:root {
    --bg: #0b0f14;
    --panel: #101824;
    --text: #e7eef8;
    --muted: #a9b7c9;
    --accent: #7aa2ff;
    --border: rgba(255, 255, 255, 0.08);
}

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial;
    background: var(--bg);
    color: var(--text);
}

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

a:hover {
    text-decoration: underline;
}

.topbar {
    position: sticky;
    top: 0;
    z-index: 50;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    padding: 14px 18px;
    background: rgba(11, 15, 20, 0.85);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border);
}

.brand {
    font-weight: 700;
    letter-spacing: 0.3px;
}

.nav {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.nav-link {
    padding: 8px 10px;
    border-radius: 10px;
    color: var(--muted);
    border: 1px solid transparent;
}

.nav-link.is-active {
    color: var(--text);
    border-color: var(--border);
    background: rgba(255, 255, 255, 0.04);
}

.section {
    padding: 64px 18px;
}

.hero {
    max-width: 1040px;
    margin: 0 auto;
    padding-top: 56px;
}

.hero-content h1 {
    font-size: clamp(28px, 3vw, 44px);
    margin: 0 0 12px;
}

.hero-content p {
    color: var(--muted);
    max-width: 72ch;
    line-height: 1.55;
}

.hero-cta {
    display: flex;
    gap: 10px;
    margin-top: 18px;
}

.button {
    display: inline-block;
    padding: 10px 14px;
    border-radius: 12px;
    border: 1px solid var(--border);
    background: rgba(255, 255, 255, 0.05);
    color: var(--text);
}

.button.secondary {
    background: transparent;
    color: var(--muted);
}

.scrolly {
    padding: 0 18px 64px;
}

.scrolly-grid {
    max-width: 1040px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1.1fr 0.9fr;
    gap: 28px;
    align-items: start;
}

.steps {
    display: flex;
    flex-direction: column;
    gap: 36px;
}

.step {
    padding: 18px 16px;
    border-radius: 16px;
    border: 1px solid var(--border);
    background: rgba(255, 255, 255, 0.03);
    min-height: 10vh;
    /* ensures each step has scroll room */
}

.step h2 {
    margin: 0 0 10px;
}

.step p,
.step li {
    color: var(--muted);
    line-height: 1.6;
}

.step ul {
    margin: 10px 0 0 18px;
}

.viz {
    position: sticky;
    top: 120px;
    /* below navbar */
    height: calc(100vh - 300px);
}

.viz-inner {

    border-radius: 16px;
    border: 1px solid var(--border);
    background: linear-gradient(180deg, rgba(255, 255, 255, 0.04), rgba(255, 255, 255, 0.02));
    padding: 14px;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.viz-header h3 {
    margin: 0;
}

.viz-header p {
    margin: 6px 0 0;
    color: var(--muted);
}

#viz-svg {
    width: 100%;
    height: 100%;
    border-radius: 12px;
    background: rgba(0, 0, 0, 0.18);
    border: 1px solid var(--border);
}

.footer {
    border-top: 1px solid var(--border);
    padding: 18px;
    color: var(--muted);
    text-align: center;
}

/* Mobile layout */
@media (max-width: 900px) {
    .scrolly-grid {
        grid-template-columns: 1fr;
    }

    .viz {
        position: relative;
        top: auto;
        height: 380px;
    }

    .step {
        min-height: auto;
    }
}