:root {
    --primary: #1f6f8b;
    --secondary: #2a9d8f;
    --accent: #f4a261;
    --background: #eef6f7;
    --surface: #ffffff;
    --ink: #17324d;
    --muted: #557080;
    --line: #b9d8de;
}

* {
    box-sizing: border-box;
}

html {
    background: var(--background);
}

body {
    min-height: 100vh;
    margin: 0;
    padding: 12px;
    color: var(--ink);
    background:
        radial-gradient(circle at top right, rgba(42, 157, 143, 0.18), transparent 32%),
        linear-gradient(145deg, #f7fbfc 0%, var(--background) 100%);
    font-family: Arial, Helvetica, sans-serif;
}

.home-card {
    width: min(1100px, 100%);
    margin: 0 auto;
    overflow: hidden;
    background: var(--surface);
    border: 1px solid rgba(31, 111, 139, 0.14);
    border-radius: 18px;
    box-shadow: 0 14px 34px rgba(23, 50, 77, 0.13);
}

.hero {
    padding: 42px clamp(20px, 6vw, 70px);
    color: #ffffff;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
}

.eyebrow {
    margin: 0 0 8px;
    font-size: 13px;
    font-weight: 700;
    letter-spacing: 0.06em;
    text-transform: uppercase;
}

h1,
h2,
p {
    margin-top: 0;
}

h1 {
    max-width: 760px;
    margin-bottom: 14px;
    font-size: clamp(30px, 5vw, 48px);
    line-height: 1.08;
}

h2 {
    margin-bottom: 12px;
    color: var(--primary);
    font-size: clamp(23px, 3vw, 30px);
}

.lead {
    max-width: 780px;
    margin-bottom: 0;
    color: #efffff;
    font-size: clamp(16px, 2.2vw, 20px);
    line-height: 1.55;
}

.introduction {
    display: grid;
    grid-template-columns: minmax(0, 1.35fr) minmax(260px, 0.85fr);
    gap: 30px;
    padding: 34px clamp(20px, 6vw, 70px);
}

.introduction p,
.section-heading p {
    color: var(--muted);
    font-size: 16px;
    line-height: 1.65;
}

.topic-list {
    display: grid;
    gap: 10px;
    align-content: start;
    margin: 0;
    padding: 0;
    list-style: none;
}

.topic-list li {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 14px;
    background: #f1f8f8;
    border: 1px solid var(--line);
    border-radius: 10px;
    font-size: 15px;
    line-height: 1.35;
}

.topic-list span {
    display: grid;
    flex: 0 0 34px;
    height: 34px;
    place-items: center;
    color: #ffffff;
    background: var(--secondary);
    border-radius: 50%;
    font-size: 12px;
    font-weight: 700;
}

.video-section {
    padding: 34px clamp(20px, 6vw, 70px);
    background: #f6fafb;
    border-top: 1px solid var(--line);
}

.section-heading {
    max-width: 800px;
    margin-bottom: 20px;
}

.section-heading .eyebrow {
    color: var(--secondary);
}

.video-frame {
    position: relative;
    width: min(900px, 100%);
    margin: 0 auto;
    overflow: hidden;
    background: #102b3a;
    border: 5px solid #ffffff;
    border-radius: 14px;
    box-shadow: 0 10px 28px rgba(23, 50, 77, 0.18);
    aspect-ratio: 16 / 9;
}

.video-frame iframe {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    border: 0;
}

.video-link {
    margin: 14px 0 0;
    color: var(--muted);
    font-size: 14px;
    text-align: center;
}

.video-link a {
    color: var(--primary);
    font-weight: 700;
}

.start-message {
    margin: 0;
    padding: 18px 24px;
    color: #ffffff;
    background: var(--ink);
    text-align: center;
    font-size: 15px;
    font-weight: 700;
}

@media (max-width: 720px) {
    body {
        padding: 6px;
    }

    .home-card {
        border-radius: 12px;
    }

    .hero {
        padding-top: 30px;
        padding-bottom: 30px;
    }

    .introduction {
        grid-template-columns: 1fr;
        gap: 20px;
    }
}