/* ==========================================================================
   stunde.tibil.de – Präsentation KI
   Hintergrund und Farben wie www.tibil.de: Türkis + Orange auf fast Schwarz
   ========================================================================== */

:root {
  --bg: #03080d;
  --ink: #dbf6f8;
  --muted: #8db3ba;

  --teal: #19c3d1;
  --teal-hi: #9df3f7;
  --teal-line: rgba(157, 243, 247, 0.18);
  --orange: #ff7a1a;
  --orange-hi: #ffc27a;

  /* Chrom-Effekt wie die Überschriften auf tibil.de */
  --metal-teal: linear-gradient(180deg,
    #f4feff 0%, #a6f4f8 20%, #2ec4d1 44%, #0a5462 51%,
    #1fa9b7 58%, #8ff0f5 78%, #d9fdff 90%, #4cc9d3 100%);
  --metal-orange: linear-gradient(180deg,
    #fff3e3 0%, #ffc98a 22%, #ff8a2a 45%, #7a2e00 52%,
    #e8691a 60%, #ffb468 80%, #ffe0bd 92%, #ff9440 100%);

  --panel: linear-gradient(160deg, rgba(16, 40, 50, 0.74), rgba(4, 12, 18, 0.86));
  /* Folienfläche etwas durchsichtiger, damit die Platine durchscheint */
  --folie-bg: linear-gradient(160deg, rgba(16, 40, 50, 0.6), rgba(4, 12, 18, 0.74));
  --radius: 14px;

  --font-display: "Michroma", "Segoe UI", Arial, sans-serif;
  --font-body: "Rajdhani", "Segoe UI", Arial, sans-serif;
  --font-mono: "JetBrains Mono", Consolas, "Courier New", monospace;

  --steuer-h: 110px;   /* Platz unten für die Pfeile */
}

* { box-sizing: border-box; }

html { color-scheme: dark; height: 100%; }

body {
  margin: 0;
  height: 100%;
  overflow: hidden;
  background:
    radial-gradient(1200px 700px at 12% -10%, rgba(25, 195, 209, 0.16), transparent 60%),
    radial-gradient(1000px 700px at 100% 110%, rgba(255, 122, 26, 0.12), transparent 60%),
    var(--bg);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: clamp(18px, 1.6vw, 26px);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

/* Animierte Platine im Hintergrund (js/hintergrund.js) */
#bg {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
  pointer-events: none;
}

/* Feine Scanlines + dunkle Ränder wie auf tibil.de */
body::after {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  background:
    radial-gradient(ellipse 90% 85% at 50% 45%, transparent 55%, rgba(0, 2, 6, 0.6) 100%),
    repeating-linear-gradient(0deg, rgba(255, 255, 255, 0.018) 0 1px, transparent 1px 3px);
}

/* --------------------------------------------------------------------------
   Folien
   -------------------------------------------------------------------------- */
.folien {
  position: fixed;
  inset: 0 0 var(--steuer-h) 0;
  z-index: 2;
}

.folie {
  position: absolute;
  inset: clamp(16px, 4vh, 48px) clamp(16px, 5vw, 80px) 0;
  max-width: 1200px;
  margin: 0 auto;
  padding: clamp(20px, 4vh, 48px) clamp(20px, 4vw, 56px);
  display: flex;
  flex-direction: column;
  justify-content: flex-start;
  overflow-y: auto;

  background: var(--folie-bg);
  border: 1px solid var(--teal-line);
  border-radius: var(--radius);
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.45), inset 0 1px 0 rgba(157, 243, 247, 0.08);
  backdrop-filter: blur(3px);

  opacity: 0;
  visibility: hidden;
  transform: translateX(40px);
  transition: opacity 0.45s ease, transform 0.45s ease, visibility 0s linear 0.45s;
}

.folie.ist-aktiv {
  opacity: 1;
  visibility: visible;
  transform: none;
  transition: opacity 0.45s ease, transform 0.45s ease, visibility 0s;
}

/* Beim Zurückblättern kommt die Folie von links */
.folie.von-links { transform: translateX(-40px); }

.folie h2 {
  margin: 0 0 0.9em;
  font-family: var(--font-display);
  font-weight: 400;
  font-size: clamp(22px, 3vw, 44px);
  line-height: 1.25;
  letter-spacing: 0.02em;
  background: var(--metal-teal);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.folie p { margin: 0 0 0.8em; max-width: 60ch; }

/* Titelfolie: Inhalt in der Mitte */
.folie--titel { align-items: center; justify-content: center; text-align: center; }

.kicker {
  font-family: var(--font-mono);
  font-size: 0.75em;
  letter-spacing: 0.3em;
  text-transform: uppercase;
  color: var(--orange-hi);
}

.titel {
  margin: 0.2em 0 0.4em;
  font-family: var(--font-display);
  font-weight: 400;
  font-size: clamp(30px, 6vw, 88px);
  line-height: 1.15;
  background: var(--metal-teal);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  filter: drop-shadow(0 0 18px rgba(25, 195, 209, 0.35));
}

.untertitel {
  font-size: 1.15em;
  color: var(--muted);
  margin-left: auto;
  margin-right: auto;
}

/* Aufzählungen */
.liste { margin: 0; padding-left: 1.4em; }
.liste li { margin: 0.35em 0; }
.liste li::marker { color: var(--orange); font-family: var(--font-mono); }

.platzhalter { color: var(--muted); font-style: italic; }

/* --------------------------------------------------------------------------
   Steuerung unten: große Pfeile links und rechts
   -------------------------------------------------------------------------- */
.steuerung {
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  height: var(--steuer-h);
  z-index: 3;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 clamp(16px, 4vw, 56px);
}

.pfeil {
  width: 76px;
  height: 76px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  border: 1px solid var(--teal-line);
  background: var(--panel);
  color: var(--teal-hi);
  cursor: pointer;
  box-shadow: 0 0 0 rgba(25, 195, 209, 0);
  transition: color 0.2s, border-color 0.2s, box-shadow 0.2s, transform 0.15s, opacity 0.2s;
}

.pfeil svg {
  width: 40px;
  height: 40px;
  fill: none;
  stroke: currentColor;
  stroke-width: 2.4;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.pfeil:hover,
.pfeil:focus-visible {
  color: var(--orange-hi);
  border-color: rgba(255, 122, 26, 0.6);
  box-shadow: 0 0 24px rgba(255, 122, 26, 0.35);
  outline: none;
}

.pfeil:active { transform: scale(0.94); }

.pfeil:disabled {
  opacity: 0.25;
  cursor: default;
  color: var(--muted);
  border-color: var(--teal-line);
  box-shadow: none;
}

.zaehler {
  font-family: var(--font-mono);
  font-size: 0.8em;
  color: var(--muted);
  letter-spacing: 0.1em;
}

.zaehler #nr { color: var(--orange-hi); }

/* Dünner Fortschrittsbalken ganz unten */
.fortschritt {
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  height: 3px;
  z-index: 3;
  background: rgba(157, 243, 247, 0.08);
}

.fortschritt span {
  display: block;
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, var(--teal), var(--orange));
  transition: width 0.45s ease;
}

/* Handy: kleinere Pfeile */
@media (max-width: 600px) {
  :root { --steuer-h: 84px; }
  .pfeil { width: 58px; height: 58px; }
  .pfeil svg { width: 30px; height: 30px; }
}

@media (prefers-reduced-motion: reduce) {
  .folie, .folie.ist-aktiv, .fortschritt span, .pfeil { transition: none; }
  .folie, .folie.von-links { transform: none; }
}