/* ==========================================================================
   Wirth Paletten – Stylesheet
   ========================================================================== */

@font-face {
  font-family: "Raleway";
  src: url("../fonts/raleway-latin.woff2") format("woff2");
  font-weight: 500 900;
  font-display: swap;
}
@font-face {
  font-family: "Source Sans 3";
  src: url("../fonts/source-sans-3-latin.woff2") format("woff2");
  font-weight: 200 900;
  font-display: swap;
}

:root {
  --blue: #054d9b;
  --blue-dark: #043c79;
  --text: #333;
  --heading: #383838;
  --link: #545454;
  --muted: #8d8d8d;
  --bg: #fff;
  --bg-alt: #eff2f6;
  --tab-inactive: #efefef;
  --line: #ebebeb;
  --footer-bg: #282828;
  --footer-text: #ababab;
  --notice: #e00000;

  --font-head: "Raleway", system-ui, sans-serif;
  --font-body: "Source Sans 3", "Source Sans Pro", system-ui, sans-serif;

  --container: 1240px;
  --gutter: 20px;
  --section-y: 60px;
}

/* --- Basis ---------------------------------------------------------------- */

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

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.7;
  color: var(--text);
  background: var(--bg);
}

img { max-width: 100%; height: auto; display: block; }

a { color: var(--link); text-decoration: none; transition: color .2s; }
a:hover { color: var(--blue); }

h1, h2, h3, h4 {
  font-family: var(--font-head);
  color: var(--heading);
  line-height: 1.2;
  margin: 0 0 20px;
}

p { margin: 0 0 20px; }

address { font-style: normal; }

:focus-visible { outline: 2px solid var(--blue); outline-offset: 3px; }

.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: 100;
  padding: 10px 16px;
  background: var(--blue);
  color: #fff;
}
.skip-link:focus { left: 0; }

.visually-hidden {
  position: absolute !important;
  width: 1px; height: 1px;
  overflow: hidden; clip: rect(0 0 0 0);
  white-space: nowrap;
}

/* --- Topbar & Header ------------------------------------------------------ */

.topbar {
  background: var(--blue);
  color: #fff;
  font-size: 13px;
  line-height: 1.7;
  padding: 5px 0;
}
.topbar__inner { text-align: right; }
.topbar a { color: #fff; }

.header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: #fff;
  transition: box-shadow .3s;
}
.header.is-scrolled { box-shadow: 0 2px 12px rgba(0, 0, 0, .08); }

.header__inner {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  min-height: 99px;
}

.header__logo { margin-bottom: 4px; }
.header__logo img { width: 200px; height: auto; }

.nav ul {
  display: flex;
  gap: 0 40px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav a {
  position: relative;
  display: block;
  font-family: var(--font-head);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .5px;
  text-transform: uppercase;
  color: #232323;
  transition: color .2s;
}
.nav a::after {
  content: "";
  position: absolute;
  left: 0; right: 0; bottom: -3px;
  height: 3px;
  background: var(--blue);
  transform: scaleX(0);
  transition: transform .25s;
}
.nav a:hover,
.nav a[aria-current="page"] { color: var(--blue); }
.nav a:hover::after,
.nav a[aria-current="page"]::after { transform: scaleX(1); }

.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  padding: 11px 9px;
  border: 0;
  background: none;
  cursor: pointer;
}
.nav-toggle span {
  display: block;
  height: 2px;
  margin: 5px 0;
  background: #232323;
  transition: transform .25s, opacity .25s;
}
.nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* --- Hero (Seitentitel mit Hintergrundbild) ------------------------------- */

.hero {
  position: relative;
  margin-top: 30px;
  padding: 220px 0 80px;
  background: #fff;
  overflow: hidden;
}
.hero__bg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: .4;
}
.hero .container { position: relative; }
.hero--small { padding: 0; height: 300px; }
.hero--flush { margin-top: 0; }
.hero__title {
  margin: 0;
  font-size: 48px;
  font-weight: 900;
  letter-spacing: 1px;
  text-transform: uppercase;
  color: var(--blue);
}

/* --- Sektionen ------------------------------------------------------------ */

.section { padding: var(--section-y) 0; }
.section--alt { background: var(--bg-alt); }
.section--spacious { padding: 90px 0 60px; }
.section--spacious-end { padding-bottom: 117px; }
.section--icons { padding: 120px 0 90px; }
.section--gase-intro { padding: 120px 0 90px; }
.feature--offset { padding-left: 40px; }
.feature--gas img, .feature--offset img { margin-bottom: 30px; }
.feature--gas h2, .feature--offset h2 { margin-bottom: 20px; }
.product-hero--gase { width: 600px; max-height: none; margin-bottom: 70px; }
.section--roomy-top { padding-top: calc(var(--section-y) * 2); }
.section--roomy-bottom { padding-bottom: calc(var(--section-y) * 2.5); }

.cert { width: 220px; margin-inline: auto; }
.indent { padding-left: 20px; }

.section-title {
  font-size: 41px;
  font-weight: 800;
  letter-spacing: 1px;
  text-transform: uppercase;
  color: var(--blue);
  margin-bottom: 10px;
}
.section-title--spaced { margin-bottom: 30px; }

.caption {
  display: block;
  margin-bottom: 11px;
  text-transform: uppercase;
  color: var(--blue);
}

.grid { display: grid; gap: 30px; }
.grid--2 { grid-template-columns: 585fr 565fr; column-gap: 50px; }
.grid--3 { grid-template-columns: repeat(3, 1fr); }
.grid--4 { grid-template-columns: repeat(4, 1fr); }
.grid--5 { grid-template-columns: repeat(5, 1fr); }
.grid--center { align-items: center; }
.grid--top { align-items: start; }

.btn {
  display: inline-block;
  padding: 15px 33px;
  background: var(--blue);
  color: #fff;
  font-family: var(--font-body);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .8px;
  text-transform: uppercase;
  line-height: 1.7;
  transition: background .2s;
}
.btn--block { margin: 10px 0 30px; }
.btn:hover { background: var(--blue-dark); color: #fff; text-decoration: none; }

.notice {
  color: var(--notice);
  font-weight: 700;
}

/* --- Slider (Startseite) -------------------------------------------------- */

.slider { position: relative; }
.slider__track {
  display: flex;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  scrollbar-width: none;
  list-style: none;
  margin: 0;
  padding: 0;
}
.slider__track::-webkit-scrollbar { display: none; }
.slider__track li { flex: 0 0 100%; scroll-snap-align: start; }
.slider__track img { width: 100%; aspect-ratio: 16 / 9; object-fit: cover; }

.slider__btn {
  position: absolute;
  top: 50%;
  width: 46px;
  height: 46px;
  margin-top: -23px;
  font-size: 22px;
  border: 0;
  background: rgba(0, 0, 0, .35);
  color: #fff;
  cursor: pointer;
  opacity: 0;
  transition: opacity .25s, background .2s;
}
.slider:hover .slider__btn,
.slider__btn:focus-visible { opacity: 1; }
.slider__btn:hover { background: rgba(0, 0, 0, .6); }
.slider__btn--prev { left: 35px; }
.slider__btn--next { right: 35px; }

/* --- Feature-Kacheln (Icon + Titel + Text) -------------------------------- */

.feature { text-align: center; }
.feature img { width: 100px; height: 100px; margin: 0 auto 10px; }
.feature--small img { margin-bottom: 30px; }
.feature h2,
.feature h3 {
  font-size: 28px;
  font-weight: 700;
  margin-bottom: 19px;
}

.feature--small h2,
.feature--small h3 { font-size: 22px; }

/* --- Bilder ---------------------------------------------------------------- */

.product-hero { margin: 0 auto 40px; max-height: 480px; width: auto; }
.icon-lg { width: 100px; height: 100px; margin-inline: auto; }
.wide-image { width: 100%; margin-top: 40px; }

.tabs__panel h2.h3 { font-size: 36px; font-weight: 700; }

/* --- Angebots-Kacheln ----------------------------------------------------- */

.offer { text-align: center; }
.offer img { margin: 0 auto 10px; transition: transform .3s; }
.offer a:hover img { transform: translateY(-4px); }
.offer h3 {
  margin: 0;
  font-size: 15px;
  font-weight: 800;
  letter-spacing: 1px;
  text-transform: uppercase;
}
.offer h3 a { color: var(--heading); }
.offer h3 a:hover { color: var(--blue); }

/* --- Tabs ------------------------------------------------------------------ */

.tabs__list {
  display: flex;
  flex-wrap: wrap;
  gap: 2px;
}
.tabs__tab {
  padding: 18px 28px 15px;
  border: 0;
  background: var(--tab-inactive);
  color: var(--muted);
  font-family: var(--font-head);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 1.5px;
  line-height: 1.7;
  text-transform: uppercase;
  cursor: pointer;
  transition: color .2s, background .2s;
}
.tabs__tab:hover { color: #464646; }
.tabs__tab[aria-selected="true"] { background: #fff; color: #464646; }

.tabs__panel {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 30px;
  align-items: start;
  padding: 45px 15px 5px;
  background: #fff;
}
.tabs__panel > img { margin-bottom: 29px; }
.tabs__panel > img.flush { margin-bottom: 20px; }
.section:not(.section--alt) .tabs__panel,
.section:not(.section--alt) .tabs__tab[aria-selected="true"] { border: 1px solid var(--line); }
.section:not(.section--alt) .tabs__tab[aria-selected="true"] { border-bottom-color: #fff; margin-bottom: -1px; }

.tabs__panel[hidden] { display: none; }
.tabs__panel h3 { font-size: 36px; font-weight: 700; }

/* Ohne JavaScript: alle Panels untereinander */
.tabs:not(.is-ready) .tabs__list { display: none; }
.tabs:not(.is-ready) .tabs__panel + .tabs__panel { margin-top: 20px; }

/* --- Akkordeon (native <details>) ------------------------------------------ */

.accordion { margin: 30px 0 40px; }
.cta { margin: 0; }
.accordion details {
  margin-bottom: 10px;
  background: #fff;
  border-radius: 3px;
}
.section:not(.section--alt) .accordion details { background: #f3f3f3; }

.accordion summary {
  display: flex;
  align-items: center;
  gap: 18px;
  padding: 23px 25px 22px;
  font-family: var(--font-head);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 1px;
  line-height: 16px;
  text-transform: uppercase;
  color: #191919;
  cursor: pointer;
  list-style: none;
}
.accordion summary::-webkit-details-marker { display: none; }
.accordion summary::before {
  content: "+";
  flex: 0 0 auto;
  width: 14px;
  font-size: 18px;
  line-height: 16px;
  color: var(--blue);
  transition: transform .25s;
}
.accordion details[open] summary::before { content: "–"; }
.accordion__body { padding: 0 25px 10px 57px; }
.accordion__body ul { margin: 0 0 20px; padding-left: 18px; }

/* --- Listen mit Icons (Schmierstoffe) -------------------------------------- */

.icon-list { list-style: none; margin: 0; padding: 0; }
.icon-list li {
  display: flex;
  align-items: center;
  gap: 20px;
  padding: 18px 0;
  border-bottom: 1px solid var(--line);
  text-align: right;
}
.icon-list li:last-child { border-bottom: 0; }
.icon-list img { width: 64px; height: 64px; flex: 0 0 64px; }
.icon-list span { flex: 1; }

/* --- Partner-Logos --------------------------------------------------------- */

.partner { text-align: center; }
.partner img {
  height: 90px;
  width: auto;
  max-width: 100%;
  margin: 0 auto 15px;
  object-fit: contain;
}
.partner a { font-size: 14px; }

/* --- Rechtstexte ----------------------------------------------------------- */

.legal { max-width: 900px; }
.legal h1 {
  font-size: 41px;
  font-weight: 900;
  letter-spacing: 1px;
  text-transform: uppercase;
}
.legal h2 { font-size: 24px; margin-top: 40px; }
.legal h3 { font-size: 18px; margin-top: 25px; margin-bottom: 10px; }

/* --- Footer ---------------------------------------------------------------- */

.footer {
  padding: 70px 0 60px;
  background: var(--footer-bg);
  color: var(--footer-text);
  font-size: 15px;
}
.footer__inner {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 50px;
  padding-inline: 30px;
}
.footer__col { margin-bottom: 20px; }
.footer a { color: #bababa; }
.footer a:hover { color: #fff; }

.to-top {
  position: fixed;
  right: 30px;
  bottom: 30px;
  z-index: 40;
  display: grid;
  place-items: center;
  width: 45px;
  height: 45px;
  border-radius: 50%;
  background: #dbdbdb;
  color: #313131;
  opacity: 0;
  pointer-events: none;
  transition: opacity .3s, background .2s;
}
.to-top.is-visible { opacity: 1; pointer-events: auto; }
.to-top:hover { background: #c8c8c8; color: #313131; }

/* --- Responsive ------------------------------------------------------------ */

@media (max-width: 1100px) {
  .nav ul { gap: 0 20px; }
  .grid--5 { grid-template-columns: repeat(3, 1fr); }
}

@media (max-width: 999px) {
  :root { --section-y: 50px; }

  .header__inner { min-height: 80px; }
  .header__logo img { width: 150px; }

  .nav-toggle { display: block; }
  .nav {
    position: fixed;
    top: 0; right: 0; bottom: 0;
    width: min(320px, 85vw);
    padding: 90px 30px 30px;
    background: #fff;
    box-shadow: -4px 0 24px rgba(0, 0, 0, .12);
    transform: translateX(100%);
    visibility: hidden;
    transition: transform .3s, visibility 0s .3s;
  }
  .nav.is-open { transform: none; visibility: visible; transition: transform .3s; }
  .nav ul { flex-direction: column; }
  .nav a { padding: 14px 0; border-bottom: 1px solid var(--line); font-size: 14px; }
  .nav a::after { display: none; }
  .nav-toggle { position: relative; z-index: 60; }

  .topbar { display: none; }

  .hero { padding: 140px 0 40px; }
  .section--icons { padding: 60px 0 40px; }
  .section--spacious { padding: 60px 0 40px; }
  .section--spacious-end { padding-bottom: 60px; }
  .hero__title { font-size: 34px; }
  .section-title { font-size: 32px; }

  .grid--2,
  .grid--3,
  .tabs__panel,
  .footer__inner { grid-template-columns: 1fr; }
  .grid--4 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 600px) {
  :root { --gutter: 16px; }
  .hero { padding: 110px 0 30px; }
  .hero__title { font-size: 26px; }
  .section-title,
  .legal h1 { font-size: 26px; }
  .tabs__panel h3,
  .tabs__panel h2.h3 { font-size: 26px; }
  .feature h2,
  .feature h3 { font-size: 22px; }
  .hero--small { height: 160px; }
  .grid--5 { grid-template-columns: repeat(2, 1fr); }
  .tabs__tab { flex: 1 1 auto; padding: 14px 16px 12px; }
  .accordion__body { padding-left: 25px; }
  .icon-list li { text-align: left; }
  .to-top { right: 16px; bottom: 16px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; }
}