/* 课程介绍列表 — 紧凑卡片 */
.courses-page {
    padding-bottom: 2rem;
}

.courses-grid {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 1rem;
}

@media (max-width: 991px) {
    .courses-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

@media (max-width: 575px) {
    .courses-grid {
        grid-template-columns: 1fr;
        gap: 0.85rem;
    }
}

.course-card {
    display: flex;
    flex-direction: column;
    height: 100%;
    min-height: 0;
    background: #fff;
    border: 1px solid rgba(226, 232, 240, 0.95);
    border-radius: 10px;
    overflow: hidden;
    box-shadow: 0 2px 12px rgba(15, 23, 42, 0.05);
    transition: box-shadow 0.22s ease, transform 0.22s ease, border-color 0.2s ease;
}

.course-card:hover {
    box-shadow: 0 10px 28px rgba(15, 23, 42, 0.09);
    transform: translateY(-2px);
    border-color: rgba(13, 110, 253, 0.18);
}

.course-card__media {
    display: block;
    height: 96px;
    overflow: hidden;
    background: #f1f5f9;
    flex-shrink: 0;
}

.course-card__media img {
    display: block;
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.35s ease;
}

.course-card:hover .course-card__media img {
    transform: scale(1.04);
}

.course-card__body {
    display: flex;
    flex-direction: column;
    flex: 1;
    min-height: 0;
    padding: 0.65rem 0.75rem 0.7rem;
    gap: 0.35rem;
}

.course-card__title {
    margin: 0;
    font-family: 'Source Sans Pro', sans-serif;
    font-size: 0.92rem;
    font-weight: 700;
    line-height: 1.35;
    min-height: 2.5em;
}

.course-card__title a {
    color: #1e293b;
    text-decoration: none;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.course-card__title a:hover {
    color: #0d6efd;
}

.course-card__desc {
    margin: 0;
    font-size: 0.75rem;
    line-height: 1.4;
    color: #64748b;
    display: -webkit-box;
    -webkit-line-clamp: 1;
    -webkit-box-orient: vertical;
    overflow: hidden;
    min-height: 1.4em;
}

.course-card__meta {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    gap: 0.5rem;
    margin-top: 0.1rem;
}

.course-card__price {
    font-size: 0.95rem;
    font-weight: 800;
    color: #dc3545;
    line-height: 1.2;
    white-space: nowrap;
}

.course-card__buyers {
    font-size: 0.72rem;
    color: #94a3b8;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.course-card__actions {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.45rem;
    margin-top: auto;
    padding-top: 0.45rem;
}

.course-card__btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 28px;
    min-width: 2.8em;
    padding: 0.28rem 0.55rem;
    font-family: 'Source Sans Pro', sans-serif;
    font-size: 0.82rem;
    font-weight: 600;
    letter-spacing: 0.04em;
    line-height: 1.2;
    text-align: center;
    text-decoration: none;
    border-radius: 6px;
    border: 1px solid transparent;
    transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease, transform 0.15s ease;
    white-space: nowrap;
}

.course-card__btn:hover {
    text-decoration: none;
    transform: translateY(-1px);
}

.course-card__btn--detail {
    color: #475569;
    background: #f8fafc;
    border-color: #e2e8f0;
}

.course-card__btn--detail:hover {
    color: #0d6efd;
    background: #eff6ff;
    border-color: #bfdbfe;
}

.course-card__btn--buy {
    color: #fff;
    background: linear-gradient(135deg, #dc3545, #c82333);
    border-color: #c82333;
    box-shadow: 0 2px 8px rgba(220, 53, 69, 0.22);
}

.course-card__btn--buy:hover {
    color: #fff;
    background: linear-gradient(135deg, #c82333, #bd2130);
    box-shadow: 0 4px 12px rgba(220, 53, 69, 0.28);
}

.courses-page__empty {
    grid-column: 1 / -1;
    padding: 3rem 1rem;
    text-align: center;
    color: #94a3b8;
}