:root {
  --ink: #0b0c0b;
  --ink-soft: #141614;
  --paper: #f4f1ea;
  --paper-dim: #b9b6ad;
  --mint: #5cf2a9;
  --citrus: #d8ff3e;
  --sky: #74d0ff;
  --rose: #ff8fb1;
  --accent: var(--mint);
  --accent-ink: var(--accent);
  --bg: var(--ink);
  --fg: var(--paper);
  --edge: clamp(1.25rem, 4vw, 4rem);
  --maxw: 1600px;
  --font-display: "Bricolage Grotesque", "Arial Narrow", sans-serif;
  --font-body: "Inter", system-ui, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, "SFMono-Regular", "Menlo", monospace;
  --ease: cubic-bezier(.16, 1, .3, 1);
  --chap: var(--mint);
}

/* Même clé de stockage/logique que public/site.js (charly.theme) : une
   petite ligne dans solutions.js applique cette classe au chargement pour
   que ces pages respectent le thème choisi sur le reste du site. */
body.theme-paper {
  --bg: var(--paper);
  --fg: var(--ink);
  --paper-dim: #6f6d64;
  --accent-ink: #0a7d47;
}

body[data-theme="mint"] { --chap: var(--mint); }
body[data-theme="citrus"] { --chap: var(--citrus); }
body[data-theme="sky"] { --chap: var(--sky); }
body[data-theme="rose"] { --chap: var(--rose); }
body:not(.theme-paper)[data-theme="citrus"] { --accent-ink: var(--citrus); }
body:not(.theme-paper)[data-theme="sky"] { --accent-ink: var(--sky); }
body:not(.theme-paper)[data-theme="rose"] { --accent-ink: var(--rose); }

* { margin: 0; padding: 0; box-sizing: border-box; }
html, body { height: 100%; }

body {
  background:
    radial-gradient(60vw 60vh at 82% 0%, color-mix(in srgb, var(--chap) 14%, transparent), transparent 60%),
    radial-gradient(50vw 50vh at 0% 100%, color-mix(in srgb, var(--chap) 8%, transparent), transparent 65%),
    var(--bg);
  color: var(--fg);
  font-family: var(--font-body);
  font-size: clamp(.95rem, .9rem + .2vw, 1.05rem);
  line-height: 1.55;
  min-height: 100%;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  transition: background .6s var(--ease), color .6s var(--ease);
}

a { color: inherit; }

.sol-grain {
  position: fixed; inset: 0; z-index: 50; pointer-events: none;
  opacity: .05; mix-blend-mode: overlay;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='120' height='120'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2' stitchTiles='stitch'/></filter><rect width='100%25' height='100%25' filter='url(%23n)'/></svg>");
}

.section-eyebrow {
  font-size: .78rem;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--accent-ink);
  margin-bottom: 1.4rem;
}

.js .reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity .8s var(--ease), transform .8s var(--ease);
}
.js .reveal.is-in { opacity: 1; transform: none; }

/* ---- nav ---- */
.sol-nav {
  position: sticky; top: 0; z-index: 20;
  display: flex; align-items: center; justify-content: space-between;
  gap: 1rem;
  padding: 1.4rem var(--edge);
  background: color-mix(in srgb, var(--bg) 78%, transparent);
  backdrop-filter: blur(10px); -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid color-mix(in srgb, var(--fg) 10%, transparent);
}
.sol-nav__brand {
  font-family: var(--font-mono); font-weight: 700; font-size: .95rem; text-transform:uppercase;
  letter-spacing: .04em; text-decoration: none; color: var(--fg);
}
.sol-nav__cross { color: var(--mint); }
.sol-nav__right { display: flex; align-items: center; gap: 1.1rem; }
.sol-nav__back {
  font-family: var(--font-mono); font-size: .78rem; letter-spacing: .04em;
  text-decoration: none; color: var(--paper-dim);
  transition: color .25s var(--ease);
}
.sol-nav__back:hover { color: var(--accent-ink); }

.sol-lang {
  display: flex; align-items: stretch;
  border: 1px solid color-mix(in srgb, var(--fg) 18%, transparent);
  border-radius: 999px;
  padding: 2px;
}
.sol-lang button {
  appearance: none; background: none; border: 0; margin: 0; cursor: pointer;
  padding: .3rem .55rem;
  border-radius: 999px;
  font-family: var(--font-mono); font-weight: 700; font-size: .64rem;
  letter-spacing: .06em;
  color: var(--paper-dim);
  transition: color .25s var(--ease), background .25s var(--ease);
}
.sol-lang button:hover { color: var(--fg); }
.sol-lang button.is-active { background: var(--accent); color: var(--ink); }

.sol-theme {
  display: grid; place-items: center;
  width: 2rem; height: 2rem;
  border: 1px solid color-mix(in srgb, var(--fg) 18%, transparent);
  border-radius: 50%;
  background: transparent;
  color: var(--fg);
  cursor: pointer;
  transition: border-color .25s var(--ease), color .25s var(--ease);
}
.sol-theme:hover { border-color: color-mix(in srgb, var(--accent-ink) 55%, transparent); color: var(--accent-ink); }
.sol-theme svg { width: 14px; height: 14px; fill: none; stroke: currentColor; stroke-width: 1.6; stroke-linecap: round; stroke-linejoin: round; }
.sol-theme__moon { fill: currentColor; stroke: none; }
.sol-theme__sun { display: none; }
body.theme-paper .sol-theme__moon { display: none; }
body.theme-paper .sol-theme__sun { display: block; }

/* ---- hero ---- */
.sol-hero {
  position: relative;
  max-width: var(--maxw); margin: 0 auto;
  padding: clamp(5rem, 15vh, 9rem) var(--edge) clamp(3.5rem, 9vh, 5.5rem);
  overflow: hidden;
}
.sol-hero__spot {
  position: absolute;
  width: 60vmax; height: 60vmax;
  right: -20vmax; top: -30vmax;
  background: radial-gradient(circle, var(--chap) 0%, transparent 62%);
  opacity: .18;
  filter: blur(20px);
  pointer-events: none;
}
.sol-hero__num {
  position: absolute;
  right: var(--edge); top: clamp(.5rem, 2vh, 2rem);
  font-family: var(--font-mono); font-weight: 700;
  font-size: clamp(5rem, 16vw, 13rem); line-height: 1;
  color: transparent; -webkit-text-stroke: 1.5px var(--fg);
  opacity: .1; pointer-events: none;
}
.sol-hero__title {
  position: relative;
  font-family: var(--font-display); font-weight: 700;
  font-size: clamp(2.4rem, 6.5vw, 5.2rem); line-height: .98; letter-spacing: -.02em;
  max-width: 18ch;
}
.sol-hero__sub {
  position: relative;
  margin-top: 1.6rem; font-size: 1.1rem; line-height: 1.6;
  color: var(--paper-dim); max-width: 52ch;
}

/* ---- feature list ---- */
.sol-list {
  max-width: var(--maxw); margin: 0 auto;
  padding: 0 var(--edge) clamp(4rem, 10vh, 7rem);
  display: grid; gap: 1.1rem;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
}
.sol-item {
  display: grid; grid-template-columns: 3rem 1fr; gap: 1.2rem;
  padding: 1.8rem 1.8rem 2rem;
  background: linear-gradient(155deg, color-mix(in srgb, var(--fg) 4%, var(--bg)) 0%, var(--bg) 65%);
  border: 1px solid color-mix(in srgb, var(--fg) 10%, transparent);
  border-radius: 4px;
  transition: border-color .3s var(--ease), transform .3s var(--ease), box-shadow .3s var(--ease);
}
.sol-item:hover {
  border-color: color-mix(in srgb, var(--chap) 45%, transparent);
  transform: translateY(-3px);
  box-shadow: 0 20px 50px -25px color-mix(in srgb, var(--chap) 35%, transparent);
}
.sol-item__num {
  font-family: var(--font-mono); font-size: .78rem; letter-spacing: .06em;
  color: var(--accent-ink); padding-top: .25rem;
}
.sol-item__name {
  font-family: var(--font-display); font-weight: 600; font-size: 1.22rem;
  line-height: 1.2; margin-bottom: .6rem;
}
.sol-item__desc {
  font-size: .9rem; line-height: 1.6; color: var(--paper-dim);
}

/* ---- pager ---- */
.sol-pager {
  max-width: var(--maxw); margin: 0 auto;
  padding: 0 var(--edge) clamp(5rem, 12vh, 7rem);
  display: grid; grid-template-columns: 1fr auto 1fr; align-items: stretch; gap: 1rem;
}
.sol-pager__link {
  text-decoration: none; display: flex; flex-direction: column; justify-content: center; gap: .4rem;
  padding: 1.3rem 1.5rem;
  border: 1px solid color-mix(in srgb, var(--fg) 12%, transparent);
  border-radius: 4px;
  background: color-mix(in srgb, var(--fg) 4%, var(--bg));
  transition: border-color .3s var(--ease), background .3s var(--ease), transform .3s var(--ease);
}
.sol-pager__link:hover {
  border-color: color-mix(in srgb, var(--chap) 50%, transparent);
  background: color-mix(in srgb, var(--chap) 8%, var(--bg));
  transform: translateY(-2px);
}
.sol-pager__link--next { text-align: right; align-items: flex-end; }
.sol-pager__label {
  font-family: var(--font-mono); font-size: .72rem; letter-spacing: .08em;
  text-transform: uppercase; color: var(--accent-ink);
}
.sol-pager__title { font-family: var(--font-display); font-weight: 600; font-size: 1.05rem; }
.sol-pager__link--home {
  flex-direction: row; align-items: center; justify-content: center; gap: .6rem;
  text-align: center;
  font-family: var(--font-mono); font-size: .78rem; letter-spacing: .05em;
  color: var(--paper-dim); white-space: nowrap;
}
.sol-pager__link--home:hover { color: var(--fg); }
.sol-pager__grid {
  display: grid; grid-template-columns: 1fr 1fr; gap: 3px;
  width: 12px; height: 12px;
}
.sol-pager__grid i {
  display: block; background: currentColor; border-radius: 1px;
  opacity: .7;
}

@media (max-width: 720px) {
  .sol-pager { grid-template-columns: 1fr; }
  .sol-pager__link--next { text-align: left; align-items: flex-start; }
  .sol-pager__link--home { order: -1; }
  .sol-nav__back { font-size: 0; }
  .sol-nav__back::before { content: "\2190"; font-size: 1rem; }
  .sol-hero__num { font-size: clamp(4rem, 22vw, 7rem); top: .5rem; }
}