/* open-co.de — Palette: #2b4570 #4167a6 #8da9c4 #a8d0db #eef4ed */
:root {
  --bg: #ffffff;
  --bg-soft: #f5f8f4;
  --text: #15233b;
  --muted: #56627a;
  --line: #e2e8ef;
  --brand: #2b4570;
  --accent: #4167a6;
  --logo-fill: #8da9c4;
  --logo-stroke: #2b4570;
  --tint: #eaf1f8;
  --tint-strong: #c9d8e8;
  --wrap: 68rem;
  --radius: 10px;
  --font: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0e1626;
    --bg-soft: #131d31;
    --text: #e8eef5;
    --muted: #9aa8bd;
    --line: #233149;
    --brand: #a8d0db;
    --accent: #8db4e8;
    --logo-fill: #8da9c4;
    --logo-stroke: #a8d0db;
    --tint: #18243b;
    --tint-strong: #2a3a57;
  }
}

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

html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 400 1.0625rem/1.65 var(--font);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a { color: var(--accent); text-underline-offset: .2em; text-decoration-thickness: 1px; }
a:hover { color: var(--brand); }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 2px; }

h1, h2, h3 { color: var(--text); line-height: 1.15; letter-spacing: -.02em; font-weight: 650; margin: 0; }

.wrap { width: 100%; max-width: var(--wrap); margin: 0 auto; padding: 0 1.5rem; }

.skip { position: absolute; left: -999px; top: .5rem; background: var(--bg); padding: .5rem 1rem; z-index: 10; }
.skip:focus { left: .5rem; }

/* Header */
.site-header { border-bottom: 1px solid var(--line); }
.header-inner { display: flex; align-items: center; justify-content: space-between; gap: 1rem; height: 4.25rem; }
.brand { display: inline-flex; align-items: center; gap: .6rem; color: var(--text); text-decoration: none; font-weight: 650; letter-spacing: -.01em; }
.brand:hover { color: var(--text); }
.logo { width: 1.6rem; height: 1.6rem; fill: var(--logo-fill); stroke: var(--logo-stroke); stroke-width: 2; stroke-miterlimit: 10; flex: none; }
.nav { display: flex; gap: 1.75rem; }
.nav a { color: var(--muted); text-decoration: none; font-size: .95rem; }
.nav a:hover { color: var(--text); }

/* Hero */
.hero { padding: clamp(4.5rem, 12vw, 9rem) 0 clamp(4rem, 10vw, 7rem); }
.eyebrow { font: 500 .8rem/1 var(--mono); letter-spacing: .08em; text-transform: uppercase; color: var(--accent); margin: 0 0 1.5rem; }
.hero h1 { font-size: clamp(2.4rem, 6vw, 4.25rem); max-width: 18ch; }
.lead { font-size: clamp(1.1rem, 2vw, 1.3rem); color: var(--muted); max-width: 40rem; margin: 1.5rem 0 0; }
.actions { display: flex; flex-wrap: wrap; gap: .75rem; margin-top: 2.5rem; }
.btn { display: inline-flex; align-items: center; height: 2.9rem; padding: 0 1.35rem; border-radius: 999px; font-weight: 550; font-size: .97rem; text-decoration: none; border: 1px solid var(--line); color: var(--text); transition: border-color .15s, background .15s; }
.btn:hover { border-color: var(--muted); color: var(--text); }
.btn-primary { background: var(--brand); border-color: var(--brand); color: var(--bg); }
.btn-primary:hover { background: var(--accent); border-color: var(--accent); color: var(--bg); }

/* Sections */
.section { padding: clamp(4rem, 9vw, 6.5rem) 0; border-top: 1px solid var(--line); }
.section-head { display: grid; gap: 1rem; margin-bottom: 3rem; max-width: 40rem; }
.section-head h2 { font-size: clamp(1.75rem, 3.5vw, 2.4rem); }
.section-head p { color: var(--muted); margin: 0; }

.topics { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(auto-fit, minmax(15rem, 1fr)); border-top: 1px solid var(--line); border-left: 1px solid var(--line); }
.topic { padding: 2rem 1.75rem 2.25rem; border-right: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.topic-no { font: 500 .8rem/1 var(--mono); color: var(--accent); }
.topic h3 { font-size: 1.25rem; margin: 1.5rem 0 .6rem; }
.topic p { color: var(--muted); margin: 0 0 1.25rem; font-size: .98rem; }
.tags { list-style: none; margin: 0; padding: 0; display: flex; flex-wrap: wrap; gap: .4rem; }
.tags li { font-size: .8rem; padding: .2rem .65rem; border-radius: 999px; background: var(--bg-soft); color: var(--muted); border: 1px solid var(--line); }

/* Icons */
.icon { width: 1.25rem; height: 1.25rem; fill: none; stroke: currentColor; stroke-width: 1.6; stroke-linecap: round; stroke-linejoin: round; flex: none; }
.btn .icon { width: 1.05rem; height: 1.05rem; margin-left: .5rem; transition: transform .15s; }
.btn-primary:hover .icon { transform: translateX(2px); }
.btn:not(.btn-primary):hover .icon { transform: translateY(2px); }
.icon-badge { display: inline-grid; place-items: center; width: 2.75rem; height: 2.75rem; border-radius: 12px; background: var(--tint); color: var(--accent); flex: none; }

/* Hero mark */
.hero-inner { display: grid; grid-template-columns: minmax(0, 1fr) auto; align-items: center; gap: 3rem; }
.hero-mark .logo { width: clamp(12rem, 24vw, 19rem); height: auto; fill: var(--tint); stroke: var(--tint-strong); stroke-width: .6; }
@media (max-width: 56rem) { .hero-inner { grid-template-columns: 1fr; } .hero-mark { display: none; } }

/* Principles */
.principles { border-top: 1px solid var(--line); background: var(--bg-soft); }
.principle-list { list-style: none; margin: 0; padding: 2rem 0; display: grid; grid-template-columns: repeat(auto-fit, minmax(15rem, 1fr)); gap: 1.5rem 2.5rem; }
.principle-list li { display: flex; align-items: center; gap: 1rem; }
.principle-list strong { display: block; font-weight: 600; font-size: .98rem; }
.principle-list span:not(.icon-badge) { display: block; color: var(--muted); font-size: .9rem; }
.principles .icon-badge { background: var(--bg); border: 1px solid var(--line); }

.topic { transition: background .2s; }
.topic:hover { background: var(--bg-soft); }
.topic-top { display: flex; justify-content: space-between; align-items: flex-start; }
.section-head .eyebrow { margin: 0; }
.section-soft { background: var(--bg-soft); }

.contact { display: grid; grid-template-columns: repeat(auto-fit, minmax(16rem, 1fr)); gap: 2.5rem; align-items: end; }
.contact-list { list-style: none; padding: 0; margin: 0; display: grid; grid-template-columns: repeat(auto-fit, minmax(14rem, 1fr)); gap: 1.75rem 2rem; }
.contact-list > li { display: grid; grid-template-columns: auto 1fr; column-gap: .9rem; align-content: start; }
.contact-list .icon { grid-row: span 2; color: var(--accent); margin-top: .1rem; }
.contact-list .label { display: block; font: 500 .75rem/1 var(--mono); text-transform: uppercase; letter-spacing: .08em; color: var(--muted); margin-bottom: .4rem; }
.contact-list .value { margin: 0; font-size: 1.05rem; }
.contact-list .value a { color: var(--text); text-decoration: none; border-bottom: 1px solid var(--line); }
.contact-list .value a:hover { border-color: var(--text); }

/* Pages */
.page { padding: clamp(3.5rem, 8vw, 6rem) 1.5rem clamp(4rem, 9vw, 7rem); max-width: 46rem; }
.page-header { margin-bottom: 2.5rem; }
.page-header h1 { font-size: clamp(2rem, 5vw, 3rem); }
.prose h2 { font-size: 1.2rem; margin: 2.5rem 0 .75rem; }
.prose p, .prose ul { margin: 0 0 1rem; }
.prose address { font-style: normal; }
.prose .note { font-size: .9rem; color: var(--muted); }
.center { text-align: center; }

/* Footer */
.site-footer { border-top: 1px solid var(--line); font-size: .9rem; color: var(--muted); }
.footer-inner { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 1rem; padding-top: 2rem; padding-bottom: 2rem; }
.footer-inner p { margin: 0; }
.site-footer nav { display: flex; gap: 1.5rem; }
.site-footer a { color: var(--muted); text-decoration: none; }
.site-footer a:hover { color: var(--text); }

@media (max-width: 34rem) {
  .nav { gap: 1.1rem; }
  .nav a:nth-child(1) { display: none; }
  .wrap { padding: 0 1rem; }
  .page { padding-left: 1rem; padding-right: 1rem; }
}
.prose .with-icon .icon { vertical-align: -.2em; margin-right: .35rem; }
.prose .with-icon .icon { width: 1.1rem; height: 1.1rem; color: var(--accent); }