@import url("https://fonts.googleapis.com/css2?family=Space+Mono:wght@400;700&family=DM+Sans:wght@400;500;600;700&display=swap");

:root {
    --bg: #0f1419;
    --bg-secondary: #1a1f26;
    --ink: #f0f2f5;
    --muted: #8b92a0;
    --accent: #00d9ff;
    --accent-hover: #33e5ff;
    --rule: #252c38;
    --success-bg: rgba(34, 197, 94, 0.15);
    --success-ink: #86efac;
    --warn-bg: rgba(239, 68, 68, 0.15);
    --warn-ink: #fca5a5;
}

* {
    box-sizing: border-box;
}

html,
body {
    margin: 0;
    padding: 0;
    background: var(--bg);
    color: var(--ink);
    font-family:
        "DM Sans",
        -apple-system,
        BlinkMacSystemFont,
        sans-serif;
    line-height: 1.6;
    font-size: 16px;
}

main {
    max-width: 960px;
    margin: 0 auto;
    padding: 4rem 2rem 5rem;
}

h1,
h2,
h3 {
    font-family: "Space Mono", monospace;
    font-weight: 700;
    line-height: 1.25;
    margin: 0 0 0.5em;
    letter-spacing: 0.02em;
}

h1 {
    font-size: 3.2rem;
    letter-spacing: -0.02em;
    margin-bottom: 0.3em;
}

h2 {
    font-size: 1.5rem;
    color: var(--muted);
    font-weight: 400;
    letter-spacing: 0.01em;
    margin-bottom: 1.5rem;
}

h3 {
    margin-top: 3.5rem;
    margin-bottom: 1.5rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--muted);
}

p {
    font-size: 1.05rem;
    margin: 1rem 0;
}

.hero {
    text-align: center;
    padding: 2rem 0 4rem;
    border-bottom: 1px solid var(--rule);
    margin-bottom: 3rem;
}

.byline {
    color: var(--muted);
    margin: 1rem 0 0;
    font-size: 0.95rem;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

.intro {
    display: flex;
    gap: 3.5rem;
    align-items: flex-start;
    margin: 2rem 0 4rem;
}

.cover {
    width: 480px;
    max-width: 35%;
    height: auto;
    flex-shrink: 0;
    box-shadow: 0 20px 60px rgba(0, 217, 255, 0.1);
    border-radius: 0;
    border: 1px solid var(--rule);
}

.intro-text {
    flex: 1;
    display: flex;
    flex-direction: column;
}

.lede {
    font-size: 1.5rem;
    margin: 0;
    line-height: 1.7;
    color: var(--ink);
    font-weight: 500;
}

.buy-cta {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    margin-top: 2rem;
    align-items: center;
    justify-content: center;
}

.price-display {
    margin: 0 auto 2rem;
    font-size: 3.5rem;
    font-weight: 700;
    font-family:
        "DM Sans",
        -apple-system,
        BlinkMacSystemFont,
        sans-serif;
    color: var(--accent);
    line-height: 1;
    letter-spacing: -0.02em;
}

.buy-button {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 100%;
    background: var(--accent);
    color: var(--bg);
    border: none;
    border-radius: 0;
    font-family: "Space Mono", monospace;
    font-size: 1.5rem;
    font-weight: 700;
    padding: 1.5rem 3.5rem;
    cursor: pointer;
    text-decoration: none;
    transition: all 0.2s ease;
    letter-spacing: 0.03em;
    text-transform: uppercase;
}

.buy-button:hover:not(:disabled) {
    background: var(--accent-hover);
    transform: translateY(-2px);
    box-shadow: 0 12px 24px rgba(0, 217, 255, 0.2);
}

.buy-button:disabled {
    opacity: 0.5;
    cursor: wait;
}

.buy-subtext {
    margin: 0;
    font-size: 1rem;
    color: var(--muted);
    font-weight: 400;
    text-transform: uppercase;
    letter-spacing: 0.03em;
}

.buy-note {
    font-size: 0.9rem;
    color: var(--muted);
    margin: 0.5rem 0 0;
    font-weight: 400;
    text-align: center;
}

.topic-list {
    padding-left: 0;
    list-style: none;
}

.topic-list > li {
    margin-bottom: 1.5rem;
    padding-left: 0;
}

.topic-list strong {
    font-size: 1.1rem;
    display: block;
    margin-bottom: 0.5rem;
    color: var(--accent);
    text-transform: uppercase;
    letter-spacing: 0.06em;
    font-weight: 700;
}

.topic-list ul {
    padding-left: 1.5rem;
    list-style: none;
    margin: 0;
}

.topic-list ul li {
    margin-bottom: 0.5rem;
    position: relative;
    padding-left: 1.25rem;
    font-size: 1.5rem;
}

.topic-list ul li:before {
    content: "→";
    position: absolute;
    left: -0.25rem;
    color: var(--accent);
}

.topic-list ul ul {
    padding-left: 1.25rem;
    margin-top: 0.5rem;
}

.topic-list ul ul li:before {
    content: "–";
}

.author {
    margin-top: 3.5rem;
}

.author p {
    font-size: 1.5rem;
    line-height: 1.75;
}

.links {
    margin-top: 1.5rem;
    display: flex;
    gap: 1.5rem;
}

.links a {
    color: var(--accent);
    text-decoration: none;
    font-weight: 600;
    font-size: 0.95rem;
    text-transform: uppercase;
    letter-spacing: 0.03em;
    transition: color 0.2s ease;
}

.links a:hover {
    color: var(--accent-hover);
}

.testimonials {
    margin-top: 4rem;
}

.testimonials blockquote {
    margin: 2rem 0;
    padding: 2rem 2rem;
    border-left: none;
    border-top: 1px solid var(--rule);
    border-bottom: 1px solid var(--rule);
    background: var(--bg-secondary);
}

.testimonials p {
    margin: 0;
    font-size: 1.5rem;
    line-height: 1.75;
    font-style: italic;
}

.testimonials cite {
    display: block;
    margin-top: 1.25rem;
    font-style: normal;
    color: var(--muted);
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.03em;
}

.testimonials a {
    color: var(--accent);
    text-decoration: none;
}

.testimonials a:hover {
    color: var(--accent-hover);
}

.banner {
    padding: 1.75rem 2rem;
    border-radius: 0;
    margin-bottom: 2.5rem;
    margin-top: -2rem;
    margin-left: -2rem;
    margin-right: -2rem;
    padding-left: 2rem;
    font-family: "DM Sans", sans-serif;
    font-size: 1.1rem;
    border-left: 4px solid;
    line-height: 1.6;
}

.banner.success {
    background: var(--success-bg);
    color: var(--success-ink);
    border-left-color: var(--success-ink);
}

.banner.warn {
    background: var(--warn-bg);
    color: var(--warn-ink);
    border-left-color: var(--warn-ink);
}

footer {
    margin-top: 5rem;
    padding-top: 2rem;
    border-top: 1px solid var(--rule);
    text-align: center;
    color: var(--muted);
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 0.03em;
}

@media (max-width: 768px) {
    main {
        padding: 2.5rem 1.5rem 3.5rem;
    }
    h1 {
        font-size: 2.4rem;
    }
    h2 {
        font-size: 1.25rem;
    }
    .intro {
        flex-direction: column;
        gap: 2rem;
    }
    .cover {
        width: 100%;
        max-width: 300px;
        margin: 0 auto;
    }
    .intro-text {
        text-align: center;
        align-items: center;
    }
    .hero {
        padding: 1.5rem 0 2.5rem;
        margin-bottom: 2rem;
    }
}