:root{
  /* ---- brand colours ---- */
  --navy:        #101728;
  --green:       #88AB27;
  --white:       #FFFFFF;
  --ink:         #0F1819;

  /* ---- button gradient (cyan -> green) ---- */
  --grad-a:      #068CBE;
  --grad-b:      #84AA2C;

  /* ---- decorative glows ---- */
  --glow-cyan:   #0086BF;
  --glow-blue:   #1F41BB;
  --glow-purple: #251170;

  /* ---- typography ---- */
  --font-sans: Arial, "Helvetica Neue", Helvetica, "Liberation Sans", sans-serif;

  --fs-h1: clamp(2.25rem, 1.30rem + 3.6vw, 3.75rem);
  --fs-h2: clamp(1.85rem, 1.20rem + 2.5vw, 2.9rem);
  --fs-lead: clamp(1rem, 0.95rem + 0.25vw, 1.20rem);

  /* ---- layout ---- */
  /* wider content area on large screens (Melina's note) */
  --container: min(1600px, 92vw);
  --gutter: clamp(1.25rem, 0.5rem + 3vw, 4.6875rem);
  --section-y: clamp(4rem, 2rem + 8vw, 9rem);
  --radius-img: 24px;
  --nav-h: 88px;

  --ease: cubic-bezier(.22,.61,.36,1);
}

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

html{ scroll-behavior:smooth; scroll-padding-top:var(--nav-h); }

body{
  margin:0;
  font-family:var(--font-sans);
  font-size:var(--fs-lead);
  line-height:1.6;
  color:var(--white);
  background:var(--navy);
  -webkit-font-smoothing:antialiased;
  overflow-x:hidden;
}

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

.skip-link{
  position:absolute; left:-9999px; top:0; z-index:200;
  background:var(--white); color:var(--ink);
  padding:.75rem 1.25rem; border-radius:0 0 8px 0; font-weight:700;
}
.skip-link:focus{ left:0; }

:focus-visible{ outline:3px solid var(--grad-a); outline-offset:3px; border-radius:4px; }

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

.section{ padding-block:var(--section-y); position:relative; overflow:hidden; }
.section--dark { background:var(--navy);  color:var(--white); }
.section--green{ background:var(--green); color:var(--ink);  }
.section--light{ background:var(--white); color:var(--ink);  }

.grid{ display:grid; gap:clamp(2.5rem,1rem + 6vw,6rem); align-items:center; }
.grid--split{ grid-template-columns:1fr 1fr; }

/* ==========================  typography  ========================== */
.h1{
  font-size:var(--fs-h1);
  line-height:1.1;
  font-weight:700;
  letter-spacing:-.02em;
  margin:0 0 clamp(2rem,1rem + 4vw,3.75rem);
}
.h2{
  font-size:var(--fs-h2);
  line-height:1.16;
  font-weight:700;
  letter-spacing:-.02em;
  margin:0 0 1.75rem;
}
.lead{ margin:0 0 2.5rem; max-width:36em; }
.section--dark .lead{ color:rgba(255,255,255,.92); }

/* ==========================  buttons  ========================== */
.btn{
  display:inline-flex; align-items:center; justify-content:center;
  min-height:66px;
  padding:.9rem 2.5rem;
  border:0; border-radius:999px;
  font:inherit; font-weight:700; font-size:1.05rem;
  color:var(--ink);
  text-decoration:none; cursor:pointer;
  transition:transform .25s var(--ease), box-shadow .25s var(--ease),
             background-position .6s var(--ease), color .25s var(--ease);
}

/* gradient pill – the gradient drifts on hover */
.btn--gradient{
  background-image:linear-gradient(90deg,
      var(--grad-a) 0%, var(--grad-b) 50%, var(--grad-a) 100%);
  background-size:200% 100%;
  background-position:0% 50%;
}
.btn--gradient:hover,
.btn--gradient:focus-visible{
  background-position:100% 50%;
  transform:translateY(-2px);
  box-shadow:0 12px 30px -10px rgba(6,140,190,.65);
}
.btn--gradient:active{
  background-image:none; background-color:var(--white); color:#000;
  transform:translateY(0);
}

.btn--dark{ background:var(--navy); color:var(--white); }
.btn--dark:hover,
.btn--dark:focus-visible{ transform:translateY(-2px); box-shadow:0 12px 30px -12px rgba(0,0,0,.55); }
.btn--dark:active{ background:var(--white); color:#000; transform:translateY(0); }

/* ==========================  navigation  ========================== */
.nav{
  position:fixed; inset:0 0 auto 0; z-index:100;
  background:transparent;
  transition:background-color .3s var(--ease), box-shadow .3s var(--ease);
}
.nav__inner{
  display:flex; align-items:center; gap:clamp(1rem,.2rem + 1.6vw,2rem);
  min-height:var(--nav-h);
}

/* two logo files: white wordmark on dark, dark wordmark on white */
.nav__logo{ flex:0 0 auto; display:flex; align-items:center; position:relative; }
.nav__logo picture{ display:block; }
.nav__logo img{
  height:clamp(38px,1.9rem + 1.3vw,52px);
  width:auto;
  transition:opacity .3s var(--ease);
}
.nav__logo picture:last-child{ position:absolute; inset:0; display:flex; align-items:center; }
.nav__logo-dark{ opacity:0; }
.nav.is-scrolled .nav__logo-light,
.nav.is-menu-open .nav__logo-light{ opacity:0; }
.nav.is-scrolled .nav__logo-dark,
.nav.is-menu-open .nav__logo-dark{ opacity:1; }

.nav__menu{
  display:flex; align-items:center;
  gap:clamp(1rem,-.4rem + 2.6vw,3.25rem);
  margin-left:auto; min-width:0;
}
.nav__menu > a{
  text-decoration:none;
  font-size:clamp(.95rem,.85rem + .25vw,1.05rem);
  color:var(--white);
  padding:.4rem 0; position:relative; white-space:nowrap;
  transition:color .3s var(--ease);
}
.nav__menu > a::after{
  content:""; position:absolute; left:0; right:100%; bottom:0; height:2px;
  background:currentColor; transition:right .3s var(--ease);
}
.nav__menu > a:hover::after,
.nav__menu > a:focus-visible::after{ right:0; }

/* white bar + dark text once scrolled */
.nav.is-scrolled{ background:var(--white); box-shadow:0 2px 18px rgba(0,0,0,.10); }
.nav.is-scrolled .nav__menu > a,
.nav.is-scrolled .lang__btn{ color:var(--ink); }
.nav.is-scrolled .nav__burger span{ background:var(--ink); }

/* language dropdown */
.lang{ position:relative; }
.lang__btn{
  display:inline-flex; align-items:center; gap:.5rem;
  background:none; border:0; cursor:pointer;
  font:inherit; font-size:1.05rem; color:var(--white);
  padding:.4rem 0; transition:color .3s var(--ease);
}
.lang__btn svg{ width:10px; height:6px; transition:transform .3s var(--ease); }
.lang.is-open .lang__btn svg{ transform:rotate(180deg); }

.lang__list{
  position:absolute; right:0; top:calc(100% + .6rem);
  margin:0; padding:.4rem; list-style:none;
  min-width:210px;
  background:var(--white); color:var(--ink);
  border-radius:12px; box-shadow:0 16px 40px -12px rgba(0,0,0,.35);
  opacity:0; visibility:hidden; transform:translateY(-6px);
  transition:opacity .25s var(--ease), transform .25s var(--ease), visibility .25s;
}
.lang.is-open .lang__list{ opacity:1; visibility:visible; transform:translateY(0); }
.lang__list button{
  width:100%; text-align:left; background:none; border:0; cursor:pointer;
  font:inherit; font-size:1rem; color:var(--ink);
  padding:.7rem .9rem; border-radius:8px;
}
.lang__list button:hover,
.lang__list button:focus-visible{ background:rgba(0,0,0,.06); }
.lang__list button[aria-current="true"]{ font-weight:700; color:var(--grad-a); }

/* burger */
.nav__burger{
  display:none; margin-left:auto;
  width:46px; height:46px; padding:10px;
  background:none; border:0; cursor:pointer;
}
.nav__burger span{
  display:block; height:2px; margin:5px 0; border-radius:2px;
  background:var(--white);
  transition:transform .3s var(--ease), opacity .2s var(--ease), background-color .3s var(--ease);
}
.nav__burger[aria-expanded="true"] span:nth-child(1){ transform:translateY(7px) rotate(45deg); }
.nav__burger[aria-expanded="true"] span:nth-child(2){ opacity:0; }
.nav__burger[aria-expanded="true"] span:nth-child(3){ transform:translateY(-7px) rotate(-45deg); }

/* ==========================  hero  ========================== */
.hero{ padding-top:calc(var(--nav-h) + var(--section-y)); }
.hero__text .btn{ margin-top:.5rem; }

/* ============  decorative: technical "floor plan" motif  ============ */
/* Very low-contrast grid + tank circles, echoing a plant layout drawing. */
.has-blueprint::before{
  content:"";
  position:absolute; inset:0; z-index:0; pointer-events:none;
  background-image:
    radial-gradient(circle at 12% 78%, transparent 54px, rgba(255,255,255,.055) 55px, transparent 57px),
    radial-gradient(circle at 12% 78%, transparent 84px, rgba(255,255,255,.045) 85px, transparent 87px),
    radial-gradient(circle at 27% 26%, transparent 38px, rgba(255,255,255,.05) 39px, transparent 41px),
    linear-gradient(rgba(255,255,255,.028) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,.028) 1px, transparent 1px);
  background-size:auto, auto, auto, 88px 88px, 88px 88px;
  mask-image:linear-gradient(180deg, transparent, #000 22%, #000 78%, transparent);
  -webkit-mask-image:linear-gradient(180deg, transparent, #000 22%, #000 78%, transparent);
}
.has-blueprint > .container{ position:relative; z-index:1; }

/* ============  decorative: glow that follows the pointer  ============ */
.cursor-glow{
  position:fixed; top:0; left:0; z-index:0;
  width:520px; height:520px; margin:-260px 0 0 -260px;
  border-radius:50%;
  pointer-events:none; opacity:0;
  background:radial-gradient(circle closest-side,
             rgba(6,140,190,.20) 0%, rgba(6,140,190,.10) 45%, rgba(6,140,190,0) 72%);
  transition:opacity .5s var(--ease);
  will-change:transform;
}
body.pointer-fine .cursor-glow{ opacity:1; }

/* ==========================  media + CSS glow  ========================== */
.media{ margin:0; position:relative; }

.media img,
.media video{
  position:relative; z-index:1;
  width:100%; border-radius:var(--radius-img);
  object-fit:cover;
  transition:transform .55s var(--ease), box-shadow .55s var(--ease);
}

.media--glow::before{
  content:"";
  position:absolute; z-index:0; inset:-16%;
  background:radial-gradient(closest-side circle at 50% 50%,
              var(--glow-cyan) 0%,
              rgba(0,134,191,.55) 45%,
              rgba(0,134,191,.16) 68%,
              rgba(0,134,191,0) 78%);
  filter:blur(18px);
  opacity:.95;
  transition:opacity .55s var(--ease), transform .55s var(--ease);
  pointer-events:none;
}

.media:hover img{ transform:scale(1.03); }
.media--glow:hover::before{ opacity:1; transform:scale(1.06); }

/* gentle 3-D tilt that follows the pointer (set by main.js) */
.media--tilt{ perspective:1100px; }
.media--tilt picture,
.media--tilt img{
  transform-style:preserve-3d;
  transform:rotateX(var(--ry,0deg)) rotateY(var(--rx,0deg));
  transition:transform .35s var(--ease);
}

.media--portrait img{ max-width:405px; }
.media--icon img{ width:min(260px,58%); margin-inline:auto; border-radius:0; }
.media--icon:hover img{ transform:scale(1.04) rotate(-1deg); }

/* section-level blue/purple glow (podcast + footer) */
.glow-blue::after{
  content:""; position:absolute; z-index:0; pointer-events:none;
  right:-10%; bottom:-45%;
  width:min(940px,85vw); aspect-ratio:1;
  background:
    radial-gradient(closest-side circle at 60% 55%, rgba(31,65,187,.85) 0%, rgba(31,65,187,.32) 52%, rgba(31,65,187,0) 72%),
    radial-gradient(closest-side circle at 32% 38%, rgba(37,17,110,.85) 0%, rgba(37,17,110,.30) 55%, rgba(37,17,110,0) 75%);
  filter:blur(26px);
}
.glow-blue > .container{ position:relative; z-index:1; }

/* ==========================  checklist  ========================== */
.checklist{ list-style:none; margin:0; padding:0; display:grid; gap:clamp(1.35rem,.6rem + 2vw,2.4rem); }
.checklist li{ display:flex; align-items:center; gap:1.15rem; font-weight:700; line-height:1.35; }
.checklist img{ width:48px; height:48px; flex:none; }

/* ==========================  platform buttons  ========================== */
.platforms{ display:grid; gap:1.5rem; justify-items:start; }
.platforms .btn{ min-width:236px; }

/* ==========================  footer  ========================== */
.footer{ padding-block:clamp(3.5rem,2rem + 6vw,7rem); }
.footer .grid--split{ align-items:start; }
.footer p{ margin:0 0 1.4rem; line-height:1.55; }
.footer a{ text-decoration:underline; text-underline-offset:3px; }
.footer__logo{ width:auto; height:132px; margin-bottom:2rem; }
.footer__logo--sm{ height:64px; }

/* ==========================  scroll reveals  ========================== */
.reveal{
  opacity:0; transform:translateY(28px);
  transition:opacity .7s var(--ease), transform .7s var(--ease);
}
.reveal--right{ transform:translateY(28px) translateX(24px); }
.reveal.is-visible{ opacity:1; transform:none; }

.checklist li.reveal:nth-child(2){ transition-delay:.08s; }
.checklist li.reveal:nth-child(3){ transition-delay:.16s; }
.checklist li.reveal:nth-child(4){ transition-delay:.24s; }
.platforms .btn:nth-child(2){ transition-delay:.08s; }
.platforms .btn:nth-child(3){ transition-delay:.16s; }

/* ==========================  responsive  ========================== */
@media (max-width:1100px){
  :root{ --nav-h:80px; }

  .nav__burger{ display:block; }

  /* Melina: logo should be BIGGER on mobile */
  .nav__logo img{ height:clamp(38px,4.6vw + 26px,48px); }

  .nav.is-menu-open .nav__burger span{ background:var(--white); }

  /* ---- off-canvas drawer, slides in from the right ---- */
  .nav__menu{
    position:fixed;
    top:0; right:0; bottom:0; left:auto;
    width:min(400px,88vw);
    height:100vh;            /* fallback first */
    height:100svh;           /* modern units where supported */
    display:-webkit-box; display:-webkit-flex; display:flex;
    -webkit-flex-direction:column; flex-direction:column;
    align-items:stretch; justify-content:flex-start;
    gap:0; margin-left:0;
    background:var(--navy); color:var(--white);
    padding:0 0 2rem;
    box-shadow:-24px 0 60px -30px rgba(0,0,0,.75);
    -webkit-transform:translateX(100%);
            transform:translateX(100%);
    visibility:hidden;
    -webkit-transition:-webkit-transform .38s var(--ease), visibility .38s;
            transition:transform .38s var(--ease), visibility .38s;
    overflow-y:auto;
    -webkit-overflow-scrolling:touch;
    overscroll-behavior:contain;
  }
  .nav__menu.is-open{
    -webkit-transform:translateX(0);
            transform:translateX(0);
    visibility:visible;
  }


  .nav__menu > a{
    color:var(--white);
    padding:1.05rem var(--drawer-pad);
    border-bottom:1px solid rgba(255,255,255,.10);
    font-size:1.08rem;
  }
  .nav__menu > a::after{ display:none; }
  .nav__menu > a:hover,
  .nav__menu > a:focus-visible{ background:rgba(255,255,255,.06); }

  /* language switcher: last item, pinned to the bottom of the panel */
  .lang{
    margin-top:auto;                 /* pushes it down when links are short */
    position:-webkit-sticky; position:sticky; bottom:0; z-index:2;
    background:var(--navy);
    border-top:1px solid rgba(255,255,255,.16);
    padding:.9rem var(--drawer-pad) 1.15rem;
  }
  .lang__btn{
    color:var(--white); width:100%; justify-content:flex-start;
    padding:.7rem 0; font-size:1.08rem;
  }
  .lang__btn .lang__chev{ margin-left:auto; }
  .lang__list{
    position:static; opacity:1; visibility:visible; transform:none;
    background:transparent; box-shadow:none; min-width:0;
    padding:0; margin-top:.35rem; display:none;
  }
  .lang.is-open .lang__list{ display:block; }
  .lang__list button{
    color:var(--white); padding:.8rem .75rem; border-radius:12px;
  }
  .lang__list button:hover,
  .lang__list button:focus-visible{ background:rgba(255,255,255,.09); }
  .lang__list button[aria-current="true"]{ color:var(--white); background:rgba(6,140,190,.22); }

  .nav.is-scrolled .lang__btn{ color:var(--ink); }
  .nav.is-menu-open .lang__btn,
  .nav.is-menu-open .nav__menu > a{ color:var(--white); }

  body.has-menu-open{ overflow:hidden; }

  .grid--split{ grid-template-columns:1fr; }
  .hero__grid .media,
  #game .media{ order:-1; }

  .media--portrait img{ max-width:340px; margin-inline:auto; }

  /* Melina: clipboard icon smaller on mobile */
  .media--icon img{ width:min(150px,38%); }

  .platforms{ justify-items:stretch; }
  .platforms .btn{ width:100%; }

  .cursor-glow{ display:none; }
  .media--tilt picture,
  .media--tilt img{ transform:none !important; }
}

@media (max-width:560px){
  .btn{ width:100%; min-height:60px; padding-inline:1.5rem; }
  .checklist img{ width:40px; height:40px; }
  .footer__logo{ height:104px; }
  .footer__logo--sm{ height:56px; }
  .media--glow::before{ inset:-10%; filter:blur(14px); }
  .media--icon img{ width:min(124px,34%); }
  .has-blueprint::before{ background-size:auto,auto,auto,58px 58px,58px 58px; }
}


/* ==========================================================================
   QUESTIONNAIRE PAGE (fragebogen.html)
   Reuses the same tokens, buttons and reveal system as the home page.
   ========================================================================== */

.container--narrow{ max-width:min(860px,92vw); }

.page-head{ padding-top:calc(var(--nav-h) + var(--section-y)); }
.eyebrow{
  margin:0 0 1rem; font-weight:700; letter-spacing:.14em; text-transform:uppercase;
  font-size:.85rem; color:var(--grad-b);
}
.h1--tight{ margin-bottom:1.5rem; }
.page-head .lead{ margin-bottom:0; }

/* ---- form shell ---- */
.form{ display:grid; gap:clamp(2rem,1rem + 3vw,3.25rem); }
.form__group{ border:0; margin:0; padding:0; display:grid; gap:1rem; }
.form__legend{
  font-size:clamp(1.15rem,1rem + .5vw,1.4rem); font-weight:700;
  color:var(--ink); padding:0; margin:0;
}
.form__hint{ margin:-.4rem 0 0; font-size:.95rem; color:rgba(15,24,25,.62); }

/* ---- text fields ---- */
.field{
  width:100%; font:inherit; color:var(--ink);
  background:#fff;
  border:2px solid rgba(15,24,25,.18);
  border-radius:14px; padding:1rem 1.15rem;
  transition:border-color .25s var(--ease), box-shadow .25s var(--ease);
}
.field::placeholder{ color:rgba(15,24,25,.42); }
.field:hover{ border-color:rgba(15,24,25,.34); }
.field:focus{
  outline:0; border-color:var(--grad-a);
  box-shadow:0 0 0 4px rgba(6,140,190,.16);
}
textarea.field{ resize:vertical; min-height:150px; }

/* ---- radio / checkbox cards ---- */
.choice-grid{ display:grid; grid-template-columns:repeat(auto-fit,minmax(220px,1fr)); gap:.85rem; }
.choice{
  display:flex; align-items:center; gap:.85rem;
  padding:1rem 1.15rem; cursor:pointer;
  border:2px solid rgba(15,24,25,.18); border-radius:14px;
  background:#fff; line-height:1.35;
  transition:border-color .2s var(--ease), background-color .2s var(--ease), transform .2s var(--ease);
}
.choice--wide{ align-items:flex-start; }
.choice:hover{ border-color:rgba(15,24,25,.38); transform:translateY(-1px); }
.choice input{
  appearance:none; -webkit-appearance:none;
  width:22px; height:22px; flex:none; margin:0;
  border:2px solid rgba(15,24,25,.38); background:#fff;
  cursor:pointer; position:relative;
  transition:border-color .2s var(--ease), background-color .2s var(--ease);
}
.choice input[type=radio]{ border-radius:50%; }
.choice input[type=checkbox]{ border-radius:6px; }
.choice input:checked{ border-color:var(--grad-a); background:var(--grad-a); }
.choice input[type=radio]:checked::after{
  content:""; position:absolute; inset:4px; border-radius:50%; background:#fff;
}
.choice input[type=checkbox]:checked::after{
  content:""; position:absolute; left:6px; top:2px;
  width:6px; height:11px; border:solid #fff; border-width:0 2.5px 2.5px 0;
  transform:rotate(45deg);
}
.choice:has(input:checked){ border-color:var(--grad-a); background:rgba(6,140,190,.06); }
.choice input:focus-visible{ outline:3px solid var(--grad-a); outline-offset:3px; }

/* ---- 1–5 rating scale ---- */
.rate{ display:grid; gap:.7rem; }
.rate + .rate{ margin-top:.5rem; }
.rate__label{ font-weight:700; }
.rate__scale{ display:flex; gap:.6rem; flex-wrap:wrap; }
.rate__scale label{ cursor:pointer; }
.rate__scale input{ position:absolute; opacity:0; width:0; height:0; }
.rate__scale span{
  display:grid; place-items:center;
  width:58px; height:58px; border-radius:50%;
  border:2px solid rgba(15,24,25,.18); background:#fff;
  font-weight:700; font-size:1.05rem;
  transition:border-color .2s var(--ease), background-color .2s var(--ease),
             color .2s var(--ease), transform .2s var(--ease);
}
.rate__scale label:hover span{ border-color:rgba(15,24,25,.4); transform:translateY(-2px); }
.rate__scale input:checked + span{
  border-color:transparent; color:var(--ink); transform:translateY(-2px);
  background-image:linear-gradient(90deg,var(--grad-a),var(--grad-b));
}
.rate__scale input:focus-visible + span{ outline:3px solid var(--grad-a); outline-offset:3px; }
.rate__legend{ margin-top:.2rem; }

/* ---- validation ---- */
.form__error{
  margin:0; font-size:.95rem; font-weight:700; color:#B3261E;
  display:none;
}
.form__error.is-shown{ display:block; }
.form__group.has-error .field,
.form__group.has-error .choice{ border-color:#B3261E; }

/* ---- actions + status ---- */
.form__actions{ display:flex; align-items:center; gap:1.5rem; flex-wrap:wrap; }
.form__back{ font-weight:700; text-decoration:underline; text-underline-offset:3px; color:var(--ink); }
.form__status{ margin:0; font-weight:700; min-height:1.5em; }
.form__status.is-error{ color:#B3261E; }

/* ---- thank-you panel ---- */
.thanks[hidden]{ display:none !important; }
.thanks{ text-align:center; display:grid; justify-items:center; gap:1rem; padding-block:2rem; }
.thanks img{ width:72px; height:72px; }
.thanks .lead{ margin-bottom:1.5rem; }

@media (max-width:560px){
  .choice-grid{ grid-template-columns:1fr; }
  .rate__scale span{ width:50px; height:50px; font-size:1rem; }
  .form__actions{ flex-direction:column; align-items:stretch; }
  .form__back{ text-align:center; }
}


/* ==========================================================================
   1. SCROLL PROGRESS – "the water gets cleaner as you go down"
   The bar's gradient is anchored to the viewport width, so the leading edge
   moves from murky brown through grey-green into clear cyan while scrolling.
   ========================================================================== */
.progress{
  position:fixed; inset:0 0 auto 0; z-index:110;
  height:4px; background:rgba(255,255,255,.10);
  pointer-events:none;
}
.progress__fill{
  display:block; height:100%; width:0;
  background-image:linear-gradient(90deg,
      #6B4A2F 0%,      /* raw / murky      */
      #7C6B45 22%,     /* grit removed     */
      #55705F 44%,     /* primary settled  */
      #2E7E93 66%,     /* biology working  */
      #0F9BC9 84%,     /* clarified        */
      #35C4E8 100%);   /* clean effluent   */
  background-size:100vw 100%;
  background-repeat:no-repeat;
  transition:width .12s linear;
}

/* ==========================================================================
   2. LIQUID SECTION DIVIDERS
   Each section ends in a wave filled with the NEXT section's colour, so the
   bands flow into each other instead of meeting in a hard line.
   ========================================================================== */
.wave{
  position:absolute; left:0; bottom:-1px; z-index:2;
  width:100%; line-height:0; pointer-events:none;
}
.wave svg{
  display:block;
  width:calc(100% + 140px);
  height:clamp(46px,5.5vw,92px);
  margin-left:-70px;
}
.wave path{ transition:fill .3s var(--ease); }

/* back layer drifts one way, front layer the other – very slow, tiny amplitude */
.wave__back { opacity:.45; animation:waveDriftA 19s ease-in-out infinite alternate; }
.wave__front{ animation:waveDriftB 15s ease-in-out infinite alternate; }
@keyframes waveDriftA{ from{ transform:translate3d(0,0,0);    } to{ transform:translate3d(46px,4px,0); } }
@keyframes waveDriftB{ from{ transform:translate3d(0,2px,0);  } to{ transform:translate3d(-38px,0,0); } }

/* fill colours = the colour of the section that follows */
.wave--to-navy  path{ fill:var(--navy);  }
.wave--to-green path{ fill:var(--green); }
.wave--to-white path{ fill:var(--white); }

/* ==========================================================================
   3. AERATION BUBBLES – sparse rising bubbles in the dark sections,
   echoing the Belebungsbecken. Injected by main.js, paused off-screen.
   ========================================================================== */
.bubbles{
  position:absolute; inset:0; z-index:0;
  overflow:hidden; pointer-events:none;
  mask-image:linear-gradient(180deg,transparent,#000 18%,#000 82%,transparent);
  -webkit-mask-image:linear-gradient(180deg,transparent,#000 18%,#000 82%,transparent);
}
.bubbles span{
  position:absolute; bottom:-40px;
  border-radius:50%;
  background:radial-gradient(circle at 32% 30%,
             rgba(255,255,255,.55), rgba(120,200,235,.20) 55%, rgba(120,200,235,0) 72%);
  border:1px solid rgba(180,225,245,.18);
  animation-name:bubbleRise;
  animation-timing-function:linear;
  animation-iteration-count:infinite;
  will-change:transform,opacity;
}
@keyframes bubbleRise{
  0%   { transform:translate3d(0,0,0) scale(.85);            opacity:0; }
  12%  {                                                      opacity:.75; }
  50%  { transform:translate3d(14px,-46vh,0) scale(1);        opacity:.6; }
  88%  {                                                      opacity:.35; }
  100% { transform:translate3d(-10px,-96vh,0) scale(1.06);    opacity:0; }
}
.bubbles.is-paused span{ animation-play-state:paused; }

/* ==========================================================================
   4. TREATMENT CHAIN – the plant's process as a horizontal strip
   ========================================================================== */
.chain{
  list-style:none; margin:0; padding:0;
  /* desktop: all six fit, so nothing scrolls and no arrows are needed */
  display:grid; grid-template-columns:repeat(6,minmax(0,1fr));
  gap:clamp(1rem,.4rem + 1.6vw,1.75rem);
  counter-reset:step;
}
.chain__step{
  counter-increment:step;
  position:relative;
  padding:1.6rem 1.4rem 1.5rem;
  border-radius:18px;
  background:#fff;
  border:2px solid rgba(15,24,25,.12);
  transition:transform .3s var(--ease), border-color .3s var(--ease),
             box-shadow .3s var(--ease);
}
.chain__step::before{           /* numbered badge */
  content:counter(step);
  display:grid; place-items:center;
  width:44px; height:44px; margin-bottom:1rem;
  border-radius:50%; font-weight:700; font-size:1.05rem; color:#fff;
  background-image:linear-gradient(90deg,var(--grad-a),var(--grad-b));
  transition:transform .3s var(--ease);
}
.chain__step::after{            /* connector to the next step */
  content:""; position:absolute; top:calc(1.6rem + 22px); left:100%;
  width:clamp(1rem,.4rem + 1.6vw,1.75rem); height:2px;
  background:repeating-linear-gradient(90deg,
             rgba(15,24,25,.28) 0 6px, transparent 6px 12px);
}
.chain__step:last-child::after{ display:none; }
.chain__step:hover,
.chain__step:focus-within{
  transform:translateY(-4px);
  border-color:var(--grad-a);
  box-shadow:0 18px 36px -22px rgba(6,140,190,.75);
}
.chain__step:hover::before{ transform:scale(1.08); }

.chain__title{ margin:0 0 .5rem; font-size:1.1rem; font-weight:700; line-height:1.25; }
.chain__text { margin:0; font-size:.98rem; line-height:1.5; color:rgba(15,24,25,.72); }

/* horizontal scroll on narrow screens */
@media (max-width:1100px){
  .chain{
    /* narrow screens: a strip that scrolls on its own axis only.
       No negative margins – those pushed the page into horizontal scroll. */
    grid-template-columns:none;
    grid-auto-flow:column;
    grid-auto-columns:minmax(240px,80vw);
    overflow-x:auto;
    overscroll-behavior-x:contain;
    -webkit-overflow-scrolling:touch;
    scroll-snap-type:x proximity;
    padding-bottom:1rem;
    scrollbar-width:thin;
  }
  .chain__step{ scroll-snap-align:start; }
  .chain__step::after{ display:none; }
}
.chain-hint{ display:none; }   /* replaced by the arrow buttons */


/* ==========================================================================
   OFF-CANVAS DRAWER – shared pieces (head, close button, overlay)
   ========================================================================== */
:root{ --drawer-pad:1.6rem; }

/* head of the drawer: logo + close button. Hidden on desktop. */
.drawer__head{
  /* visible by default; the desktop query further down hides it.
     (Defining it as display:none here would lose to nothing — the
     responsive block sits EARLIER in the file.) */
  display:-webkit-box; display:-webkit-flex; display:flex;
  align-items:center; justify-content:space-between;
  gap:1rem; flex-wrap:wrap;
  padding:1.35rem var(--drawer-pad) 1.15rem;
  border-bottom:1px solid rgba(255,255,255,.16);
  position:sticky; top:0; z-index:2;
  background:var(--navy);
}
@media (min-width:1101px){ .drawer__head{ display:none; } }

.drawer__logo{ display:block; flex:1 1 auto; min-width:0; }
.drawer__logo img{ height:46px; width:auto; max-width:100%; }

/* a labelled pill, so it is obvious this closes the menu */
.drawer__close{
  flex:none;
  display:inline-flex; align-items:center; 
  height:44px; 
  width:44px; padding:0 1.05rem;
  background:rgba(255,255,255,.10); color:var(--white);
  border:1px solid rgba(255,255,255,.22); border-radius:999px;
  font:inherit; font-size:.9rem; font-weight:700; cursor:pointer;
  -webkit-transition:background-color .25s var(--ease), border-color .25s var(--ease);
          transition:background-color .25s var(--ease), border-color .25s var(--ease);
          justify-content: center;
}
.drawer__close:hover,
.drawer__close:focus-visible{ background:rgba(255,255,255,.20); border-color:rgba(255,255,255,.45); }
.drawer__close svg{ width:16px; height:16px; display:block; flex:none; }
.drawer__close-label{ white-space:nowrap; }

/* dimming layer behind the drawer */
.drawer-overlay{
  position:fixed; inset:0; z-index:99;
  touch-action:none;
  background:rgba(6,12,24,.55);
  -webkit-backdrop-filter:blur(2px);
          backdrop-filter:blur(2px);
  opacity:0; visibility:hidden;
  -webkit-transition:opacity .35s var(--ease), visibility .35s;
          transition:opacity .35s var(--ease), visibility .35s;
}
.drawer-overlay.is-open{ opacity:1; visibility:visible; }

/* ==========================================================================
   LANGUAGE SWITCHER ICONS
   Deliberately NOT flag emoji: Windows renders those as letter pairs, and a
   flag never maps cleanly onto a language anyway. Language codes in a round
   badge read the same on every platform.
   ========================================================================== */
.lang__globe{ width:19px; height:19px; flex:none; display:block; }
.lang__btn{ gap:.55rem; }

.lang__list button{
  display:-webkit-box; display:-webkit-flex; display:flex;
  align-items:center; gap:.85rem;
  padding:.7rem .8rem;
}
.lang__flag{
  flex:none;
  width:34px; height:34px; border-radius:50%;
  -o-object-fit:cover; object-fit:cover;
  -webkit-box-shadow:0 0 0 1px rgba(0,0,0,.22);
          box-shadow:0 0 0 1px rgba(0,0,0,.22);
}
/* higher specificity than the plain .lang__flag rule, so the light ring
   inside the dark drawer applies regardless of source order */
.nav__menu .lang__flag{
  -webkit-box-shadow:0 0 0 1px rgba(255,255,255,.38);
          box-shadow:0 0 0 1px rgba(255,255,255,.38);
}
.lang__check{
  width:16px; height:16px; margin-left:auto; flex:none;
  opacity:0; -webkit-transition:opacity .2s var(--ease); transition:opacity .2s var(--ease);
}
.lang__list button[aria-current="true"] .lang__check{ opacity:1; }

/* ==========================================================================
   BACK TO TOP – sticky button, bottom right
   ========================================================================== */
.gotop{
  position:fixed; z-index:95;
  right:clamp(1rem,1.6vw,2rem);
  bottom:clamp(1rem,1.6vw,2rem);
  width:52px; height:52px; padding:0;
  display:grid; place-items:center;
  border:0; border-radius:50%; cursor:pointer;
  color:var(--ink);
  background-image:linear-gradient(135deg,var(--grad-a),var(--grad-b));
  box-shadow:0 12px 30px -12px rgba(6,140,190,.85);
  opacity:0; visibility:hidden;
  -webkit-transform:translateY(14px) scale(.9);
          transform:translateY(14px) scale(.9);
  -webkit-transition:opacity .3s var(--ease), visibility .3s,
                     -webkit-transform .3s var(--ease), box-shadow .3s var(--ease);
          transition:opacity .3s var(--ease), visibility .3s,
                     transform .3s var(--ease), box-shadow .3s var(--ease);
}
.gotop.is-visible{
  opacity:1; visibility:visible;
  -webkit-transform:none; transform:none;
}
.gotop:hover,
.gotop:focus-visible{
  -webkit-transform:translateY(-3px); transform:translateY(-3px);
  box-shadow:0 18px 38px -14px rgba(6,140,190,.95);
}
.gotop:active{ -webkit-transform:translateY(0); transform:translateY(0); }
.gotop svg{ width:20px; height:20px; display:block; }
/* keep it out of the way while the drawer is open */
body.has-menu-open .gotop{ opacity:0; visibility:hidden; }

@media (max-width:560px){
  .gotop{ width:46px; height:46px; }
  .gotop svg{ width:18px; height:18px; }
}

/* ==========================================================================
   CROSS-BROWSER FALLBACK
   Firefox < 121 / older Safari have no :has(). main.js mirrors the checked
   state onto .is-checked so the card highlight works everywhere.
   ========================================================================== */
.choice.is-checked{ border-color:var(--grad-a); background:rgba(6,140,190,.06); }


/* ==========================================================================
   SLIDER ARROWS – for the horizontally scrolling treatment chain
   ========================================================================== */
.slider-nav{
  display:none;                 /* shown by JS only when the strip overflows */
  gap:.6rem; margin-top:1.25rem;
}
.slider-nav.is-active{ display:flex; }
.slider-nav__btn{
  width:48px; height:48px; padding:0; flex:none;
  display:grid; place-items:center;
  border:2px solid rgba(15,24,25,.18); border-radius:50%;
  background:#fff; color:var(--ink); cursor:pointer;
  -webkit-transition:border-color .2s var(--ease), background-color .2s var(--ease),
                     opacity .2s var(--ease), -webkit-transform .2s var(--ease);
          transition:border-color .2s var(--ease), background-color .2s var(--ease),
                     opacity .2s var(--ease), transform .2s var(--ease);
}
.slider-nav__btn:hover:not(:disabled),
.slider-nav__btn:focus-visible:not(:disabled){
  border-color:var(--grad-a); -webkit-transform:translateY(-2px); transform:translateY(-2px);
}
.slider-nav__btn:disabled{ opacity:.35; cursor:default; }
.slider-nav__btn svg{ width:18px; height:18px; display:block; }

/* ==========================================================================
   LIGHTBOX – click a photo to see it large
   ========================================================================== */
.lightbox{
  position:fixed; inset:0; z-index:200;
  display:grid; place-items:center;
  padding:clamp(1rem,4vw,3rem);
  background:rgba(6,12,24,.88);
  -webkit-backdrop-filter:blur(3px);
          backdrop-filter:blur(3px);
  opacity:0; visibility:hidden;
  -webkit-transition:opacity .28s var(--ease), visibility .28s;
          transition:opacity .28s var(--ease), visibility .28s;
}
.lightbox[hidden]{ display:none !important; }
.lightbox.is-open{ opacity:1; visibility:visible; }

.lightbox__img{
  max-width:min(1200px,100%); max-height:86vh;
  width:auto; height:auto;
  border-radius:16px;
  box-shadow:0 40px 90px -40px rgba(0,0,0,.9);
  -webkit-transform:scale(.96); transform:scale(.96);
  -webkit-transition:-webkit-transform .28s var(--ease); transition:transform .28s var(--ease);
}
.lightbox.is-open .lightbox__img{ -webkit-transform:none; transform:none; }

.lightbox__close{
  position:absolute; top:clamp(.75rem,2vw,1.5rem); right:clamp(.75rem,2vw,1.5rem);
  width:52px; height:52px; padding:0;
  display:grid; place-items:center;
  border:0; border-radius:50%; cursor:pointer;
  background:rgba(255,255,255,.14); color:#fff;
  -webkit-transition:background-color .2s var(--ease), -webkit-transform .2s var(--ease);
          transition:background-color .2s var(--ease), transform .2s var(--ease);
}
.lightbox__close:hover,
.lightbox__close:focus-visible{ background:rgba(255,255,255,.28); -webkit-transform:rotate(90deg); transform:rotate(90deg); }
.lightbox__close svg{ width:20px; height:20px; display:block; }

/* photos become obviously clickable */
.media--zoom img{ cursor:-webkit-zoom-in; cursor:zoom-in; }

/* ==========================================================================
   ABOUT US
   ========================================================================== */
.about-grid{ display:grid; grid-template-columns:repeat(auto-fit,minmax(240px,1fr)); gap:clamp(1.5rem,1rem + 2vw,2.75rem); margin-top:2.5rem; }
.about-card{
  padding:1.75rem 1.6rem;
  border-radius:18px;
  background:#fff;
  border:2px solid rgba(15,24,25,.12);
  -webkit-transition:border-color .3s var(--ease), -webkit-transform .3s var(--ease);
          transition:border-color .3s var(--ease), transform .3s var(--ease);
}
.about-card:hover{ border-color:var(--grad-a); -webkit-transform:translateY(-3px); transform:translateY(-3px); }
.about-card h3{ margin:0 0 .6rem; font-size:1.15rem; font-weight:700; }
.about-card p{ margin:0; font-size:1rem; line-height:1.55; color:rgba(15,24,25,.74); }

/* ==========================================================================
   FOOTER LINK LIST
   ========================================================================== */
.footer__links{ list-style:none; margin:0 0 1.4rem; padding:0; display:grid; gap:.55rem; }
.footer__links a{
  text-decoration:none; border-bottom:1px solid rgba(255,255,255,.28);
  padding-bottom:2px;
  -webkit-transition:border-color .2s var(--ease), color .2s var(--ease);
          transition:border-color .2s var(--ease), color .2s var(--ease);
}
.footer__links a:hover,
.footer__links a:focus-visible{ border-color:var(--grad-b); color:#CFE79A; }
.footer__col-title{
  margin:0 0 1rem; font-size:.85rem; font-weight:700;
  letter-spacing:.14em; text-transform:uppercase; color:var(--grad-b);
}
.footer .grid--split{ grid-template-columns:1.15fr .85fr .9fr; }
@media (max-width:900px){ .footer .grid--split{ grid-template-columns:1fr; } }

/* ==========================  accessibility  ========================== */
@media (prefers-reduced-motion:reduce){
  html{ scroll-behavior:auto; }
  *,*::before,*::after{
    animation-duration:.001ms !important;
    transition-duration:.001ms !important;
  }
  .reveal{ opacity:1; transform:none; }
  .cursor-glow{ display:none; }
  .bubbles{ display:none; }
  .wave__back,.wave__front{ animation:none; }
  .gotop{ transition:none; }
  .media--tilt picture,
  .media--tilt img{ transform:none !important; }
}

@media print{
  .nav,.glow-blue::after,.media--glow::before,.has-blueprint::before,.cursor-glow,
  .progress,.wave,.bubbles,.gotop,.drawer-overlay,.slider-nav,.lightbox{ display:none !important; }
  body{ color:#000; background:#fff; }
}