body {
    font-family: 'Inter', sans-serif;
    background-color: #0d1117;
    color: #e6edf3;
    padding-top: 64px;
    --course-accent: #58a6ff;
    --course-accent-rgb: 88, 166, 255;
}

.navbar-dark-custom {
    background-color: #161b22;
    border-bottom: 1px solid #30363d;
}

.navbar-brand-custom {
    color: #e6edf3 !important;
    font-weight: 700;
    letter-spacing: 0.05em;
}

.nav-link-custom {
    color: #8b949e !important;
    font-weight: 600;
    transition: color 0.2s;
}

.nav-link-custom:hover,
.nav-link-custom.active {
    color: #e6edf3 !important;
}

.page-hero {
    background: radial-gradient(900px circle at 50% -20%, rgba(var(--course-accent-rgb), 0.12), transparent 60%), #0d1117;
    padding: 60px 0 50px;
    border-bottom: 1px solid #30363d;
}

.course-card,
.contact-card {
    background-color: #161b22;
    border: 1px solid #30363d;
    border-radius: 12px;
    transition: border-color 0.2s, transform 0.2s, box-shadow 0.2s;
}

.course-card {
    padding: 1.75rem;
    height: 100%;
    display: flex;
    flex-direction: column;
}

.course-card:hover,
.contact-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.4);
}

.course-card:hover {
    border-color: #58a6ff;
}

.course-icon,
.contact-icon,
.course-icon-lg {
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.course-icon {
    width: 48px;
    height: 48px;
    border-radius: 10px;
    font-size: 1.4rem;
    margin-bottom: 1rem;
}

.course-title {
    color: #e6edf3;
    font-weight: 700;
    font-size: 1.05rem;
    margin-bottom: 0.6rem;
    line-height: 1.4;
}

.course-description {
    color: #8b949e;
    font-size: 0.9rem;
    line-height: 1.6;
    flex-grow: 1;
    margin-bottom: 1.25rem;
}

.course-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
    margin-top: auto;
}

.badge-custom {
    font-size: 0.78rem;
    font-weight: 600;
    padding: 0.3em 0.7em;
    border-radius: 6px;
    border: 1px solid;
}

.contact-card {
    padding: 1.5rem 1.75rem;
    display: flex;
    align-items: center;
    gap: 1.25rem;
    text-decoration: none;
}

.contact-card:hover {
    text-decoration: none;
}

.contact-icon {
    width: 52px;
    height: 52px;
    border-radius: 12px;
    font-size: 1.5rem;
}

.contact-label {
    font-weight: 700;
    font-size: 1rem;
    color: #e6edf3;
    margin-bottom: 0.15rem;
}

.contact-handle {
    font-size: 0.85rem;
    color: #8b949e;
}

.contact-arrow {
    margin-left: auto;
    color: #30363d;
    font-size: 0.9rem;
    transition: color 0.2s, transform 0.2s;
}

.contact-card:hover .contact-arrow {
    color: #8b949e;
    transform: translateX(3px);
}

.course-hero {
    background: radial-gradient(800px circle at 80% 50%, rgba(var(--course-accent-rgb), 0.08), transparent 60%),
                radial-gradient(600px circle at 20% 50%, rgba(var(--course-accent-rgb), 0.05), transparent 60%), #0d1117;
    padding: 60px 0;
    border-bottom: 1px solid #30363d;
}

.course-icon-lg {
    width: 64px;
    height: 64px;
    border-radius: 14px;
    background-color: rgba(var(--course-accent-rgb), 0.12);
    font-size: 1.8rem;
}

.badge-level {
    font-size: 0.78rem;
    font-weight: 600;
    padding: 0.3em 0.8em;
    border-radius: 20px;
    border: 1px solid rgba(var(--course-accent-rgb), 0.4);
    background-color: rgba(var(--course-accent-rgb), 0.1);
    color: var(--course-accent);
}

.meta-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: #8b949e;
    font-size: 0.9rem;
}

.meta-item i {
    color: var(--course-accent);
    width: 16px;
}

.accordion-item {
    background-color: #161b22;
    border: 1px solid #30363d;
    border-radius: 10px !important;
    overflow: hidden;
    margin-bottom: 0.5rem;
}

.accordion-button {
    background-color: #161b22;
    color: #e6edf3;
    font-weight: 600;
    font-size: 0.95rem;
    padding: 1rem 1.25rem;
    border: none;
    box-shadow: none !important;
}

.accordion-button:not(.collapsed) {
    background-color: #1c2128;
    color: var(--course-accent);
    box-shadow: none !important;
}

.accordion-button::after {
    filter: invert(1) brightness(0.6);
}

.module-badge {
    flex-shrink: 0;
    margin-right: 1rem;
    padding: 0.25rem 0.65rem;
    border: 1px solid rgba(var(--course-accent-rgb), 0.35);
    border-radius: 999px;
    background-color: rgba(var(--course-accent-rgb), 0.1);
    color: var(--course-accent);
    font-size: 0.75rem;
    font-weight: 700;
    line-height: 1.2;
    white-space: nowrap;
}

.accordion-body {
    background-color: #161b22;
    border-top: 1px solid #30363d;
    padding: 1rem 1.25rem;
}

.topic-list {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
}

.topic-list li {
    display: flex;
    align-items: flex-start;
    gap: 0.6rem;
    color: #8b949e;
    font-size: 0.9rem;
    line-height: 1.5;
}

.topic-list li i {
    color: var(--course-accent);
    margin-top: 3px;
    flex-shrink: 0;
    font-size: 0.7rem;
}

.sidebar-card {
    background-color: #161b22;
    border: 1px solid #30363d;
    border-radius: 12px;
    padding: 1.5rem;
    position: sticky;
    top: 80px;
}

.sidebar-card h5 {
    color: #e6edf3;
    font-weight: 700;
    margin-bottom: 1rem;
}

.sidebar-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;
    padding: 0.6rem 0;
    border-bottom: 1px solid #21262d;
    font-size: 0.88rem;
}

.sidebar-item:last-child {
    border-bottom: none;
}

.sidebar-item .label {
    color: #8b949e;
}

.sidebar-item .value {
    color: #e6edf3;
    font-weight: 600;
    text-align: right;
}

.highlight-box {
    background-color: rgba(var(--course-accent-rgb), 0.05);
    border: 1px solid rgba(var(--course-accent-rgb), 0.3);
    border-radius: 12px;
    padding: 1.25rem;
}

.highlight-box h3 {
    color: var(--course-accent);
    font-size: 1rem;
    font-weight: 700;
    margin-bottom: 0.75rem;
}

.highlight-box p,
.highlight-box li {
    color: #8b949e;
    font-size: 0.9rem;
    line-height: 1.6;
}

.coming-soon {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.25rem;
    background-color: #21262d;
    color: #8b949e;
    border: 1px solid #30363d;
    border-radius: 8px;
    font-weight: 600;
}

.cta-button {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    background-color: var(--course-accent);
    color: #0d1117;
    border-radius: 8px;
    font-weight: 700;
    text-decoration: none;
    transition: transform 0.2s, box-shadow 0.2s;
}

.cta-button:hover {
    color: #0d1117;
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(var(--course-accent-rgb), 0.3);
}

footer {
    background-color: #161b22;
    border-top: 1px solid #30363d;
}