/* biopb.org — light, clean scientific landing page. Plain CSS, no build step. */

:root {
  --accent: #2563d6;          /* single accent — retune here */
  --accent-dark: #1b49a0;
  --ink: #14181f;             /* near-black text */
  --ink-soft: #4b5563;        /* secondary text */
  --line: #e6e8ec;            /* hairlines */
  --bg: #ffffff;
  --bg-soft: #f6f8fa;         /* alternating panels */
  --term-bg: #0f1722;         /* the one dark element */
  --term-ink: #e7edf5;
  --radius: 14px;
  --maxw: 1080px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font);
  color: var(--ink);
  background: var(--bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

.container { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }

/* ===== Nav ===== */
.nav {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: saturate(180%) blur(8px);
  border-bottom: 1px solid var(--line);
}
.nav__inner { display: flex; align-items: center; justify-content: space-between; height: 60px; }
.brand { display: inline-flex; align-items: center; gap: 9px; color: var(--ink); font-weight: 700; }
.brand:hover { text-decoration: none; }
.brand__logo { display: block; border-radius: 6px; }
.brand__name { font-size: 1.15rem; letter-spacing: -0.01em; }
.nav__links { display: flex; align-items: center; gap: 26px; }
.nav__links a { color: var(--ink-soft); font-weight: 500; font-size: 0.95rem; }
.nav__links a:hover { color: var(--ink); text-decoration: none; }
.nav__gh {
  color: var(--bg) !important; background: var(--ink);
  padding: 7px 15px; border-radius: 999px; font-weight: 600;
}
.nav__gh:hover { background: #000; }
.nav__toggle {
  display: none; background: none; border: 0; font-size: 1.6rem;
  line-height: 1; color: var(--ink); cursor: pointer; padding: 4px 8px;
}

/* ===== Hero ===== */
.hero { padding: 84px 0 72px; border-bottom: 1px solid var(--line); }
.hero__inner { max-width: 760px; }
.hero__title {
  font-size: clamp(2.3rem, 6vw, 3.6rem); line-height: 1.08;
  letter-spacing: -0.025em; margin: 0 0 18px; font-weight: 800;
}
.hero__sub { font-size: 1.18rem; color: var(--ink-soft); margin: 0 0 30px; max-width: 620px; }

/* terminal install window */
.term {
  background: var(--term-bg); border-radius: var(--radius);
  box-shadow: 0 18px 40px -20px rgba(15, 23, 34, 0.45);
  overflow: hidden; max-width: 640px;
}
.term__bar {
  display: flex; align-items: center; gap: 7px;
  padding: 10px 14px; background: rgba(255, 255, 255, 0.04);
  border-bottom: 1px solid rgba(255, 255, 255, 0.07);
}
.term__dot { width: 11px; height: 11px; border-radius: 50%; background: #3a4654; }
.term__dot:nth-child(1) { background: #ff5f57; }
.term__dot:nth-child(2) { background: #febc2e; }
.term__dot:nth-child(3) { background: #28c840; }
.term__title { margin-left: 8px; color: #8a97a6; font-size: 0.8rem; font-family: var(--mono); }
.term__body {
  display: flex; align-items: center; gap: 12px;
  padding: 18px 16px; font-family: var(--mono); font-size: 0.95rem;
}
.term__body code { color: var(--term-ink); overflow-x: auto; white-space: nowrap; flex: 1; }
.term__prompt { color: #28c840; user-select: none; margin-right: 8px; }
.term__copy {
  flex: none; cursor: pointer; font: inherit; font-size: 0.82rem;
  color: var(--term-ink); background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.14); border-radius: 8px;
  padding: 6px 12px; transition: background 0.15s, color 0.15s;
}
.term__copy:hover { background: rgba(255, 255, 255, 0.16); }
.term__copy.is-copied { background: #28c840; color: #06220f; border-color: #28c840; }

.hero__note { font-size: 0.92rem; color: var(--ink-soft); margin: 22px 0 0; }
/* ===== How it works ===== */
.howto { padding: 64px 0; background: var(--bg-soft); border-top: 1px solid var(--line); }
.howto .section__title { margin-bottom: 36px; }
.howto__fig { margin: 0 auto; max-width: 660px; }
.howto__fig img {
  width: 100%; height: auto; display: block;
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  padding: 20px;
}

/* ===== Components ===== */
.components { padding: 80px 0 40px; }
.section__title {
  font-size: clamp(1.6rem, 3.5vw, 2.1rem); font-weight: 800; letter-spacing: -0.02em;
  text-align: center; margin: 0 0 56px;
}
.row {
  display: grid; grid-template-columns: 1fr 1fr; gap: 48px;
  align-items: center; margin-bottom: 72px;
}
.row--reverse .shot { order: 2; }
.row__text .kicker {
  display: inline-block; font-size: 0.78rem; font-weight: 700; letter-spacing: 0.06em;
  text-transform: uppercase; color: var(--accent); margin-bottom: 10px;
}
.row__text h3 { font-size: 1.5rem; font-weight: 750; letter-spacing: -0.015em; margin: 0 0 12px; }
.row__text p { color: var(--ink-soft); margin: 0; font-size: 1.04rem; }

/* screenshot placeholder — swap the .shot__ph div for an <img> when ready */
.shot { margin: 0; }
.shot__ph {
  aspect-ratio: 16 / 9; width: 100%;
  background: var(--bg-soft); border: 1px solid var(--line); border-radius: var(--radius);
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  gap: 10px; color: var(--ink-soft); text-align: center; padding: 20px;
  background-image:
    linear-gradient(45deg, rgba(0,0,0,0.018) 25%, transparent 25%, transparent 75%, rgba(0,0,0,0.018) 75%),
    linear-gradient(45deg, rgba(0,0,0,0.018) 25%, transparent 25%, transparent 75%, rgba(0,0,0,0.018) 75%);
  background-size: 22px 22px; background-position: 0 0, 11px 11px;
}
.shot__glyph { font-size: 2.4rem; line-height: 1; }
.shot__cap { font-size: 0.85rem; }
.shot img { width: 100%; height: auto; border: 1px solid var(--line); border-radius: var(--radius); display: block; }

/* ===== Install guide ===== */
.guide { padding: 56px 0 84px; }
.guide__head { max-width: 720px; margin: 0 0 30px; }
.guide__title {
  font-size: clamp(2rem, 5vw, 3rem); line-height: 1.1;
  letter-spacing: -0.025em; margin: 0 0 16px; font-weight: 800;
}
.guide__sub { font-size: 1.12rem; color: var(--ink-soft); margin: 0; }

.prereq {
  display: flex; gap: 13px; align-items: flex-start;
  background: var(--bg-soft); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 16px 20px;
  font-size: 0.95rem; color: var(--ink-soft); margin: 0 0 40px; max-width: 760px;
}
.prereq__icon { font-size: 1.25rem; line-height: 1.4; flex: none; }
.prereq strong { color: var(--ink); }
.prereq code {
  font-family: var(--mono); font-size: 0.88em; background: rgba(37, 99, 214, 0.08);
  color: var(--accent-dark); padding: 1px 6px; border-radius: 5px;
}

/* the wizard */
.step__q { font-weight: 750; font-size: 1.2rem; letter-spacing: -0.01em; margin: 0 0 16px; }
.choices {
  display: grid; gap: 16px;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
}
.choice {
  text-align: left; background: var(--bg); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 20px 22px; cursor: pointer;
  font: inherit; color: var(--ink); display: flex; flex-direction: column; gap: 6px;
  transition: border-color 0.15s, box-shadow 0.15s, transform 0.06s;
}
.choice:hover { border-color: var(--accent); box-shadow: 0 12px 30px -20px rgba(37, 99, 214, 0.55); }
.choice:active { transform: translateY(1px); }
.choice.is-active { border-color: var(--accent); box-shadow: inset 0 0 0 1px var(--accent); }
.choice__icon { font-size: 1.7rem; line-height: 1; }
.choice__title { font-weight: 700; font-size: 1.06rem; display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.choice__desc { color: var(--ink-soft); font-size: 0.92rem; }
.pill {
  font-size: 0.66rem; font-weight: 700; letter-spacing: 0.05em; text-transform: uppercase;
  color: var(--accent); background: rgba(37, 99, 214, 0.1); padding: 3px 8px; border-radius: 999px;
}
.pill--soft { color: var(--ink-soft); background: var(--bg-soft); border: 1px solid var(--line); }

/* revealed panels */
.panel { margin-top: 30px; padding-top: 30px; border-top: 1px solid var(--line); max-width: 760px; }
.panel__h { font-size: 1.4rem; font-weight: 780; letter-spacing: -0.015em; margin: 0 0 12px; }
.panel p { color: var(--ink-soft); margin: 0 0 14px; }
.panel .term { margin: 18px 0; max-width: 100%; }

.steps { list-style: none; counter-reset: s; padding: 0; margin: 22px 0 0; }
.steps > li { position: relative; padding-left: 48px; margin-bottom: 26px; }
.steps > li::before {
  counter-increment: s; content: counter(s);
  position: absolute; left: 0; top: -2px; width: 32px; height: 32px;
  border-radius: 50%; background: var(--accent); color: #fff;
  font-weight: 700; font-size: 0.95rem;
  display: flex; align-items: center; justify-content: center;
}
.steps h4 { margin: 4px 0 6px; font-size: 1.06rem; font-weight: 700; }
.steps p { margin: 0 0 8px; }
.steps .term { margin: 12px 0 0; }

.note {
  font-size: 0.9rem; color: var(--ink-soft); background: var(--bg-soft);
  border-left: 3px solid var(--accent); border-radius: 0 8px 8px 0;
  padding: 12px 16px; margin: 16px 0 0;
}
.note strong { color: var(--ink); }

.startover {
  display: inline-flex; align-items: center; gap: 7px; margin-top: 6px;
  background: none; border: 0; font: inherit; font-size: 0.92rem;
  color: var(--accent); cursor: pointer; padding: 6px 0;
}
.startover:hover { text-decoration: underline; }

.help { margin-top: 44px; padding-top: 30px; border-top: 1px solid var(--line); max-width: 760px; }
.help h3 { font-size: 1.15rem; font-weight: 750; margin: 0 0 10px; }
.help p { color: var(--ink-soft); margin: 0; }

/* ===== Footer ===== */
.footer { background: var(--bg-soft); border-top: 1px solid var(--line); padding: 52px 0 28px; }
.footer__inner { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 40px; }
.footer__tag { color: var(--ink-soft); font-size: 0.92rem; margin: 14px 0 0; max-width: 260px; }
.footer__cols { display: flex; gap: 64px; flex-wrap: wrap; }
.footer__col h4 { font-size: 0.82rem; text-transform: uppercase; letter-spacing: 0.06em; color: var(--ink); margin: 0 0 12px; }
.footer__col a { display: block; color: var(--ink-soft); font-size: 0.95rem; margin-bottom: 8px; }
.footer__col a:hover { color: var(--ink); text-decoration: none; }
.footer__bar {
  display: flex; justify-content: space-between; flex-wrap: wrap; gap: 8px;
  margin-top: 44px; padding-top: 20px; border-top: 1px solid var(--line);
  color: var(--ink-soft); font-size: 0.85rem;
}

/* ===== Responsive ===== */
@media (max-width: 760px) {
  .nav__toggle { display: block; }
  .nav__links {
    display: none; position: absolute; top: 60px; left: 0; right: 0;
    flex-direction: column; align-items: flex-start; gap: 0;
    background: var(--bg); border-bottom: 1px solid var(--line); padding: 8px 24px 16px;
  }
  .nav__links.is-open { display: flex; }
  .nav__links a { width: 100%; padding: 11px 0; }
  .nav__gh { width: auto; margin-top: 6px; }

  .hero { padding: 56px 0 48px; }
  .row, .row--reverse { grid-template-columns: 1fr; gap: 22px; }
  .row--reverse .shot { order: 0; }
  .row { margin-bottom: 52px; }
}