/* Portfolio of Oseni Sakariyau Oluwadamilare. Plain CSS, no external fonts or scripts; follows the system theme. */
:root {
  --bg: #f6f8fb;
  --surface: #ffffff;
  --text: #0f1b2d;
  --muted: #4a5a70;
  --border: #dde4ee;
  --accent: #0e6aa8;
  --accent-soft: #e3f0fa;
  --chip-bg: #eef2f7;
  --chip-text: #243449;
  --ok: #1f8a4c;
  --shadow: 0 1px 2px rgb(15 27 45 / 0.06), 0 4px 16px rgb(15 27 45 / 0.05);
  --mono: ui-monospace, SFMono-Regular, "Cascadia Code", Menlo, Consolas, monospace;
  --sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0a1220;
    --surface: #101b2e;
    --text: #e6edf6;
    --muted: #9fb0c5;
    --border: #1f2c43;
    --accent: #5cb8f2;
    --accent-soft: #10263c;
    --chip-bg: #16243a;
    --chip-text: #cfdbea;
    --ok: #4cc47f;
    --shadow: none;
  }
}

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

html { scroll-behavior: smooth; scroll-padding-top: 72px; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 17px/1.6 var(--sans);
  -webkit-font-smoothing: antialiased;
}

a { color: var(--accent); }
a:focus-visible, .button:focus-visible, .card:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 3px;
}

img { max-width: 100%; height: auto; display: block; }

.wrap { max-width: 1080px; margin: 0 auto; padding: 0 20px; }

.skip {
  position: absolute; left: -999px; top: 8px;
  background: var(--surface); color: var(--text); padding: 8px 12px; border-radius: 6px; z-index: 10;
}
.skip:focus { left: 8px; }

/* header */
.site-header {
  position: sticky; top: 0; z-index: 5;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}
.nav { display: flex; align-items: center; justify-content: space-between; gap: 16px; min-height: 60px; }
.brand { font-weight: 700; color: var(--text); text-decoration: none; letter-spacing: -0.01em; }
.nav nav { display: flex; gap: 20px; overflow-x: auto; }
.nav nav a { color: var(--muted); text-decoration: none; font-size: 15px; white-space: nowrap; }
.nav nav a:hover { color: var(--text); }

/* hero */
.hero { padding: 88px 0 72px; }
.eyebrow, .tag, .status, .num, .when {
  font-family: var(--mono);
  font-size: 14px;
  letter-spacing: 0.02em;
}
.eyebrow { color: var(--accent); margin: 0 0 12px; }
h1 {
  font-size: clamp(2.1rem, 5.5vw, 3.6rem);
  line-height: 1.08;
  letter-spacing: -0.025em;
  margin: 0 0 20px;
}
.lead { font-size: 1.2rem; color: var(--muted); max-width: 44rem; margin: 0 0 28px; }

.actions { display: flex; flex-wrap: wrap; gap: 12px; }
.button {
  display: inline-block; padding: 11px 20px; border-radius: 8px;
  border: 1px solid var(--border); background: var(--surface);
  color: var(--text); text-decoration: none; font-weight: 600; font-size: 15px;
}
.button:hover { border-color: var(--accent); }
.button.primary { background: var(--accent); border-color: var(--accent); color: var(--bg); }

/* sections */
.section { padding: 72px 0; }
.section.alt { background: var(--surface); border-block: 1px solid var(--border); }
.section-title {
  font-size: 1.6rem; letter-spacing: -0.015em; margin: 0 0 32px;
  display: flex; align-items: baseline; gap: 12px;
}
.num { color: var(--accent); font-size: 15px; }
.group { font-size: 1.05rem; color: var(--muted); font-weight: 600; margin: 40px 0 16px; }
.group:first-of-type { margin-top: 0; }

/* featured */
.feature {
  display: grid; grid-template-columns: minmax(0, 5fr) minmax(0, 6fr); gap: 40px; align-items: center;
}
.feature h3 { font-size: 2rem; margin: 6px 0 12px; letter-spacing: -0.02em; }
.status { display: inline-flex; align-items: center; gap: 8px; color: var(--muted); margin: 0; }
.dot { width: 8px; height: 8px; border-radius: 50%; background: var(--ok); }
.points { padding-left: 1.1rem; margin: 16px 0 20px; }
.points li { margin-bottom: 8px; }
.diagram {
  margin: 0; background: var(--surface); border: 1px solid var(--border); border-radius: 12px;
  padding: 12px; box-shadow: var(--shadow);
}
@media (prefers-color-scheme: dark) { .diagram { background: #000; } }
.diagram figcaption { font-size: 14px; color: var(--muted); margin-top: 8px; text-align: center; }
.links { display: flex; flex-wrap: wrap; gap: 8px 24px; margin: 0; }
.link { font-weight: 600; text-decoration: none; }
.link:hover { text-decoration: underline; }

/* cards */
.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 16px; }
.card {
  display: flex; flex-direction: column; gap: 6px;
  padding: 20px; border-radius: 12px; border: 1px solid var(--border);
  background: var(--bg); color: var(--text); text-decoration: none;
  transition: border-color 0.15s, transform 0.15s;
}
.section:not(.alt) .card { background: var(--surface); box-shadow: var(--shadow); }
.card:hover { border-color: var(--accent); transform: translateY(-2px); }
@media (prefers-reduced-motion: reduce) { .card:hover { transform: none; } }
.card h4 { margin: 0; font-size: 1.1rem; }
.card p { margin: 0; color: var(--muted); font-size: 15.5px; }
.card .tag { color: var(--accent); font-size: 13px; }
.card .chips { margin-top: auto; padding-top: 10px; }

.chips { list-style: none; padding: 0; margin: 0 0 20px; display: flex; flex-wrap: wrap; gap: 6px; }
.chips li {
  font-family: var(--mono); font-size: 12.5px; padding: 3px 9px; border-radius: 999px;
  background: var(--chip-bg); color: var(--chip-text);
}
.card .chips { margin-bottom: 0; }

/* journey + toolbox */
.two-col { display: grid; grid-template-columns: 1fr 1fr; gap: 56px; }
.timeline { list-style: none; margin: 0; padding: 0 0 0 20px; border-left: 2px solid var(--border); }
.timeline li { position: relative; margin: 0 0 22px; color: var(--muted); }
.timeline li::before {
  content: ""; position: absolute; left: -27px; top: 8px; width: 12px; height: 12px;
  border-radius: 50%; background: var(--surface); border: 2px solid var(--accent);
}
.timeline strong { color: var(--text); font-weight: 600; }
.when { display: block; color: var(--accent); font-size: 13px; }
.toolbox { margin: 0; }
.toolbox dt { font-weight: 600; margin-bottom: 8px; }
.toolbox dd { margin: 0 0 14px; }
.toolbox .chips { margin-bottom: 0; }

/* contact + footer */
.contact p { color: var(--muted); max-width: 40rem; margin: 0 0 24px; font-size: 1.1rem; }
.site-footer { border-top: 1px solid var(--border); padding: 28px 0 40px; color: var(--muted); font-size: 14px; }
.site-footer p { margin: 0; }

@media (max-width: 860px) {
  .feature, .two-col { grid-template-columns: 1fr; }
  .feature { gap: 28px; }
  .two-col { gap: 48px; }
}
@media (max-width: 600px) {
  .wrap { padding: 0 16px; }
  .nav { flex-direction: column; align-items: flex-start; gap: 4px; padding-block: 10px; }
  .nav nav { gap: 4px 12px; flex-wrap: wrap; width: 100%; padding-bottom: 2px; }
  .nav nav a { font-size: 14px; }
  .hero { padding: 56px 0 48px; }
  .section { padding: 56px 0; }
  html { scroll-padding-top: 100px; }
}