/* VOLTHERM Firmenseite voltherm.de. Telefon zuerst, dann Desktop. Keine externen Schriften oder Skripte. */
:root {
  --navy: #0B1220; --navy2: #111a2e; --navy3: #18233b; --cyan: #19C3E6; --steel: #8FA3C8; --orange: #FF6B2C;
  --paper: #F7F8FA; --ink: #121722; --ink2: #4a5366; --line: #dfe4ec; --white: #fff;
  --font: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --r: 18px;
}
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 72px; -webkit-text-size-adjust: 100%; }
body { margin: 0; font: 17px/1.6 var(--font); background: var(--paper); color: var(--ink); overflow-x: hidden; }
img, svg { max-width: 100%; }
h1, h2, h3 { line-height: 1.15; margin: 0 0 .5em; letter-spacing: -.01em; }
h2 { font-size: clamp(28px, 6vw, 42px); }
h3 { font-size: 20px; }
p { margin: 0 0 1em; }
a { color: inherit; }
.wrap { width: 100%; max-width: 1140px; margin: 0 auto; padding: 0 20px; }
.sr { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); }
.skip { position: absolute; left: -999px; top: 8px; background: var(--cyan); color: var(--navy); padding: 8px 14px; border-radius: 8px; z-index: 100; }
.skip:focus { left: 8px; }
:focus-visible { outline: 3px solid var(--cyan); outline-offset: 3px; border-radius: 6px; }

/* ---------- Marke ---------- */
.brand { display: inline-flex; align-items: center; gap: 10px; text-decoration: none; color: var(--white); }
.brand svg { width: 34px; height: 34px; }
.wm { font-weight: 800; letter-spacing: .14em; font-size: 19px; }
.wm span { color: var(--cyan); }
.tagline { color: var(--steel); font-size: 11px; letter-spacing: .22em; margin: 8px 0 0; }

/* ---------- Kopfzeile ---------- */
.top { position: sticky; top: 0; z-index: 50; background: rgba(11,18,32,.86); backdrop-filter: saturate(140%) blur(12px); -webkit-backdrop-filter: saturate(140%) blur(12px); border-bottom: 1px solid rgba(143,163,200,.14); }
.top-row { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.nav { display: flex; gap: 26px; align-items: center; }
.nav a { color: #c9d3e6; text-decoration: none; font-size: 15px; font-weight: 600; }
.nav a:hover { color: var(--white); }
.menu-btn { display: none; }
@media (max-width: 760px) {
  .menu-btn { display: block; width: 44px; height: 44px; border: 0; background: none; position: relative; cursor: pointer; }
  .menu-btn span:first-child, .menu-btn span:first-child::before, .menu-btn span:first-child::after { position: absolute; left: 11px; width: 22px; height: 2px; background: var(--white); border-radius: 2px; transition: transform .25s, opacity .25s; }
  .menu-btn span:first-child { top: 21px; }
  .menu-btn span:first-child::before, .menu-btn span:first-child::after { content: ""; left: 0; }
  .menu-btn span:first-child::before { top: -7px; } .menu-btn span:first-child::after { top: 7px; }
  .menu-btn[aria-expanded="true"] span:first-child { background: transparent; }
  .menu-btn[aria-expanded="true"] span:first-child::before { transform: translateY(7px) rotate(45deg); }
  .menu-btn[aria-expanded="true"] span:first-child::after { transform: translateY(-7px) rotate(-45deg); }
  .nav { position: absolute; top: 64px; left: 0; right: 0; flex-direction: column; align-items: stretch; gap: 0; padding: 8px 20px 18px; background: var(--navy); border-bottom: 1px solid rgba(143,163,200,.18); display: none; }
  .nav.open { display: flex; }
  .nav a { padding: 13px 0; font-size: 17px; border-bottom: 1px solid rgba(143,163,200,.12); }
  .nav a.btn { margin-top: 14px; border: 0; justify-content: center; }
}

/* ---------- Knöpfe ---------- */
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 8px; min-height: 48px; padding: 12px 22px; border-radius: 999px; border: 0;
  background: var(--cyan); color: var(--navy) !important; font: 700 16px/1.2 var(--font); text-decoration: none; cursor: pointer;
  box-shadow: 0 8px 24px rgba(25,195,230,.28); transition: transform .15s, box-shadow .15s; }
.btn:hover { transform: translateY(-1px); box-shadow: 0 12px 30px rgba(25,195,230,.38); }
.btn-sm { min-height: 40px; padding: 8px 18px; font-size: 15px; }
.btn-ghost { background: rgba(255,255,255,.08); color: var(--white) !important; box-shadow: inset 0 0 0 1.5px rgba(143,163,200,.45); }
.btn-ghost:hover { box-shadow: inset 0 0 0 1.5px var(--cyan); }
.btn-line { background: transparent; color: var(--ink) !important; box-shadow: inset 0 0 0 1.5px var(--ink); }
.ic { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
.cta-row { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 26px; }

/* ---------- Hero ---------- */
.hero { position: relative; background: var(--navy); color: var(--white); overflow: hidden; padding: 56px 0 72px; }
.hero-glow { position: absolute; inset: -30%; pointer-events: none; background:
  radial-gradient(40% 35% at 72% 35%, rgba(25,195,230,.22), transparent 70%),
  radial-gradient(35% 30% at 20% 80%, rgba(143,163,200,.14), transparent 70%),
  radial-gradient(25% 20% at 85% 85%, rgba(255,107,44,.12), transparent 70%);
  animation: glow 18s ease-in-out infinite alternate; }
@keyframes glow { to { transform: translate3d(-4%, 3%, 0) rotate(8deg); } }
.hero-grid { position: relative; display: grid; gap: 40px; align-items: center; }
.eyebrow { color: var(--cyan); font-weight: 700; letter-spacing: .14em; text-transform: uppercase; font-size: 12px; margin-bottom: 18px; }
.hero h1 { font-size: clamp(34px, 8.4vw, 60px); margin-bottom: 20px; }
.grad { background: linear-gradient(90deg, var(--cyan), #7fe3f5 55%, #ffd2bf); -webkit-background-clip: text; background-clip: text; color: transparent; }
.grad-dark { background: linear-gradient(90deg, #0e9fc0, var(--cyan) 60%, var(--orange)); -webkit-background-clip: text; background-clip: text; color: transparent; }
.lead { color: #c5d0e6; font-size: 18px; max-width: 560px; }
.chips { list-style: none; display: flex; flex-wrap: wrap; gap: 8px; padding: 0; margin: 30px 0 0; }
.chips li { font-size: 13px; color: #c5d0e6; padding: 6px 12px; border-radius: 999px; border: 1px solid rgba(143,163,200,.3); }
.hero-art { display: flex; justify-content: center; }
.orbit { position: relative; width: min(84vw, 400px); aspect-ratio: 1; border-radius: 50%; border: 1px dashed rgba(143,163,200,.35); }
.orbit::before { content: ""; position: absolute; inset: 18%; border-radius: 50%; border: 1px solid rgba(25,195,230,.25); box-shadow: 0 0 80px rgba(25,195,230,.18) inset; }
.core { position: absolute; inset: 33%; display: grid; place-items: center; border-radius: 50%; background: radial-gradient(circle, #16233e, var(--navy)); box-shadow: 0 0 60px rgba(25,195,230,.35); }
.core svg { width: 62%; height: 62%; }
.node { --a: 0deg; position: absolute; left: 50%; top: 50%; width: 19%; aspect-ratio: 1; margin: -9.5%; display: grid; place-items: center;
  transform: rotate(var(--a)) translateY(-205%) rotate(calc(-1 * var(--a))); clip-path: polygon(50% 0, 100% 25%, 100% 75%, 50% 100%, 0 75%, 0 25%);
  background: linear-gradient(160deg, #1d3354, #10213a); animation: pulse 6s ease-in-out infinite; }
.node::after { content: ""; position: absolute; inset: 0; clip-path: inherit; box-shadow: inset 0 0 0 2px var(--cyan); }
.node svg { width: 48%; height: 48%; fill: none; stroke: var(--cyan); stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }
.node.warm svg { stroke: var(--orange); }
.n1 { --a: 0deg; } .n2 { --a: 60deg; animation-delay: -1s; } .n3 { --a: 120deg; animation-delay: -2s; }
.n4 { --a: 180deg; animation-delay: -3s; } .n5 { --a: 240deg; animation-delay: -4s; } .n6 { --a: 300deg; animation-delay: -5s; }
@keyframes pulse { 50% { filter: brightness(1.45); } }
@media (min-width: 900px) {
  .hero { padding: 90px 0 110px; }
  .hero-grid { grid-template-columns: 1.15fr .85fr; }
}

/* ---------- Abschnitte ---------- */
.sec { padding: 72px 0; }
.sec.soft { background: #eef2f7; }
.sec.dark { background: var(--navy); color: var(--white); }
.sec.dark p { color: #c5d0e6; }
.kicker { text-transform: uppercase; letter-spacing: .16em; font-size: 12px; font-weight: 800; color: #0e9fc0; margin-bottom: 10px; }
.dark .kicker { color: var(--cyan); }
.intro { color: var(--ink2); max-width: 640px; font-size: 18px; }
@media (min-width: 900px) { .sec { padding: 100px 0; } }

/* Leistungen */
.cards { display: grid; gap: 16px; margin-top: 34px; grid-template-columns: 1fr; }
@media (min-width: 620px) { .cards { grid-template-columns: 1fr 1fr; } }
@media (min-width: 980px) { .cards { grid-template-columns: repeat(3, 1fr); } }
.card { background: var(--white); border: 1px solid var(--line); border-radius: var(--r); padding: 26px 24px 20px; transition: transform .2s, box-shadow .2s; }
.card:hover { transform: translateY(-3px); box-shadow: 0 18px 40px rgba(11,18,32,.08); }
.card p { color: var(--ink2); margin: 0; font-size: 16px; }
.hexi { width: 56px; height: 56px; margin-bottom: 14px; }
.hexi use:first-child { fill: var(--navy); }
.hexi use:last-child { fill: none; stroke: var(--cyan); stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }
.card.warm .hexi use:last-child { stroke: var(--orange); }

/* Häkchenlisten */
.ticks { list-style: none; padding: 0; margin: 0 0 8px; }
.ticks li { position: relative; padding-left: 30px; margin-bottom: 10px; }
.ticks li::before { content: ""; position: absolute; left: 2px; top: .45em; width: 14px; height: 8px; border-left: 2.5px solid var(--cyan); border-bottom: 2.5px solid var(--cyan); transform: rotate(-45deg); }
.dark .ticks li { color: #dbe3f1; }

/* Klima */
.band-grid, .smart-grid, .contact-grid { display: grid; gap: 44px; align-items: center; }
@media (min-width: 900px) {
  .band-grid { grid-template-columns: 1.1fr .9fr; }
  .smart-grid { grid-template-columns: .8fr 1.2fr; }
  .contact-grid { grid-template-columns: .9fr 1.1fr; align-items: start; }
}
.band .btn { margin-top: 18px; }
.band-art { position: relative; height: 300px; border-radius: 24px; overflow: hidden;
  background: linear-gradient(180deg, #13223d, #0d1830); border: 1px solid rgba(143,163,200,.18); }
.sun { position: absolute; right: 26px; top: 22px; width: 64px; height: 64px; border-radius: 50%; background: radial-gradient(circle, #ffd27a, #ff9a3c 70%);
  box-shadow: 0 0 0 10px rgba(255,170,60,.12), 0 0 0 22px rgba(255,170,60,.06), 0 0 60px rgba(255,150,60,.5); }
.ac { position: absolute; left: 50%; top: 92px; width: 78%; transform: translateX(-50%); }
.ac-unit { position: relative; height: 66px; border-radius: 14px 14px 22px 22px; background: linear-gradient(180deg, #f6f8fb, #d9e0ea); box-shadow: 0 10px 30px rgba(0,0,0,.35); }
.ac-unit i { position: absolute; left: 10%; right: 10%; bottom: 12px; height: 6px; border-radius: 3px; background: #b6c2d3; }
.ac-unit::after { content: ""; position: absolute; right: 16px; top: 14px; width: 7px; height: 7px; border-radius: 50%; background: var(--cyan); box-shadow: 0 0 10px var(--cyan); }
.ac-air { position: relative; height: 120px; }
.ac-air span { position: absolute; top: 6px; width: 3px; height: 70px; border-radius: 3px; background: linear-gradient(180deg, rgba(25,195,230,.85), transparent); animation: air 2.4s ease-in infinite; }
.ac-air span:nth-child(1) { left: 28%; } .ac-air span:nth-child(2) { left: 50%; animation-delay: .8s; } .ac-air span:nth-child(3) { left: 72%; animation-delay: 1.6s; }
@keyframes air { from { transform: translateY(-10px); opacity: 0; } 30% { opacity: 1; } to { transform: translateY(60px); opacity: 0; } }

/* Smart Energy */
.phone { justify-self: center; width: min(72vw, 300px); border-radius: 34px; padding: 10px; background: var(--navy); box-shadow: 0 30px 60px rgba(11,18,32,.25), inset 0 0 0 2px #26324a; }
.phone img { display: block; width: 100%; height: auto; border-radius: 26px; }
.smart-grid p { color: var(--ink2); }

/* Ablauf */
.steps { list-style: none; counter-reset: s; padding: 0; margin: 34px 0 0; display: grid; gap: 14px; }
@media (min-width: 900px) { .steps { grid-template-columns: repeat(5, 1fr); } }
.steps li { counter-increment: s; position: relative; background: var(--white); border-radius: var(--r); padding: 56px 20px 20px; border: 1px solid var(--line); }
.steps li::before { content: counter(s); position: absolute; left: 20px; top: 16px; width: 30px; height: 30px; display: grid; place-items: center; border-radius: 50%;
  background: var(--navy); color: var(--cyan); font-weight: 800; font-size: 15px; }
.steps b { display: block; margin-bottom: 4px; }
.steps span { color: var(--ink2); font-size: 15px; }

/* Warum */
.why { display: grid; gap: 26px; margin-top: 30px; }
@media (min-width: 760px) { .why { grid-template-columns: 1fr 1fr; gap: 30px 50px; } }
.why div { border-left: 3px solid var(--cyan); padding-left: 18px; }
.why b { font-size: 19px; }
.why p { color: var(--ink2); margin: 6px 0 0; }

/* Kontakt */
.contact { list-style: none; padding: 0; margin: 26px 0 0; }
.contact li { display: flex; align-items: center; gap: 14px; padding: 12px 0; border-bottom: 1px solid rgba(143,163,200,.16); font-size: 18px; }
.contact svg { width: 22px; height: 22px; flex: none; fill: none; stroke: var(--cyan); stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
.contact a { text-decoration: none; }
.contact a:hover { color: var(--cyan); }
.anfrage { background: var(--navy2); border: 1px solid rgba(143,163,200,.2); border-radius: 22px; padding: 24px 20px; }
@media (min-width: 600px) { .anfrage { padding: 30px; } }
.anfrage fieldset { border: 0; padding: 0; margin: 0 0 16px; }
.anfrage legend { font-weight: 700; margin-bottom: 12px; }
.pick { display: flex; flex-wrap: wrap; gap: 8px; }
.pick input { position: absolute; opacity: 0; pointer-events: none; }
.pick span { display: inline-block; padding: 9px 14px; border-radius: 999px; border: 1.5px solid rgba(143,163,200,.4); font-size: 15px; cursor: pointer; user-select: none; transition: background .15s, border-color .15s; }
.pick input:checked + span { background: var(--cyan); border-color: var(--cyan); color: var(--navy); font-weight: 700; }
.pick input:focus-visible + span { outline: 3px solid var(--cyan); outline-offset: 2px; }
.fld { display: block; margin-bottom: 14px; }
.fld span { display: block; font-size: 14px; color: var(--steel); margin-bottom: 6px; }
.fld input, .fld textarea { width: 100%; font: 16px/1.4 var(--font); color: var(--white); background: var(--navy); border: 1.5px solid rgba(143,163,200,.3); border-radius: 12px; padding: 12px 14px; }
.fld input:focus, .fld textarea:focus { border-color: var(--cyan); outline: none; }
.fld input::placeholder, .fld textarea::placeholder { color: #66748f; }
.send { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 6px; }
.send .btn { flex: 1 1 200px; }
.fine { font-size: 13px; margin: 14px 0 0; color: var(--steel) !important; }
.err { color: #ffb59a !important; font-weight: 600; margin: 10px 0 0; }

/* Fußzeile */
.foot { background: #070c16; color: var(--steel); padding: 40px 0 26px; font-size: 15px; }
.foot-row { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 26px; }
.foot-nav { display: flex; flex-wrap: wrap; gap: 10px 22px; align-items: center; }
.foot-nav a { color: #c5d0e6; text-decoration: none; }
.foot-nav a:hover { color: var(--cyan); }
.copy { margin-top: 26px; font-size: 13px; color: #66748f; }

/* Einblenden beim Scrollen */
.js .reveal { opacity: 0; transform: translateY(18px); transition: opacity .7s, transform .7s cubic-bezier(.2,.8,.2,1); }
.js .reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; }
  .js .reveal { opacity: 1; transform: none; }
}

/* Smart Home: Loxone und Home Assistant nebeneinander */
.sys { display: grid; gap: 16px; margin: 34px 0 28px; }
@media (min-width: 760px) { .sys { grid-template-columns: 1fr 1fr; } }
.sys .card p { margin-bottom: 16px; }
.sys .ticks li { font-size: 16px; }
.badge { display: inline-block; vertical-align: middle; margin-left: 8px; padding: 3px 10px; border-radius: 999px; background: #e3f7fc; color: #0b7d97; font-size: 12px; font-weight: 700; letter-spacing: .04em; }