/* Leitungsblitz
   Konzept: drei farbige Adern (Ping cyan, Download gelb, Upload pink) ziehen sich vom Logo
   über das Adern-Band bis in Kurve, Kennzahlen und Ablauf. Keine externen Fonts (DSGVO). */
:root {
  --bg: #eaf3ff;          /* helles Himmelblau */
  --bg-2: #d5e5fa;
  --panel: #0f2a6b;       /* tiefes Elektroblau */
  --panel-2: #1a3a8a;
  --panel-line: #2f4f9e;
  --text: #0f2a6b;
  --muted: #3e5688;
  --cyan: #22c7e6;        /* Ping */
  --volt: #ffc928;        /* Download */
  --pink: #ff4f86;        /* Upload */
  --on-panel: #f1f6ff;
  --on-panel-dim: #a9bce6;
  --on-volt: #0f2a6b;
  --font: Bahnschrift, "DIN Alternate", "DIN 2014", "Roboto Condensed", "Arial Narrow", system-ui, sans-serif;
  --body: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #081536; --bg-2: #13265a; --text: #eaf2ff; --muted: #a3b6e0;
    --panel: #0f2a6b; --panel-2: #1a3a8a; --panel-line: #2f4f9e;
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #081536; --bg-2: #13265a; --text: #eaf2ff; --muted: #a3b6e0;
  --panel: #0f2a6b; --panel-2: #1a3a8a; --panel-line: #2f4f9e;
  color-scheme: dark;
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--bg); color: var(--text); font: 17px/1.55 var(--body); overflow-x: hidden; }
a { color: inherit; text-underline-offset: .2em; }
:focus-visible { outline: 3px solid var(--pink); outline-offset: 3px; border-radius: 3px; }
.sr { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
.skip { position: absolute; left: 16px; top: -60px; background: var(--volt); color: var(--on-volt); padding: 8px 12px; z-index: 9; }
.skip:focus { top: 12px; }

main, .top, .foot { width: min(1120px, 100% - 32px); margin-inline: auto; }

/* Kopfzeile */
.top { display: flex; align-items: center; justify-content: space-between; gap: 16px; padding: 20px 0; }
.brand { display: inline-flex; align-items: center; gap: 12px; text-decoration: none; font: 700 1.4rem/1 var(--font); letter-spacing: .005em; color: var(--text); }
.brand svg { width: 64px; height: 32px; flex: none; }
.brand .bolt-edge { stroke: var(--bg); }
.top nav { display: flex; gap: 8px; font-family: var(--font); }
.top nav a { text-decoration: none; color: var(--text); padding: 8px 14px; border-radius: 999px; }
.top nav a:hover { background: var(--bg-2); }

/* Einleitung + Adern-Band */
.intro { padding: 30px 0 8px; max-width: 48rem; }
.intro h1 { font: 700 clamp(2.2rem, 5.6vw, 4.1rem)/1.03 var(--font); letter-spacing: -.012em; margin: 0 0 14px; text-wrap: balance; }
.intro p { margin: 0; color: var(--muted); font-size: 1.12rem; }

.strands { display: block; width: 100vw; margin-left: calc(50% - 50vw); height: 64px; margin-block: 18px -6px; }
.strands path { fill: none; stroke-width: 5; stroke-linecap: round; }
.strands .s1 { stroke: var(--cyan); }
.strands .s2 { stroke: var(--volt); }
.strands .s3 { stroke: var(--pink); }
@media (prefers-reduced-motion: no-preference) {
  .strands path { stroke-dasharray: 1; stroke-dashoffset: 1; animation: draw 1.4s cubic-bezier(.6, 0, .2, 1) forwards; }
  .strands .s2 { animation-delay: .12s; }
  .strands .s3 { animation-delay: .24s; }
  @keyframes draw { to { stroke-dashoffset: 0; } }
}

/* Messpanel */
.meter {
  position: relative;
  background:
    radial-gradient(120% 90% at 100% 0%, rgba(255, 79, 134, .22), transparent 55%),
    radial-gradient(90% 80% at 0% 100%, rgba(34, 199, 230, .2), transparent 60%),
    var(--panel);
  color: var(--on-panel);
  border-radius: 18px; padding: clamp(20px, 4vw, 44px);
  display: grid; gap: 22px;
  box-shadow: 0 24px 60px -30px rgba(15, 42, 107, .6);
}
.readout { display: flex; flex-wrap: wrap; align-items: flex-end; justify-content: space-between; gap: 8px 24px; }
.phase { margin: 0; font: 600 1.05rem var(--font); color: var(--on-panel-dim); display: inline-flex; align-items: center; gap: 10px; }
.phase::before { content: ""; width: 10px; height: 10px; border-radius: 50%; background: var(--on-panel-dim); }
.phase[data-tone="ping"] { color: var(--cyan); }
.phase[data-tone="down"] { color: var(--volt); }
.phase[data-tone="up"] { color: var(--pink); }
.phase[data-tone="error"] { color: #ff9b8a; }
.phase[data-tone]::before { background: currentColor; }
@media (prefers-reduced-motion: no-preference) {
  .meter[data-busy] .phase::before { animation: pulse 1s ease-in-out infinite; }
  @keyframes pulse { 50% { transform: scale(.5); opacity: .5; } }
}
.big { margin: 0; font: 700 clamp(4rem, 15vw, 9.5rem)/.82 var(--font); font-variant-numeric: tabular-nums; letter-spacing: -.02em; display: flex; align-items: baseline; gap: .12em; }
.big .unit { font-size: .2em; font-weight: 500; color: var(--on-panel-dim); letter-spacing: 0; }

.trace-wrap { position: relative; height: clamp(140px, 22vw, 220px); border-bottom: 1px solid var(--panel-line); }
#trace { position: absolute; inset: 0; width: 100%; height: 100%; }

.controls { display: flex; flex-wrap: wrap; align-items: center; gap: 14px 24px; }
.go {
  font: 700 1.15rem var(--font); letter-spacing: .01em;
  background: var(--volt); color: var(--on-volt); border: 0; border-radius: 999px;
  padding: 16px 34px; cursor: pointer; min-width: 210px;
  box-shadow: 0 0 0 0 rgba(255, 201, 40, .55);
  transition: background .15s, box-shadow .2s;
}
.go:hover { background: #ffd859; box-shadow: 0 0 0 6px rgba(255, 201, 40, .22); }
.go:active { transform: translateY(1px); }
.go[disabled] { background: var(--panel-2); color: var(--on-panel-dim); cursor: progress; box-shadow: none; }
.hint { margin: 0; color: var(--on-panel-dim); font-size: .95rem; max-width: 34rem; }

.results { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 12px; margin: 0; }
.r { padding: 16px 18px 14px; border-radius: 12px; background: rgba(255, 255, 255, .06); border-top: 4px solid var(--c); }
.r-ping { --c: var(--cyan); }
.r-down { --c: var(--volt); }
.r-up { --c: var(--pink); }
.r dt { font: 600 1rem var(--font); color: var(--c); }
.r dd { margin: 0; }
.r dd:nth-of-type(1) { font: 700 clamp(1.7rem, 4vw, 2.5rem)/1.15 var(--font); font-variant-numeric: tabular-nums; }
.r dd small { font-size: .45em; font-weight: 500; color: var(--on-panel-dim); }
.r .sub { color: var(--on-panel-dim); font-size: .9rem; min-height: 1.4em; }
.r .sub strong { color: var(--on-panel); font-weight: 600; }
.bar { height: 6px; border-radius: 3px; background: rgba(255, 255, 255, .1); margin-top: 8px; overflow: hidden; }
.bar i { display: block; height: 100%; width: 0; background: var(--c); border-radius: 3px; transition: width .6s ease; }
.ip { margin: 0; font-size: .9rem; color: var(--on-panel-dim); }
.ip span { color: var(--on-panel); font-variant-numeric: tabular-nums; }

/* Tarif */
.tarif { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 20px 56px; padding: 80px 0 24px; align-items: start; }
.tarif > * { min-width: 0; }
.tarif h2, .ablauf h2 { font: 700 clamp(1.7rem, 3.4vw, 2.4rem)/1.1 var(--font); margin: 0 0 12px; text-wrap: balance; }
.tarif-text p { margin: 0; color: var(--muted); max-width: 34rem; }
.tarif-form { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.tarif-form label { display: grid; gap: 6px; font: 600 .95rem var(--font); color: var(--muted); }
.field { display: flex; align-items: center; background: var(--bg-2); border-radius: 12px; border: 2px solid transparent; }
.field.f-down { border-bottom-color: var(--volt); }
.field.f-up { border-bottom-color: var(--pink); }
.field input { flex: 1; min-width: 0; width: 100%; background: transparent; border: 0; padding: 12px 14px; font: 700 1.4rem var(--font); color: var(--text); font-variant-numeric: tabular-nums; }
.field input:focus { outline: none; }
.field:focus-within { border-color: var(--text); }
.field span { padding-right: 14px; color: var(--muted); font-family: var(--font); }
.note { grid-column: 1 / -1; margin: 6px 0 0; font-size: .92rem; color: var(--muted); max-width: 52rem; }

/* Ablauf – echte Reihenfolge; Farben = Messgrößen */
.ablauf { padding: 64px 0 80px; }
.ablauf ol { list-style: none; counter-reset: s; padding: 0; margin: 28px 0 0; display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 28px; }
.ablauf li { counter-increment: s; border-top: 5px solid var(--c); padding-top: 14px; }
.ablauf li:nth-child(1) { --c: var(--cyan); }
.ablauf li:nth-child(2) { --c: var(--volt); }
.ablauf li:nth-child(3) { --c: var(--pink); }
.ablauf li::before { content: counter(s); display: inline-grid; place-items: center; width: 44px; height: 44px; border-radius: 50%; background: var(--c); color: var(--on-volt); font: 700 1.4rem/1 var(--font); }
.ablauf h3 { font: 700 1.25rem var(--font); margin: 12px 0 6px; }
.ablauf li p { margin: 0; color: var(--muted); }
.fine { margin: 32px 0 0; font-size: .92rem; color: var(--muted); max-width: 52rem; }

/* Rechtsseiten */
.legal { padding: 24px 0 80px; }
.legal > * { max-width: 46rem; }
.legal ul { padding-left: 1.2em; }
.legal h1 { font: 700 clamp(2rem, 5vw, 3rem)/1.05 var(--font); margin: 10px 0 24px; }
.legal h2 { font: 700 1.35rem var(--font); margin: 36px 0 8px; }
.legal .todo { background: var(--volt); color: var(--on-volt); padding: 0 4px; border-radius: 3px; }

.foot { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 12px; padding: 28px 0 40px; border-top: 1px solid var(--bg-2); font-family: var(--font); color: var(--muted); }
.foot p { margin: 0; display: flex; align-items: center; gap: 10px; }
.foot p svg { width: 40px; height: 20px; }
.foot nav { display: flex; gap: 22px; }

@media (max-width: 760px) {
  .top nav { display: none; }
  .results { grid-template-columns: 1fr; }
  .tarif { grid-template-columns: 1fr; padding-top: 56px; }
  .ablauf ol { grid-template-columns: 1fr; }
  .go { width: 100%; }
  .strands { height: 44px; }
}
@media (prefers-reduced-motion: reduce) {
  *, *::before { transition: none !important; animation: none !important; }
}