:root {
    --navy: #102a43;
    --blue: #2563eb;
    --blue-dark: #1d4ed8;
    --sky: #eaf2ff;
    --ink: #243b53;
    --muted: #52667a;
    --line: #d9e2ec;
    --paper: #ffffff;
    --canvas: #f4f7fb;
}

*, *::before, *::after {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    scroll-padding-top: 5.5rem;
}

body,
body.bg-gray-50 {
    margin: 0;
    background: linear-gradient(180deg, #edf4ff 0, var(--canvas) 18rem);
    color: var(--ink);
    font-family: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    line-height: 1.65;
}

.course-header,
header.course-header.gradient-bg {
    padding: 4rem 1.5rem 3.5rem;
    background: linear-gradient(135deg, #0b2545, var(--blue-dark));
    color: #fff;
    text-align: center;
}

.course-header > .container {
    width: auto;
    max-width: none;
    padding: 0;
}

.course-header h1,
.course-header h1.text-4xl {
    margin: 0;
    color: #fff;
    font-size: clamp(2rem, 6vw, 3.75rem);
    font-weight: 750;
    line-height: 1.1;
    letter-spacing: -0.04em;
}

.course-header p,
.course-header p.mt-4 {
    margin: 1rem 0 0;
    color: #dce9f8;
    font-size: 1.05rem;
}

.course-nav {
    position: sticky;
    top: 0;
    z-index: 10;
    background: rgba(10, 37, 69, 0.96);
    box-shadow: 0 4px 16px rgba(15, 35, 60, 0.16);
}

.course-nav ul {
    display: flex;
    gap: 0.25rem;
    width: min(74rem, 100%);
    margin: 0 auto;
    padding: 0.65rem 1rem;
    overflow-x: auto;
    list-style: none;
}

.course-nav li {
    flex: 0 0 auto;
    margin: 0;
}

.course-nav a {
    display: block;
    padding: 0.55rem 0.8rem;
    border-radius: 0.55rem;
    color: #e6f0ff;
    font-size: 0.9rem;
    font-weight: 650;
    text-decoration: none;
}

.course-nav a:hover,
.course-nav a:focus-visible {
    background: rgba(255, 255, 255, 0.14);
    color: #fff;
}

main.course-main,
main.course-main.container {
    width: min(74rem, calc(100% - 2rem));
    max-width: none;
    margin: 0 auto;
    padding: 2rem 0 3rem;
}

.course-main > section,
.course-main > section.mb-12 {
    margin: 0 0 1.25rem;
    padding: clamp(1.25rem, 3vw, 2rem);
    overflow-x: auto;
    background: var(--paper);
    border: 1px solid rgba(217, 226, 236, 0.9);
    border-radius: 1rem;
    box-shadow: 0 10px 30px rgba(36, 59, 83, 0.07);
}

.course-main section h2,
.course-main section h2.text-2xl {
    margin: 0 0 0.8rem;
    padding: 0;
    border: 0;
    color: var(--navy);
    font-size: clamp(1.4rem, 3vw, 2rem);
    font-weight: 750;
    line-height: 1.25;
    letter-spacing: -0.025em;
}

.course-main h3,
.course-main h3.text-xl {
    margin: 1.35rem 0 0.65rem;
    color: var(--navy);
    font-size: 1.1rem;
    font-weight: 700;
}

.course-main p + p {
    margin-top: 0.65rem;
}

.course-main a,
.course-main a.text-blue-600 {
    color: var(--blue-dark);
    font-weight: 600;
    text-decoration: underline;
    text-decoration-thickness: 0.08em;
    text-underline-offset: 0.18em;
}

.course-main a:hover,
.course-main a.hover\:text-blue-800:hover {
    color: #123a9c;
}

.course-main .text-red-600 {
    color: #b42318;
}

.course-main ul {
    padding-left: 1.25rem;
    list-style: disc;
}

.course-main li + li {
    margin-top: 0.55rem;
}

.course-main .card,
.course-main section > div.bg-white {
    padding: 1.1rem;
    background: #f8fbff;
    border: 1px solid var(--line);
    border-left: 0.3rem solid var(--blue);
    border-radius: 0.7rem;
    box-shadow: none;
}

.course-main .card:hover {
    border-left-color: var(--blue-dark);
    box-shadow: 0 8px 20px rgba(36, 59, 83, 0.08);
}

.course-main .grid {
    grid-template-columns: repeat(auto-fit, minmax(min(100%, 18rem), 1fr));
}

#schedule > ul {
    display: grid;
    gap: 0.8rem;
    margin-top: 1.25rem;
    padding: 0;
    list-style: none;
}

#schedule > ul > li {
    margin: 0;
    padding: 1rem 1.1rem;
    background: #f8fbff;
    border: 1px solid var(--line);
    border-left: 0.3rem solid var(--blue);
    border-radius: 0.7rem;
}

#schedule > ul > li > p {
    margin-top: 0.65rem;
}

.course-main table {
    display: block;
    width: 100%;
    margin: 1.25rem 0;
    overflow-x: auto;
    border-collapse: collapse;
    border-radius: 0.75rem;
}

.course-main th,
.course-main td {
    min-width: 9rem;
    padding: 0.75rem;
    border: 1px solid var(--line);
    text-align: left;
    vertical-align: top;
}

.course-main th {
    background: var(--sky);
    color: var(--navy);
}

.course-main input {
    min-height: 2.75rem;
    border: 1px solid #b8c5d1;
    border-radius: 0.55rem;
    background: #fff;
}

.course-main button,
.course-main a.bg-blue-600 {
    min-height: 2.75rem;
    border: 0;
    border-radius: 0.55rem;
    background: var(--blue);
    color: #fff;
    cursor: pointer;
    font-weight: 700;
    text-decoration: none;
}

.course-main button:hover,
.course-main a.bg-blue-600:hover {
    background: var(--blue-dark);
    color: #fff;
}

.course-footer,
footer.course-footer.bg-gray-800 {
    padding: 2rem 1rem;
    background: var(--navy);
    color: #dce9f8;
    text-align: center;
}

.course-footer .container {
    width: auto;
    max-width: none;
}

.course-footer a {
    color: #fff;
}

a:focus-visible,
button:focus-visible,
input:focus-visible {
    outline: 3px solid #fbbf24;
    outline-offset: 3px;
}

@media (max-width: 640px) {
    .course-header,
    header.course-header.gradient-bg {
        padding: 3rem 1rem 2.5rem;
    }

    main.course-main,
    main.course-main.container {
        width: min(100% - 1rem, 74rem);
        padding-top: 1rem;
    }

    .course-main > section,
    .course-main > section.mb-12 {
        border-radius: 0.75rem;
    }
}