/* =========================================================
   COURSE DETAILS - RICH LEARNING APP UI
   Web + Mobile | Dark + Light | SEO/AdSense Friendly
========================================================= */

.course-detail-page {
    min-height: 100vh;
    background:
            radial-gradient(circle at 10% 0%, rgba(56,189,248,.16), transparent 30%),
            radial-gradient(circle at 90% 18%, rgba(14,165,233,.10), transparent 34%),
            var(--bg);
}

body.light .course-detail-page {
    background:
            radial-gradient(circle at 10% 0%, rgba(2,132,199,.12), transparent 32%),
            radial-gradient(circle at 95% 16%, rgba(186,230,253,.55), transparent 34%),
            #f8fafc;
}

.course-detail-section {
    padding: 28px 10px 42px;
}

.course-detail-section .container {
    max-width: 1220px;
}

/* Breadcrumb */
.course-breadcrumb {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 18px;
    font-size: .86rem;
    font-weight: 800;
}

.course-breadcrumb a {
    color: var(--primary) !important;
    text-decoration: none;
}

.course-breadcrumb span {
    color: var(--text);
    opacity: .72;
}

/* Hero */
.course-hero-card {
    position: relative;
    overflow: hidden;
    padding: 38px;
    border-radius: 34px;
    background:
            linear-gradient(135deg, rgba(15,23,42,.95), rgba(30,41,59,.92)),
            radial-gradient(circle at top right, rgba(56,189,248,.24), transparent 38%);
    border: 1px solid rgba(125,211,252,.18);
    box-shadow: 0 24px 70px rgba(0,0,0,.28);
}

body.light .course-hero-card {
    background:
            radial-gradient(circle at top right, rgba(2,132,199,.12), transparent 38%),
            #ffffff;
    border-color: rgba(2,132,199,.16);
    box-shadow: 0 20px 50px rgba(15,23,42,.10);
}

.course-hero-card::after {
    content: "📘";
    position: absolute;
    right: 34px;
    top: 30px;
    font-size: 5rem;
    opacity: .07;
}

.course-badge {
    display: inline-flex;
    margin-bottom: 14px;
    padding: 8px 14px;
    border-radius: 999px;
    color: var(--primary);
    background: rgba(56,189,248,.13);
    border: 1px solid rgba(56,189,248,.22);
    font-size: .8rem;
    font-weight: 900;
}

.course-title {
    max-width: 820px;
    font-size: clamp(2.4rem, 5vw, 4.1rem);
    line-height: 1.05;
    font-weight: 950;
    letter-spacing: -.8px;
    margin: 0 0 16px;
    color: var(--text);
}

.course-description {
    max-width: 900px;
    margin: 0 0 12px;
    font-size: 1.02rem;
    line-height: 1.75;
    color: var(--text);
    opacity: .86;
}

.course-description strong {
    color: var(--text);
}

.course-stats {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 22px;
}

.course-stats span {
    display: inline-flex;
    align-items: center;
    padding: 8px 13px;
    border-radius: 999px;
    background: rgba(56,189,248,.13);
    border: 1px solid rgba(56,189,248,.18);
    color: var(--primary);
    font-size: .78rem;
    font-weight: 900;
}

/* Benefit Cards */
.course-info-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 18px;
    margin: 28px 0 34px;
}

.course-info-card {
    padding: 24px;
    border-radius: 26px;
    background:
            radial-gradient(circle at top right, rgba(56,189,248,.13), transparent 38%),
            var(--card);
    border: 1px solid var(--navbar-border);
    box-shadow: 0 14px 34px rgba(15,23,42,.10);
}

body.light .course-info-card {
    background: #ffffff;
    border-color: rgba(2,132,199,.14);
}

.course-info-card h2 {
    font-size: 1.25rem;
    font-weight: 950;
    margin-bottom: 10px;
    color: var(--text);
}

.course-info-card p {
    margin: 0;
    font-size: .95rem;
    line-height: 1.65;
    opacity: .78;
    color: var(--text);
}

/* Section Heading */
.section-heading {
    text-align: left;
    margin-bottom: 18px;
}

.section-heading h2,
.course-faq-section h2 {
    font-size: clamp(1.7rem, 4vw, 2.4rem);
    font-weight: 950;
    letter-spacing: -.4px;
    margin-bottom: 8px;
    color: var(--text);
}

.section-heading p {
    max-width: 720px;
    margin: 0;
    opacity: .72;
    line-height: 1.65;
}

/* Topic Cards */
.course-topic-section {
    margin-top: 8px;
}

.course-topic-list {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 14px;
}

.course-topic-item {
    display: flex;
    align-items: center;
    gap: 14px;
    min-height: 96px;
    padding: 18px;
    border-radius: 24px;
    text-decoration: none;
    background:
            radial-gradient(circle at top right, rgba(56,189,248,.10), transparent 34%),
            rgba(15,23,42,.86);
    border: 1px solid rgba(125,211,252,.14);
    color: var(--text);
    transition: .22s ease;
}

body.light .course-topic-item {
    background: #ffffff;
    border-color: rgba(2,132,199,.14);
    box-shadow: 0 8px 24px rgba(15,23,42,.055);
}

.course-topic-item:hover {
    transform: translateY(-3px);
    border-color: var(--primary);
}

.topic-number {
    width: 44px;
    height: 44px;
    min-width: 44px;
    border-radius: 16px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: rgba(56,189,248,.14);
    color: var(--primary);
    font-size: .9rem;
    font-weight: 950;
}

.topic-content {
    min-width: 0;
    flex: 1;
}

.topic-title {
    display: block;
    color: var(--text);
    font-size: 1rem;
    line-height: 1.3;
    font-weight: 950;
    margin-bottom: 5px;
}

.topic-subtitle {
    display: block;
    color: var(--text);
    font-size: .78rem;
    line-height: 1.45;
    opacity: .72;
}

.topic-arrow {
    color: var(--primary);
    font-size: 1.15rem;
    font-weight: 950;
}

/* FAQ */
.course-faq-section {
    margin-top: 38px;
}

.faq-card {
    padding: 20px 22px;
    border-radius: 22px;
    margin-bottom: 12px;
    background: var(--card);
    border: 1px solid var(--navbar-border);
}

body.light .faq-card {
    background: #ffffff;
    border-color: rgba(2,132,199,.14);
}

.faq-card h3 {
    font-size: 1rem;
    font-weight: 950;
    margin-bottom: 8px;
    color: var(--text);
}

.faq-card p {
    margin: 0;
    font-size: .92rem;
    line-height: 1.65;
    opacity: .78;
    color: var(--text);
}

/* Ad section */
.course-ad-section {
    padding: 0 10px 34px;
}

.course-ad-section .container {
    max-width: 1220px;
}

.ad-placeholder-content {
    padding: 18px 16px;
    border-radius: 22px;
    text-align: center;
    background: rgba(56,189,248,.06);
    border: 1px dashed rgba(56,189,248,.25);
}

.ad-placeholder-content h4 {
    font-size: .95rem;
    font-weight: 950;
    margin-bottom: 6px;
}

.ad-placeholder-content p {
    margin: 0;
    font-size: .84rem;
    line-height: 1.55;
    opacity: .76;
}

/* Reading progress */
#readingProgress {
    position: fixed;
    top: 0;
    left: 0;
    height: 3px;
    width: 0;
    background: linear-gradient(90deg, #38bdf8, #0ea5e9);
    z-index: 10000;
}

/* Tablet */
@media (max-width: 991px) {
    .course-info-grid {
        grid-template-columns: 1fr;
    }

    .course-topic-list {
        grid-template-columns: 1fr;
    }
}

/* Mobile */
@media (max-width: 768px) {
    .course-detail-section {
        padding: 12px 8px 28px;
    }

    .course-detail-section .container {
        padding-left: 10px;
        padding-right: 10px;
    }

    .course-breadcrumb {
        font-size: .74rem;
        margin-bottom: 12px;
    }

    .course-hero-card {
        padding: 22px 18px;
        border-radius: 24px;
    }

    .course-hero-card::after {
        font-size: 3.2rem;
        right: 18px;
        top: 18px;
    }

    .course-badge {
        font-size: .72rem;
        padding: 7px 11px;
    }

    .course-title {
        font-size: 2.15rem;
        margin-bottom: 12px;
    }

    .course-description {
        font-size: .92rem;
        line-height: 1.65;
    }

    .course-stats {
        gap: 7px;
        margin-top: 16px;
    }

    .course-stats span {
        font-size: .68rem;
        padding: 6px 9px;
    }

    .course-info-grid {
        gap: 12px;
        margin: 18px 0 26px;
    }

    .course-info-card {
        padding: 18px;
        border-radius: 20px;
    }

    .course-info-card h2 {
        font-size: 1.12rem;
    }

    .course-info-card p {
        font-size: .86rem;
    }

    .section-heading h2,
    .course-faq-section h2 {
        font-size: 1.55rem;
    }

    .section-heading p {
        font-size: .88rem;
    }

    .course-topic-list {
        gap: 10px;
    }

    .course-topic-item {
        min-height: 82px;
        padding: 14px;
        border-radius: 18px;
    }

    .topic-number {
        width: 36px;
        height: 36px;
        min-width: 36px;
        border-radius: 13px;
        font-size: .78rem;
    }

    .topic-title {
        font-size: .95rem;
    }

    .topic-subtitle {
        font-size: .72rem;
    }

    .faq-card {
        padding: 16px;
        border-radius: 18px;
    }
}