/* Design System Variables */
:root {
    /* Colors */
    --color-primary: #2563eb;
    --color-primary-dark: #1d4ed8;
    --color-accent: #7c3aed;
    --color-white: #ffffff;
    --color-light-gray: #f3f4f6;
    --color-medium-gray: #e5e7eb;
    --color-dark-gray: #6b7280;
    --color-black: #111827;
    --color-success: #10b981;
    --color-warning: #f59e0b;
    --color-error: #ef4444;
    --color-info: #3b82f6;

    /* Typography */
    --font-primary: Inter, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
    
    /* Font Sizes */
    --text-xs: 0.75rem;
    --text-sm: 0.875rem;
    --text-base: 1rem;
    --text-lg: 1.125rem;
    --text-xl: 1.25rem;
    --text-2xl: 1.5rem;
    --text-3xl: 1.875rem;

    /* 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: 0.125rem;
    --radius-md: 0.375rem;
    --radius-lg: 0.5rem;
    --radius-xl: 1rem;
    --radius-full: 9999px;

    /* Shadows */
    /* Use --shadow-rgb defined in themes.css for themeable shadow colors */
    --shadow-sm: 0 1px 2px 0 rgba(var(--shadow-rgb), 0.05);
    --shadow-md: 0 4px 6px -1px rgba(var(--shadow-rgb), 0.1), 0 2px 4px -2px rgba(var(--shadow-rgb), 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(var(--shadow-rgb), 0.1), 0 4px 6px -4px rgba(var(--shadow-rgb), 0.1);

    /* Transitions */
    --transition-fast: 0.15s ease-in-out;
    --transition-default: 0.2s ease-in-out;
    --transition-slow: 0.3s ease-in-out;
}

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

body {
    font-family: var(--font-primary);
    line-height: 1.6;
    color: var(--color-black);
    background-color: var(--color-light-gray);
    font-size: var(--text-base);
}

/* Layout */
.app-container {
    display: flex;
    min-height: 100vh;
    max-width: 1400px;
    margin: 0 auto;
    background-color: var(--color-white);
    box-shadow: var(--shadow-lg);
}

/* Sidebar */
.sidebar {
    width: 280px;
    background-color: var(--color-white);
    padding: var(--spacing-lg);
    border-right: 1px solid var(--color-medium-gray);
}

.logo {
    font-size: var(--text-2xl);
    font-weight: 600;
    color: var(--color-primary);
    margin-bottom: var(--spacing-lg);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.nav-tabs {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.nav-tab {
    padding: var(--spacing-md);
    border: none;
    background: none;
    text-align: left;
    cursor: pointer;
    border-radius: var(--radius-md);
    font-weight: 500;
    color: var(--color-dark-gray);
    transition: all var(--transition-default);
}

.nav-tab:hover {
    background-color: var(--color-light-gray);
    color: var(--color-primary);
}

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

/* Content Area */
.content {
    flex: 1;
    padding: var(--spacing-xl);
    overflow-y: auto;
    background-color: var(--color-light-gray);
}

.tab-content {
    display: none;
    animation: fadeIn var(--transition-default);
}

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

/* Content View Header (replaces .decks-header) */
.content-view-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-bottom: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
    border-bottom: 1px solid var(--border-primary);
}

.view-title {
    font-size: var(--text-3xl);
    font-weight: 700;
    color: var(--text-primary);
}

/* Deck Quick Access Area */
.deck-quick-access-area {
    display: flex;
    align-items: center;
    justify-content: space-between; /* Pushes button to the right if stats are grouped */
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
    background-color: var(--bg-primary);
    border: 1px solid var(--border-primary);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
}

.quick-stat {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 0 var(--spacing-lg);
}

.quick-stat .stat-value {
    font-size: var(--text-2xl);
    font-weight: 600;
    color: var(--text-primary);
}

.quick-stat .stat-label {
    font-size: var(--text-xs);
    color: var(--text-secondary);
    text-transform: uppercase;
}

#study-all-due-btn {
    margin-left: auto; /* Pushes button to the far right */
}

/* Deck Grid */
.decks-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: var(--spacing-lg);
}

/* Old .deck-card styles - to be replaced by .deck-card-revamped */
/*.deck-card {
    background: var(--color-white);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-default);
    border: 1px solid var(--color-medium-gray);
}

.deck-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.deck-card h3 {
    font-size: var(--text-xl);
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--color-black);
}

.deck-stats {
    display: flex;
    gap: var(--spacing-md);
    margin: var(--spacing-md) 0;
    font-size: var(--text-sm);
    color: var(--color-dark-gray);
}

.deck-actions {
    display: flex;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-md);
}*/

/* New Revamped Deck Card Styles */
.deck-card-revamped {
    background-color: var(--card-bg);
    border: 1px solid var(--border-primary);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    display: flex;
    flex-direction: column;
    justify-content: space-between; /* Pushes stats/actions to bottom */
    transition: all var(--transition-default);
    box-shadow: var(--shadow-md);
    min-height: 220px; /* Ensure a decent minimum height */
}

.deck-card-revamped:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
    border-color: var(--card-hover-border);
}

.deck-card-main-info {
    margin-bottom: var(--spacing-md);
}

.deck-card-title {
    font-size: var(--text-xl);
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-xs);
}

.deck-card-description {
    font-size: var(--text-sm);
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    line-height: 1.4;
    /* Potentially limit lines with text-overflow if desired */
    display: -webkit-box;
    -webkit-line-clamp: 3; /* Show up to 3 lines */
    -webkit-box-orient: vertical;  
    overflow: hidden;
    text-overflow: ellipsis;
    min-height: calc(var(--text-sm) * 1.4 * 1); /* Min height for 1 line to prevent collapse */
}

.deck-card-stats-actions {
    margin-top: auto; /* Pushes this block to the bottom if card grows */
}

.deck-card-stats {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: var(--text-sm);
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    padding-top: var(--spacing-sm);
    border-top: 1px solid var(--border-secondary);
}

.deck-card-stats .stat-due-cards {
    font-weight: 600;
    color: var(--color-accent); /* Make due cards stand out */
}

.deck-card-actions {
    display: grid;
    grid-template-columns: repeat(2, 1fr); /* 2x2 grid for buttons */
    gap: var(--spacing-sm);
}

.deck-card-actions .btn {
    padding: var(--spacing-sm) var(--spacing-xs); /* Adjust padding if needed */
    font-size: var(--text-xs); /* Slightly smaller text for buttons */
    text-align: center;
    display: flex;
    align-items: center;
    justify-content: center;
}

.deck-card-actions .btn .icon {
    margin-right: var(--spacing-xs); /* Ensure consistent icon spacing */
}

/* Study Area */
.study-area {
    max-width: 800px;
    margin: 0 auto;
    padding: var(--spacing-xl);
}

.study-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.study-stats {
    display: flex;
    justify-content: center;
    gap: var(--spacing-xl);
    margin-top: var(--spacing-md);
    color: var(--color-dark-gray);
}

.card-container {
    perspective: 1000px;
    margin: var(--spacing-2xl) 0;
}

.card {
    width: 100%;
    height: 400px;
    position: relative;
    transform-style: preserve-3d;
    transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.card.flipped {
    transform: rotateY(180deg);
}

.card-inner {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-xl);
    background: var(--color-white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--color-medium-gray);
}

.card-back {
    transform: rotateY(180deg);
}

.card-controls {
    display: flex;
    justify-content: center;
    gap: var(--spacing-md);
    margin-top: var(--spacing-xl);
}

/* Buttons */
.btn {
    padding: var(--spacing-sm) var(--spacing-md);
    border: none;
    border-radius: var(--radius-md);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-default);
    font-size: var(--text-sm);
}

.btn:hover {
    transform: translateY(-1px);
}

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

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

/* Modals */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
    align-items: center;
    justify-content: center;
    z-index: 1000;
}

.modal.active {
    display: flex;
    animation: fadeIn var(--transition-default);
}

.modal-content {
    background: var(--color-white);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    width: 90%;
    max-width: 500px;
    box-shadow: var(--shadow-lg);
}

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

.form-group label {
    display: block;
    margin-bottom: var(--spacing-xs);
    font-weight: 500;
    color: var(--color-dark-gray);
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    border: 1px solid var(--color-medium-gray);
    border-radius: var(--radius-md);
    font-size: var(--text-base);
    transition: all var(--transition-default);
}

.form-group input:focus,
.form-group textarea:focus {
    border-color: var(--color-primary);
    outline: none;
    box-shadow: 0 0 0 2px rgba(37, 99, 235, 0.1);
}

.modal-actions {
    display: flex;
    justify-content: flex-end;
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
}

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

/* Responsive Design */
@media (max-width: 1024px) {
    .app-container {
        flex-direction: column;
    }

    .sidebar {
        width: 100%;
        border-right: none;
        border-bottom: 1px solid var(--color-medium-gray);
    }

    .nav-tabs {
        flex-direction: row;
        overflow-x: auto;
        padding-bottom: var(--spacing-sm);
    }

    .nav-tab {
        white-space: nowrap;
    }

    .content {
        padding: var(--spacing-lg);
    }

    .study-area {
        padding: var(--spacing-md);
    }

    .card {
        height: 300px;
    }
}

@media (max-width: 640px) {
    .decks-header {
        flex-direction: column;
        gap: var(--spacing-md);
        align-items: stretch;
    }

    .deck-actions {
        flex-direction: column;
    }

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

    .btn {
        width: 100%;
    }
}

/* Settings Section */
.settings-section {
    background: var(--color-white);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
    border: 1px solid var(--color-medium-gray);
}

.settings-section h3 {
    font-size: var(--text-lg);
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    color: var(--color-black);
}

/* Form Elements */
select {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    border: 1px solid var(--color-medium-gray);
    border-radius: var(--radius-md);
    font-size: var(--text-base);
    background-color: var(--color-white);
    color: var(--color-black);
    cursor: pointer;
    transition: all var(--transition-default);
}

select:focus {
    border-color: var(--color-primary);
    outline: none;
    box-shadow: 0 0 0 2px rgba(37, 99, 235, 0.1);
}

/* Card Image */
.card-image {
    max-width: 100%;
    height: auto;
    border-radius: var(--radius-md);
    margin-top: var(--spacing-md);
}

/* Deck Form */
#deck-form {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

#deck-form input,
#deck-form textarea {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    border: 1px solid var(--color-medium-gray);
    border-radius: var(--radius-md);
    font-size: var(--text-base);
    transition: all var(--transition-default);
}

#deck-form input:focus,
#deck-form textarea:focus {
    border-color: var(--color-primary);
    outline: none;
    box-shadow: 0 0 0 2px rgba(37, 99, 235, 0.1);
}

#deck-form textarea {
    min-height: 100px;
    resize: vertical;
}

/* Modal Close Button */
.modal-close {
    position: absolute;
    top: var(--spacing-lg);
    right: var(--spacing-lg);
    background: transparent;
    border: none;
    font-size: 2rem;
    color: var(--color-dark-gray);
    cursor: pointer;
    line-height: 1;
    z-index: 10;
    padding: 0;
    transition: color var(--transition-default), background var(--transition-default);
}

.modal-close:hover,
.modal-close:focus {
    color: var(--color-primary);
    background: var(--color-light-gray);
    outline: none;
    border-radius: var(--radius-full);
}

.form-error {
    color: var(--color-error);
    font-size: var(--text-sm);
    margin-top: var(--spacing-xs);
    margin-bottom: var(--spacing-xs);
    min-height: 1.2em;
    transition: opacity var(--transition-default);
}

/* Deck Details Modal Specifics */
.deck-details-modal .modal-content {
    max-width: 700px; /* Wider for card list */
}

.deck-details-card-list {
    list-style-type: none;
    padding: 0;
    margin: var(--spacing-md) 0;
    max-height: 60vh; /* Allow scrolling for long lists */
    overflow-y: auto;
}

.deck-details-card-list li {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-md);
    border: 1px solid var(--border-primary);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-sm);
    background-color: var(--bg-primary);
}

.deck-details-card-list li .card-info p {
    margin: 0 0 var(--spacing-xs) 0;
    font-size: var(--text-sm);
}

.deck-details-card-list li .card-info p strong {
    font-weight: 500;
}

.deck-details-card-list li .card-actions .btn {
    padding: var(--spacing-xs) var(--spacing-sm); /* Slightly smaller buttons in list */
}

/* Rating Controls for Study Area */
.rating-controls {
    display: none; /* Initially hidden */
    justify-content: center;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-md);
}

.rating-controls .btn {
    flex-grow: 1; /* Make buttons share space */
    max-width: 150px; /* Prevent them from becoming too wide */
}

/* Specific styles for rating buttons */
.rating-controls .rating-again {
    background-color: var(--color-error);
    color: var(--color-white); /* Ensure contrast */
}
.rating-controls .rating-again:hover {
    background-color: var(--color-error); /* Darken or adjust on hover if needed */
    filter: brightness(0.9);
}

.rating-controls .rating-hard {
    background-color: var(--color-warning);
    color: var(--color-black); /* Warning color is light, needs dark text */
}
.rating-controls .rating-hard:hover {
    background-color: var(--color-warning);
    filter: brightness(0.9);
}

.rating-controls .rating-good {
    background-color: var(--color-info); /* Using info for a neutral/positive */
    color: var(--color-white);
}
.rating-controls .rating-good:hover {
    background-color: var(--color-info);
    filter: brightness(0.9);
}

.rating-controls .rating-easy {
    background-color: var(--color-success);
    color: var(--color-white);
}
.rating-controls .rating-easy:hover {
    background-color: var(--color-success);
    filter: brightness(0.9);
}

/* Toast Notifications */
#toast-container {
    position: fixed;
    top: var(--spacing-lg);
    right: var(--spacing-lg);
    z-index: 2000; /* Above modals */
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.toast {
    background-color: var(--color-black);
    color: var(--color-white);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    opacity: 0;
    transform: translateX(100%);
    animation: toast-slide-in 0.5s forwards, toast-fade-out 0.5s 2.5s forwards; /* Slide in, then fade out after 2.5s delay */
    min-width: 250px;
    max-width: 350px;
}

.toast.success {
    background-color: var(--color-success);
}

.toast.error {
    background-color: var(--color-error);
}

.toast.info {
    background-color: var(--color-info);
}

@keyframes toast-slide-in {
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes toast-fade-out {
    from {
        opacity: 1;
    }
    to {
        opacity: 0;
        transform: translateY(-20px); /* Optional: move up slightly on fade out */
    }
}

/* Bulk Import Template Preview Area */
.bulk-import-preview {
    background-color: var(--bg-secondary); /* Use a themed background */
    color: var(--text-primary);          /* Use themed text color */
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    overflow-x: auto;
    border: 1px solid var(--border-primary); /* Add a subtle border */
    font-family: var(--font-mono);
    font-size: var(--text-sm);
}

/* Bulk Add Helper Text */
#bulk-add-helper {
    font-size: 0.9em;
    color: var(--text-secondary); /* Use themed secondary text color */
    margin-bottom: var(--spacing-sm);
}

#bulk-add-helper code {
    background-color: var(--bg-tertiary);
    color: var(--text-primary);
    padding: 0.1em 0.4em;
    border-radius: var(--radius-sm);
    font-size: 0.95em;
}

/* SVG Icons */
.icon {
    display: inline-block;
    width: 1em; /* Adjust size relative to font-size of parent */
    height: 1em;
    vertical-align: -0.125em; /* Adjust for better alignment with text */
    fill: currentColor; /* Inherit color from parent text */
}

.btn .icon {
    margin-right: var(--spacing-xs); /* Space between icon and text in a button */
}

.btn .icon-only {
    margin-right: 0;
}