/* Informatik Klasse 9 – Kurswebsite
   Selbsttragend, keine externen Abhängigkeiten. */

:root {
  --bg: #f6f7f9;
  --surface: #ffffff;
  --surface-2: #eef1f5;
  --text: #1c2430;
  --muted: #5a6675;
  --border: #d9dee6;
  --accent: #1f7a8c;
  --accent-soft: #e3f1f4;
  --accent-strong: #145b6a;
  --note: #2563a8;
  --note-soft: #e5eefb;
  --tip: #2f8f4e;
  --tip-soft: #e4f4e9;
  --warn: #b26a00;
  --warn-soft: #fbeed6;
  --code-bg: #1e2733;
  --code-text: #e6edf3;
  --shadow: 0 1px 2px rgba(20,30,45,.06), 0 4px 16px rgba(20,30,45,.06);
  --radius: 12px;
  --maxw: 860px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #10151b;
    --surface: #182029;
    --surface-2: #1f2932;
    --text: #e7ecf2;
    --muted: #9aa7b4;
    --border: #2a3644;
    --accent: #4fb3c7;
    --accent-soft: #16323a;
    --accent-strong: #7fd0e0;
    --note: #6ba6e6;
    --note-soft: #16273b;
    --tip: #6cc785;
    --tip-soft: #16301f;
    --warn: #e0a44a;
    --warn-soft: #33260f;
    --code-bg: #0d141c;
    --code-text: #dce6f0;
    --shadow: 0 1px 2px rgba(0,0,0,.3), 0 6px 20px rgba(0,0,0,.35);
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  line-height: 1.65;
  font-size: 17px;
  -webkit-text-size-adjust: 100%;
}

/* ---------- Kopf / Navigation ---------- */
.site-header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 20;
}
.nav {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  align-items: center;
  gap: 8px 22px;
  flex-wrap: wrap;
  min-height: 58px;
}
.brand {
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
  margin-right: auto;
  font-size: 1.02rem;
  letter-spacing: .2px;
}
.brand span { color: var(--accent); }
.nav a.navlink {
  color: var(--muted);
  text-decoration: none;
  font-size: .95rem;
  font-weight: 500;
  padding: 4px 2px;
  border-bottom: 2px solid transparent;
}
.nav a.navlink:hover { color: var(--text); }
.nav a.navlink.active {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

/* ---------- Inhaltscontainer ---------- */
main {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 36px 20px 80px;
}

.page-intro { margin-bottom: 30px; }

h1 {
  font-size: 2rem;
  line-height: 1.2;
  margin: 0 0 .35em;
  letter-spacing: -.3px;
}
h2 {
  font-size: 1.4rem;
  margin: 2em 0 .6em;
  padding-top: .2em;
  letter-spacing: -.2px;
}
h3 { font-size: 1.12rem; margin: 1.6em 0 .5em; }
p { margin: .7em 0; }

a { color: var(--accent); }
a:hover { color: var(--accent-strong); }

.lead { font-size: 1.12rem; color: var(--muted); }

.eyebrow {
  text-transform: uppercase;
  letter-spacing: 1.5px;
  font-size: .74rem;
  font-weight: 700;
  color: var(--accent);
  margin: 0 0 .5em;
}

code {
  font-family: "SFMono-Regular", "JetBrains Mono", "Fira Code", Consolas, monospace;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 5px;
  padding: .08em .4em;
  font-size: .9em;
}
pre {
  background: var(--code-bg);
  color: var(--code-text);
  padding: 14px 16px;
  border-radius: 10px;
  overflow-x: auto;
  font-size: .92rem;
  line-height: 1.5;
}
pre code {
  background: none;
  border: none;
  padding: 0;
  color: inherit;
  font-size: inherit;
}

/* ---------- Karten (Startseite) ---------- */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 18px;
  margin: 28px 0;
}
.card {
  display: block;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px 22px 20px;
  text-decoration: none;
  color: var(--text);
  box-shadow: var(--shadow);
  transition: transform .12s ease, border-color .12s ease;
}
.card:hover { transform: translateY(-2px); border-color: var(--accent); }
.card .kicker { font-size: .78rem; font-weight: 700; color: var(--accent); text-transform: uppercase; letter-spacing: 1px; }
.card h3 { margin: .35em 0 .3em; font-size: 1.18rem; }
.card p { margin: 0; color: var(--muted); font-size: .95rem; }

/* ---------- Hinweisboxen ---------- */
.box {
  border: 1px solid var(--border);
  border-left-width: 4px;
  border-radius: 10px;
  padding: 14px 18px;
  margin: 1.3em 0;
  background: var(--surface);
}
.box .box-title { font-weight: 700; margin: 0 0 .3em; font-size: .96rem; }
.box p:last-child { margin-bottom: 0; }
.box.note { border-left-color: var(--note); background: var(--note-soft); }
.box.note .box-title { color: var(--note); }
.box.tip  { border-left-color: var(--tip);  background: var(--tip-soft); }
.box.tip .box-title { color: var(--tip); }
.box.warn { border-left-color: var(--warn); background: var(--warn-soft); }
.box.warn .box-title { color: var(--warn); }

/* ---------- Aufgabe / Lösung ---------- */
.aufgabe {
  background: var(--accent-soft);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 16px 18px;
  margin: 1.4em 0;
}
.aufgabe > .box-title { color: var(--accent-strong); font-weight: 700; margin: 0 0 .3em; }

details.loesung {
  margin-top: .9em;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--surface);
  overflow: hidden;
}
details.loesung > summary {
  cursor: pointer;
  padding: 9px 14px;
  font-weight: 600;
  font-size: .92rem;
  color: var(--accent);
  list-style: none;
  user-select: none;
}
details.loesung > summary::-webkit-details-marker { display: none; }
details.loesung > summary::before { content: "▸ "; }
details.loesung[open] > summary::before { content: "▾ "; }
details.loesung > summary:hover { color: var(--accent-strong); }
details.loesung .loesung-body { padding: 4px 16px 14px; border-top: 1px solid var(--border); }

/* ---------- Tabellen ---------- */
.table-wrap { overflow-x: auto; margin: 1.2em 0; }
table {
  border-collapse: collapse;
  width: 100%;
  font-size: .95rem;
  background: var(--surface);
  border-radius: 8px;
  overflow: hidden;
}
th, td {
  text-align: left;
  padding: 9px 12px;
  border-bottom: 1px solid var(--border);
}
th { background: var(--surface-2); font-weight: 600; }
tr:last-child td { border-bottom: none; }

/* ---------- Downloads ---------- */
.downloads { list-style: none; padding: 0; margin: 1.2em 0; display: grid; gap: 8px; }
.downloads li { margin: 0; }
.downloads a {
  display: flex;
  align-items: center;
  gap: 10px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 14px;
  text-decoration: none;
  color: var(--text);
}
.downloads a:hover { border-color: var(--accent); }
.downloads .ext {
  font-size: .72rem;
  font-weight: 700;
  letter-spacing: .5px;
  color: #fff;
  background: var(--accent);
  border-radius: 5px;
  padding: 2px 7px;
  text-transform: uppercase;
}
.downloads .fname { flex: 1; }
.downloads .fsize { color: var(--muted); font-size: .85rem; }

/* ---------- Diagramm-Hilfen ---------- */
.ip-boxes { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; margin: 1em 0; font-family: "SFMono-Regular", Consolas, monospace; }
.octet { background: var(--accent-soft); border: 1px solid var(--accent); color: var(--accent-strong); border-radius: 8px; padding: 8px 14px; font-weight: 700; font-size: 1.15rem; }
.dot { font-weight: 700; font-size: 1.3rem; color: var(--muted); }

.flow { display: grid; gap: 0; margin: 1.3em 0; counter-reset: step; }
.flow-step { position: relative; padding: 10px 14px 14px 46px; }
.flow-step:not(:last-child)::after { content:""; position:absolute; left:19px; top:34px; bottom:-6px; width:2px; background:var(--border); }
.flow-step::before {
  counter-increment: step; content: counter(step);
  position: absolute; left: 8px; top: 8px;
  width: 24px; height: 24px; border-radius: 50%;
  background: var(--accent); color: #fff; font-size: .85rem; font-weight: 700;
  display: flex; align-items: center; justify-content: center;
}
.flow-step strong { display:block; }

/* ---------- Fuß ---------- */
.site-footer {
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: .88rem;
  text-align: center;
  padding: 26px 20px 40px;
}

/* Sprungmarke oben */
.back-top { display:inline-block; margin-top: 2em; font-size:.9rem; }

hr { border: none; border-top: 1px solid var(--border); margin: 2em 0; }

@media (max-width: 560px) {
  body { font-size: 16px; }
  h1 { font-size: 1.65rem; }
  main { padding: 26px 16px 60px; }
  .nav { padding: 0 16px; }
}