
}

.btn-primary:active {
    transform: translateY(0);
}

/* Secondary Button */
.btn-secondary {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--border-medium);
}

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

/* Ghost Button */
.btn-ghost {
    background: transparent;
    color: var(--text-secondary);
    padding: var(--space-sm) var(--space-md);
    font-size: var(--font-size-sm);
}

.btn-ghost:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

/* Button Icons */
.btn-icon {
    width: 18px;
    height: 18px;
    flex-shrink: 0;
}

/* Loading Spinner */
.btn-loading .btn-icon {
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

/* ============================================
   TOAST NOTIFICATION
   ============================================ */
.toast {
    position: absolute;
    bottom: var(--space-xl);
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: var(--bg-tertiary);
    border: 1px solid var(--border-medium);
    border-radius: var(--radius-lg);
    padding: var(--space-md) var(--space-lg);
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    box-shadow: var(--shadow-lg);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
    z-index: 100;
}

.toast.show {
    transform: translateX(-50%) translateY(0);
    opacity: 1;
    visibility: visible;
}

.toast-icon {
    width: 18px;
    height: 18px;
    color: var(--success);
}

.toast span {
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--text-primary);
}

/* ============================================
   HISTORY SECTION
   ============================================ */
.history-section {
    max-width: 640px;
    width: 100%;
    background: var(--bg-glass);
    backdrop-filter: blur(var(--blur-md));
    -webkit-backdrop-filter: blur(var(--blur-md));
    border: 1px solid var(--border-medium);
    border-radius: var(--radius-xl);
    padding: var(--space-xl);
}

.history-title {
    font-size: var(--font-size-base);
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: var(--space-lg);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.history-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
}

.history-item {
    background: var(--bg-tertiary);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-md);
    padding: var(--space-md);
    transition: all var(--transition-fast);
    animation: slideIn var(--transition-base) ease;
}

.history-item:hover {
    border-color: var(--border-medium);
}

.history-item-text {
    font-size: var(--font-size-sm);
    color: var(--text-primary);
    line-height: 1.5;
    margin-bottom: var(--space-sm);
}

.history-item-meta {
    font-size: var(--font-size-xs);
    color: var(--text-tertiary);
}

.history-empty {
    text-align: center;
    color: var(--text-tertiary);
    font-size: var(--font-size-sm);
    padding: var(--space-xl) 0;
}

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

/* ============================================
   KEYBOARD HINTS
   ============================================ */
.keyboard-hints {
    display: flex;
    gap: var(--space-lg);
    padding: var(--space-md);
}

.hint {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    font-size: var(--font-size-xs);
    color: var(--text-tertiary);
}

kbd {
    display: inline-block;
    padding: 2px 8px;
    font-family: var(--font-system);
    font-size: var(--font-size-xs);
    color: var(--text-secondary);
    background: var(--bg-tertiary);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-sm);
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.3);
}

/* ============================================
   RESPONSIVE DESIGN
   ============================================ */
@media (max-width: 768px) {
    :root {
        --font-size-xl: 20px;
        --font-size-2xl: 28px;
        --font-size-3xl: 36px;
    }

    .app-container {
        padding: var(--space-lg) var(--space-md);
        gap: var(--space-lg);
    }

    .main-card {
        padding: var(--space-xl);
        border-radius: var(--radius-lg);
    }

    .idea-display {
        min-height: 120px;
    }

    .categories {
        gap: var(--space-xs);
    }

    .category-group {
        padding: var(--space-xs);
    }

    .category-label {
        font-size: 10px;
    }

    .btn {
        padding: var(--space-md) var(--space-lg);
        font-size: var(--font-size-sm);
    }

    .actions {
        flex-direction: column;
        gap: var(--space-sm);
    }

    .btn-primary,
    .btn-secondary {
        width: 100%;
    }

    .keyboard-hints {
        flex-direction: column;
        gap: var(--space-sm);
        align-items: center;
    }

    .history-section {
        padding: var(--space-lg);
    }
}

@media (max-width: 480px) {
    :root {
        --font-size-xl: 18px;
        --font-size-2xl: 24px;
    }

    .main-card {
        padding: var(--space-lg);
    }

    .categories {
        justify-content: flex-start;
        overflow-x: auto;
        flex-wrap: nowrap;
        padding-bottom: var(--space-sm);
        -webkit-overflow-scrolling: touch;
    }

    .category-group {
        flex-shrink: 0;
    }
}

/* ============================================
   ACCESSIBILITY
   ============================================ */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* High contrast mode */
@media (prefers-contrast: high) {
    :root {
        --border-subtle: rgba(255, 255, 255, 0.2);
        --border-medium: rgba(255, 255, 255, 0.3);
    }
}

/* Focus visible polyfill support */
.focus-visible .lock-toggle:focus {
    outline: none;
}

.lock-toggle.focus-visible:focus {
    outline: 2px solid var(--accent-primary);
    outline-offset: 2px;
}