/* ================================================
   COURSE DISCOVERY: A REFINED & UNIFIED UI SYSTEM
   ================================================ */

/* --- Core Design Tokens --- */
:root {
    --space-1: 4px;
    --space-2: 8px;
    --space-3: 12px;
    --space-4: 16px;
    --space-5: 24px;
    --radius-sm: 6px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-full: 999px;
    --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* --- Page Header --- */
.page-header {
    background: var(--bg-secondary);
    padding: var(--space-5) 0;
    border-bottom: 1px solid var(--border-color);
}

.page-header .container {
    padding: 0 var(--space-5);
    max-width: 1200px;
    margin: 0 auto;
}

.page-title {
    font-size: clamp(2rem, 5vw, 2.75rem);
    font-weight: 800;
    line-height: 1.2;
    margin: 0 0 var(--space-2);
    color: var(--text-primary);
}

.page-subtitle {
    font-size: 1.125rem;
    color: var(--text-muted);
    margin: 0;
    max-width: 70ch;
}

/* --- Filter Bar --- */
.filter-bar {
    padding: var(--space-5) 0;
    border-bottom: 1px solid var(--border-color);
}

.filter-controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--space-4);
}

.results-count {
    font-size: 1rem;
    color: var(--text-muted);
}

.results-count span {
    font-weight: 700;
    color: var(--text-primary);
}

.filter-buttons {
    display: flex;
    gap: var(--space-3);
    flex-wrap: wrap;
}

.filter-btn {
    padding: var(--space-2) var(--space-4);
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-full);
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-primary);
    cursor: pointer;
    text-decoration: none;
}

.filter-btn:hover {
    border-color: var(--brand);
    background: var(--surface-hover);
}

.filter-btn.active {
    background: var(--brand);
    color: var(--text-inverse);
    border-color: var(--brand);
}

/* --- The Definitive Course Card --- */
.course-card {
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    height: 100%;
    display: flex;
    flex-direction: column;
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.02);
    transition: transform var(--transition-base), box-shadow var(--transition-base), border-color var(--transition-base);
}

.course-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    border-color: var(--brand);
}

.course-link {
    text-decoration: none;
    color: inherit;
}

.course-thumbnail {
    position: relative;
    aspect-ratio: 16 / 9;
    overflow: hidden;
    background: var(--surface);
    border-top-left-radius: var(--radius-md);
    border-top-right-radius: var(--radius-md);
}

.course-thumbnail img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 400ms ease;
}

.course-card:hover .course-thumbnail img {
    transform: scale(1.05);
}

.course-wishlist-btn {
    position: absolute;
    top: var(--space-3);
    right: var(--space-3);
    z-index: 2;
    width: 36px;
    height: 36px;
    border-radius: var(--radius-full);
    background: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(6px);
    border: 1px solid var(--border-color);
    display: grid;
    place-items: center;
    cursor: pointer;
    color: var(--text-secondary);
    box-shadow: var(--shadow-sm);
    opacity: 0;
    transform: translateY(4px);
    transition: opacity var(--transition-base), transform var(--transition-base), background-color var(--transition-base), color var(--transition-base), border-color var(--transition-base);
}

/* Ensure the heart icon respects the --ui-icon-size variable */
.course-wishlist-btn svg,
.course-wishlist-btn i.bi {
    width: var(--ui-icon-size, 22px);
    height: var(--ui-icon-size, 22px);
    font-size: var(--ui-icon-size, 22px);
}

.course-wishlist-btn .heart-icon {
    stroke-width: 2.4;
    color: #fff;
}

.course-card:hover .course-wishlist-btn {
    opacity: 1;
    transform: translateY(0);
}

.course-wishlist-btn:hover {
    background: #fff;
}

.course-wishlist-btn[data-bookmarked="true"] {
    color: var(--error);
}

.course-wishlist-btn[data-bookmarked="true"] svg {
    fill: var(--error);
}

[data-theme="dark"] .course-wishlist-btn {
    background: rgba(30, 30, 40, 0.85);
}

[data-theme="dark"] .course-wishlist-btn:hover {
    background: var(--bg-elevated);
}

/* Accessible focus treatment */
.course-wishlist-btn:focus-visible {
    outline: 2px solid var(--brand, #0cc0df);
    outline-offset: 2px;
    box-shadow: none;
}

/* Optimistic UI state: keep subtle */
.course-wishlist-btn.optimistic {
    opacity: 0.92;
}

/* Subtle heart feedback on toggle */
@keyframes heart-bounce {
    0% {
        transform: translateY(0) scale(1);
    }

    50% {
        transform: translateY(0) scale(1.03);
    }

    100% {
        transform: translateY(0) scale(1);
    }
}

.course-wishlist-btn.animating {
    animation: heart-bounce 220ms ease-out;
}

/* Error feedback: very gentle shake */
@keyframes heart-shake {
    0% {
        transform: translateX(0);
    }

    25% {
        transform: translateX(-2px);
    }

    50% {
        transform: translateX(2px);
    }

    75% {
        transform: translateX(-1px);
    }

    100% {
        transform: translateX(0);
    }
}

.course-wishlist-btn.shake {
    animation: heart-shake 320ms ease-in-out;
}

/* Respect reduced motion preferences */
@media (prefers-reduced-motion: reduce) {

    .course-wishlist-btn.animating,
    .course-wishlist-btn.shake {
        animation: none;
    }
}

.course-body {
    padding: var(--space-4);
    display: flex;
    flex-direction: column;
    flex: 1;
    gap: var(--space-3);
}

.course-title {
    font-size: 1rem;
    font-weight: 700;
    color: var(--text-primary);
    margin: 0;
    line-height: 1.4;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.course-author {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    font-size: 0.8rem;
    color: var(--text-muted);
}

.author-avatar {
    width: 24px;
    height: 24px;
    border-radius: var(--radius-full);
    object-fit: cover;
    background: var(--surface);
}

.course-rating-meta {
    display: flex;
    align-items: center;
    gap: var(--space-2);
}

.course-rating-value {
    font-size: 0.9rem;
    font-weight: 700;
    color: var(--rating-text, #b45309);
}

[data-theme="dark"] .course-rating-value {
    color: var(--rating-text, #f59e0b);
}

.course-rating-stars {
    display: flex;
    color: var(--rating-color, #f59e0b);
}

.course-rating-count {
    font-size: 0.8rem;
    color: var(--text-muted);
}

.course-footer {
    margin-top: auto;
    padding: 0 var(--space-4) var(--space-4);
    display: flex;
    flex-direction: column;
    gap: var(--space-3);
}

.course-price-info {
    padding-top: var(--space-3);
    border-top: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    width: 100%;
}

.course-price {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
}

.course-category {
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.course-cart-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-3);
    width: 100%;
    padding: var(--space-3);
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
    background: var(--bg-primary);
    color: var(--text-primary);
    font-weight: 600;
    cursor: pointer;
}

.course-cart-btn:hover {
    background: var(--surface-hover);
    border-color: var(--brand);
}

.course-cart-btn.in-cart {
    background: var(--brand);
    color: var(--text-inverse);
    border-color: var(--brand);
}

.course-cart-btn .icon-check,
.course-cart-btn.in-cart .icon-cart,
.course-cart-btn .label-added,
.course-cart-btn.in-cart .label-add,
.course-cart-btn .spinner {
    display: none;
}

.course-cart-btn.in-cart .icon-check,
.course-cart-btn.in-cart .label-added {
    display: inline-block;
}

.course-cart-btn.processing .spinner {
    display: inline-block;
    animation: spin 1s linear infinite;
}

.course-cart-btn.processing .icon {
    display: none;
}

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

/* --- Grid Layout for Cards --- */
.courses-grid {
    display: grid;
    gap: var(--space-5);
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
}

/* ================================================
   DEGREETRACK CARD: A REFINED COMPANION COMPONENT
   ================================================ */

.degree-track-card {
    position: relative;
    height: 100%;
    display: flex;
    overflow: hidden;
    border-radius: var(--radius-md);
    background: var(--surface);
    border: 1px solid var(--border-color);
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.02);
    transition: transform var(--transition-base), box-shadow var(--transition-base), border-color var(--transition-base);
}

.degree-track-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    border-color: var(--brand);
}

.track-link {
    display: block;
    width: 100%;
    height: 100%;
    text-decoration: none;
    color: inherit;
}

.track-media-container {
    position: absolute;
    inset: 0;
    z-index: 1;
}

.track-media {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 400ms ease;
}

.degree-track-card:hover .track-media {
    transform: scale(1.05);
}

.track-media-overlay {
    position: absolute;
    inset: 0;
    background: linear-gradient(to top, rgba(0, 0, 0, 0.85) 0%, rgba(0, 0, 0, 0.4) 30%, transparent 60%);
    transition: background-color var(--transition-base);
}

.degree-track-card:hover .track-media-overlay {
    background: linear-gradient(to top, rgba(0, 0, 0, 0.95) 0%, rgba(0, 0, 0, 0.5) 40%, transparent 70%);
}

.track-content {
    position: relative;
    z-index: 2;
    color: var(--text-inverse);
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
    height: 100%;
    text-shadow: 0 1px 4px rgba(0, 0, 0, 0.5);
}

.track-title {
    font-size: 1.25rem;
    font-weight: 700;
    line-height: 1.3;
    margin: 0 0 var(--space-3);
}

.track-badges {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    margin-bottom: var(--space-3);
}

.track-badge {
    font-size: 0.75rem;
    font-weight: 600;
    padding: var(--space-1) var(--space-2);
    border-radius: var(--radius-sm);
    background: rgba(255, 255, 255, 0.15);
    border: 1px solid rgba(255, 255, 255, 0.25);
    backdrop-filter: blur(4px);
}

.track-badge.bestseller {
    background: var(--brand-secondary);
    color: #1f2328;
    border-color: transparent;
}

.track-instructors {
    display: flex;
    align-items: center;
}

.instructor-avatar-stack img {
    width: 28px;
    height: 28px;
    border-radius: var(--radius-full);
    border: 2px solid rgba(255, 255, 255, 0.7);
    margin-left: -8px;
}

.instructor-avatar-stack img:first-child {
    margin-left: 0;
}

.instructor-avatar-more {
    width: 28px;
    height: 28px;
    border-radius: var(--radius-full);
    border: 2px solid rgba(255, 255, 255, 0.7);
    margin-left: -8px;
    font-size: 0.7rem;
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: rgba(0, 0, 0, 0.4);
    color: var(--text-inverse);
}

/* Refined Hover Actions */
.track-actions-overlay {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    z-index: 3;
    padding: var(--space-4);
    display: flex;
    align-items: center;
    gap: var(--space-3);
    opacity: 0;
    transform: translateY(10px);
    transition: opacity var(--transition-base), transform var(--transition-base);
}

.degree-track-card:hover .track-actions-overlay {
    opacity: 1;
    transform: translateY(0);
}

.track-primary-btn {
    flex-grow: 1;
    padding: var(--space-3) var(--space-4);
    font-size: 0.9rem;
    font-weight: 600;
    border-radius: var(--radius-md);
    background: var(--text-inverse);
    color: var(--text-primary);
    text-decoration: none;
    text-align: center;
}

.track-primary-btn:hover {
    background: #fff;
    filter: brightness(0.95);
}

.track-icon-btn {
    flex-shrink: 0;
    width: 36px;
    height: 36px;
    border-radius: var(--radius-full);
    background: rgba(255, 255, 255, 0.15);
    border: 1px solid rgba(255, 255, 255, 0.25);
    display: grid;
    place-items: center;
    color: var(--text-inverse);
    font-size: 1rem;
    text-decoration: none;
    cursor: pointer;
}

.track-icon-btn:hover {
    background: rgba(255, 255, 255, 0.25);
}