/* ═══════════════════════════════════════════════════════════════
   UFR Corporate Design Stylesheet — Clock Networks Lab
   Based on: cd.uni-freiburg.de (introduced Feb 2023, Moniteurs)

   Typography:  "Social" (licensed) / "Arial" (everyday fallback)
                All text: left-aligned ragged-right (Flattersatz)
                Scale: 100% base | 150% intro | 200% sub | 400% headline

   Colour canon:
     Haupt:     Blau #344A9A | Schwarz #000000 | Weiß #FFFFFF
     Dunkelblau:#00004A
     Blau steps:100% #344A9A | 80% #5D6BAD | 60% #868DC2
                40% #AFB1D8 | 20% #D7D8EC
     Sand:      100% #F6F1E3 | 50% #FAF8F1
     Zusatz:    Grün #00A082 | Braun #8F6B30 | Gelb #FFE863 | Rosa #F5C2ED

   Contrast: min 4.5:1
   Layout:   Quadrant Grid — adaptive, left-aligned, generous whitespace
   ═══════════════════════════════════════════════════════════════ */

:root {
  --ufr-blau:        #344A9A;
  --ufr-schwarz:     #000000;
  --ufr-weiss:       #FFFFFF;
  --ufr-blau-80:     #5D6BAD;
  --ufr-blau-60:     #868DC2;
  --ufr-blau-40:     #AFB1D8;
  --ufr-blau-20:     #D7D8EC;
  --ufr-dunkelblau:  #00004A;
  --ufr-sand-100:    #F6F1E3;
  --ufr-sand-50:     #FAF8F1;
  --ufr-gruen:       #00A082;
  --ufr-braun:       #8F6B30;
  --ufr-gelb:        #FFE863;
  --ufr-rosa:        #F5C2ED;

  --color-primary:       var(--ufr-blau);
  --color-primary-dark:  var(--ufr-dunkelblau);
  --color-bg:            var(--ufr-weiss);
  --color-bg-warm:       var(--ufr-sand-50);
  --color-bg-accent:     var(--ufr-sand-100);
  --color-text:          var(--ufr-schwarz);
  --color-text-secondary:#3a3a3a;
  --color-border:        var(--ufr-blau-20);
  --color-danger:        #9b1b30;
  --color-danger-bg:     #fdf0f0;
  --color-warning:       var(--ufr-braun);
  --color-warning-bg:    #fdf6ee;

  --font-body:     Arial, "Helvetica Neue", Helvetica, sans-serif;
  --font-display:  Arial, "Helvetica Neue", Helvetica, sans-serif;
  --font-mono:     "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;

  --fs-base:       1rem;
  --fs-intro:      1.5rem;
  --fs-sub:        2rem;
  --fs-headline:   2.5rem;
  --nav-height:    52px;
  --content-max:   860px;
  --grid-gap:      24px;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; scroll-padding-top: calc(var(--nav-height) + 24px); }

body {
  font-family: var(--font-body);
  font-size: var(--fs-base);
  line-height: 1.65;
  color: var(--color-text);
  background: var(--color-bg);
  text-align: left;
}

/* ── Navigation ── */
nav {
  position: sticky; top: 0; z-index: 100;
  background: var(--color-primary); color: var(--ufr-weiss);
  height: var(--nav-height); display: flex; align-items: center;
  padding: 0 var(--grid-gap);
  box-shadow: 0 1px 4px rgba(0,0,0,0.12);
}
nav .nav-brand {
  font-family: var(--font-display); font-size: 1.05rem; font-weight: 700;
  white-space: nowrap; margin-right: 28px;
  text-decoration: none; color: var(--ufr-weiss);
}
nav .nav-links { display: flex; gap: 4px; overflow-x: auto; }
nav .nav-links a {
  color: rgba(255,255,255,0.78); text-decoration: none;
  font-size: 0.85rem; padding: 6px 12px; border-radius: 3px;
  white-space: nowrap; transition: background 0.15s, color 0.15s;
}
nav .nav-links a:hover, nav .nav-links a.active {
  background: rgba(255,255,255,0.15); color: var(--ufr-weiss);
}

/* ── Hero ── */
.hero {
  background: linear-gradient(135deg, var(--color-primary-dark) 0%, var(--color-primary) 100%);
  color: var(--ufr-weiss); padding: 72px var(--grid-gap) 52px; text-align: left;
}
.hero-inner { max-width: var(--content-max); margin: 0 auto; }
.hero h1 {
  font-family: var(--font-display);
  font-size: clamp(1.8rem, 4vw, var(--fs-headline));
  font-weight: 700; line-height: 1.15;
}
.hero .subtitle {
  font-size: var(--fs-intro); font-weight: 400; opacity: 0.88;
  margin-top: 8px; line-height: 1.35;
}
.hero .meta { font-size: 0.92rem; opacity: 0.68; margin-top: 16px; }
.hero .draft-badge {
  display: inline-block; margin-top: 20px; padding: 5px 16px;
  border: 1px solid rgba(255,255,255,0.3); border-radius: 2px;
  font-size: 0.75rem; font-weight: 700; letter-spacing: 0.08em;
  text-transform: uppercase; opacity: 0.7;
}

/* ── Container ── */
.container { max-width: var(--content-max); margin: 0 auto; padding: 40px var(--grid-gap) 80px; }

/* ── Typography ── */
h1, h2, h3, h4 {
  font-family: var(--font-display); color: var(--color-primary-dark);
  line-height: 1.25; text-align: left;
}
h2 {
  font-size: clamp(1.35rem, 2.5vw, 1.6rem); font-weight: 700;
  margin-top: 56px; margin-bottom: 16px; padding-bottom: 10px;
  border-bottom: 3px solid var(--ufr-blau-20);
}
h3 { font-size: 1.15rem; font-weight: 700; margin-top: 36px; margin-bottom: 10px; color: var(--color-primary); }
h4 { font-size: 1rem; font-weight: 700; margin-top: 24px; margin-bottom: 8px; }
p { margin-bottom: 14px; }
strong { font-weight: 700; }
a { color: var(--color-primary); text-decoration: underline; text-underline-offset: 2px; }
a:hover { color: var(--color-primary-dark); }

/* ── Part dividers ── */
.part-divider {
  margin-top: 64px; margin-bottom: 24px; padding: 20px 24px;
  background: var(--color-bg-accent); border-left: 4px solid var(--color-primary);
  border-radius: 0 4px 4px 0;
}
.part-divider h2 { margin: 0 0 4px; padding: 0; border: none; font-size: 1.4rem; }
.part-divider p { margin: 0; font-size: 0.92rem; color: var(--color-text-secondary); font-style: italic; }

/* ── Tables ── */
table { width: 100%; border-collapse: collapse; margin: 16px 0 24px; font-size: 0.9rem; }
thead th {
  background: var(--color-primary); color: var(--ufr-weiss); font-weight: 700;
  text-align: left; padding: 10px 14px; font-size: 0.84rem;
}
thead th:first-child { border-radius: 3px 0 0 0; }
thead th:last-child  { border-radius: 0 3px 0 0; }
tbody td { padding: 10px 14px; border-bottom: 1px solid var(--color-border); vertical-align: top; }
tbody tr:last-child td { border-bottom: none; }
tbody tr:nth-child(even) { background: var(--color-bg-warm); }

/* ── Callouts ── */
.callout { padding: 16px 20px; border-radius: 3px; margin: 20px 0; font-size: 0.92rem; line-height: 1.6; }
.callout-warning { background: var(--color-warning-bg); border-left: 4px solid var(--color-warning); }
.callout-warning strong { color: var(--color-warning); }
.callout-danger { background: var(--color-danger-bg); border-left: 4px solid var(--color-danger); }
.callout-danger strong { color: var(--color-danger); }
.callout-note { background: var(--ufr-blau-20); border-left: 4px solid var(--ufr-blau-60); }

/* ── Lists ── */
ul, ol { margin: 8px 0 16px 24px; }
li { margin-bottom: 6px; }
li ul, li ol { margin-top: 6px; margin-bottom: 6px; }

/* ── Step badges ── */
.step-badge {
  display: inline-block; background: var(--color-primary); color: var(--ufr-weiss);
  font-size: 0.75rem; font-weight: 700; padding: 2px 10px; border-radius: 2px;
  margin-right: 8px; vertical-align: middle;
}

/* ── Code ── */
code {
  font-family: var(--font-mono); font-size: 0.88em;
  background: var(--ufr-blau-20); padding: 2px 6px; border-radius: 3px;
}
pre {
  background: var(--color-primary-dark); color: var(--ufr-blau-20);
  padding: 20px 24px; border-radius: 4px; overflow-x: auto;
  font-family: var(--font-mono); font-size: 0.85rem; line-height: 1.55;
  margin: 16px 0 24px;
}
pre code { background: none; padding: 0; color: inherit; }

/* ── Math blocks ── */
.math-block {
  background: var(--color-bg-warm); border-left: 4px solid var(--ufr-blau-40);
  padding: 16px 20px; margin: 20px 0; border-radius: 0 4px 4px 0;
  font-family: var(--font-mono); font-size: 0.95rem; line-height: 1.7;
  overflow-x: auto;
}

/* ── Card grid (for index page) ── */
.card-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 16px; margin: 24px 0; }
.card {
  background: var(--color-bg-warm); border: 1px solid var(--color-border);
  border-radius: 4px; padding: 20px; text-decoration: none; color: var(--color-text);
  transition: border-color 0.15s, box-shadow 0.15s;
}
.card:hover { border-color: var(--color-primary); box-shadow: 0 2px 8px rgba(52,74,154,0.12); }
.card h3 { margin-top: 0; font-size: 1.05rem; }
.card p { font-size: 0.88rem; color: var(--color-text-secondary); margin-bottom: 0; }

hr { border: none; height: 1px; background: var(--color-border); margin: 40px 0; }

/* ── Footer ── */
footer {
  background: var(--color-bg-accent); text-align: left;
  padding: 28px var(--grid-gap); font-size: 0.82rem; color: var(--color-text-secondary);
  border-top: 3px solid var(--color-primary);
}
footer .footer-inner { max-width: var(--content-max); margin: 0 auto; }
footer a { color: var(--color-primary); text-decoration: none; }
footer a:hover { text-decoration: underline; }
footer .footer-cd-note { margin-top: 8px; font-size: 0.76rem; color: var(--ufr-blau-60); }

/* ── Responsive ── */
@media (max-width: 640px) {
  nav { padding: 0 12px; }
  nav .nav-brand { font-size: 0.92rem; margin-right: 12px; }
  nav .nav-links a { font-size: 0.78rem; padding: 5px 8px; }
  .hero { padding: 40px 16px 32px; }
  .hero .subtitle { font-size: 1.15rem; }
  .container { padding: 24px 16px 60px; }
  table { font-size: 0.82rem; }
  thead th, tbody td { padding: 8px 10px; }
  .card-grid { grid-template-columns: 1fr; }
}

@media print {
  nav, .hero .draft-badge { display: none; }
  .hero { background: none !important; color: var(--color-text); padding: 24px 0; }
  .container { max-width: 100%; }
  .callout, table { break-inside: avoid; }
}