/* ==========================================================================
   SKmaths — Charte commune
   ========================================================================== */

:root {
  --bg: #f4ede0;
  --bg-deep: #ebe1cc;
  --ink: #1a1d2e;
  --ink-soft: #5a5d6e;
  --paper: #fbf6ec;
  --grid: #dfd5bf;
  --cos: #2c4870;
  --sin: #a83246;
  --tan: #b87a2c;
  --serif: 'EB Garamond', Georgia, serif;
  --display: 'Fraunces', 'EB Garamond', Georgia, serif;
  --mono: 'JetBrains Mono', ui-monospace, monospace;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--serif);
  font-size: 18px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
  background-image:
    radial-gradient(circle at 20% 10%, rgba(184, 122, 44, 0.04) 0%, transparent 40%),
    radial-gradient(circle at 80% 70%, rgba(44, 72, 112, 0.04) 0%, transparent 50%);
}

a { color: inherit; text-decoration: none; }
h1, h2, h3, h4 { font-family: var(--display); font-weight: 500; }

.container { max-width: 1180px; margin: 0 auto; padding: 0 1.5rem; }
.container-narrow { max-width: 860px; margin: 0 auto; padding: 0 1.5rem; }

.eyebrow {
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

/* ===== NAVIGATION ===== */
nav.top {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(244, 237, 224, 0.92);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--grid);
}
nav.top .row {
  display: flex; align-items: center; justify-content: space-between;
  padding: 1rem 0;
}
.brand {
  display: flex; align-items: center; gap: 0.7rem;
  font-family: var(--display); font-weight: 600;
  font-size: 1.15rem; letter-spacing: -0.01em;
}
.brand-mark {
  width: 38px; height: 38px; border-radius: 50%;
  background: var(--ink); color: var(--bg);
  display: grid; place-items: center;
  font-style: italic; font-family: var(--display);
  font-weight: 700; font-size: 1.1rem;
  letter-spacing: -0.04em;
}
.brand-mark::after { content: "SK"; }
.nav-links {
  display: flex; gap: 1.6rem;
  font-style: italic; font-size: 1rem;
}
.nav-links a { position: relative; padding: 0.2rem 0; }
.nav-links a::after {
  content: "";
  position: absolute; left: 0; right: 0; bottom: -2px;
  height: 1px; background: var(--ink);
  transform: scaleX(0); transform-origin: left;
  transition: transform 0.3s ease;
}
.nav-links a:hover::after,
.nav-links a.active::after { transform: scaleX(1); }
.nav-cta {
  padding: 0.55rem 1.1rem; background: var(--ink); color: var(--bg);
  font-family: var(--mono); font-size: 0.75rem;
  letter-spacing: 0.12em; text-transform: uppercase;
  border-radius: 2px; transition: background 0.2s;
}
.nav-cta:hover { background: var(--cos); }
.nav-toggle { display: none; background: none; border: none; cursor: pointer; padding: 0.5rem; }
.nav-toggle span { display: block; width: 22px; height: 1.5px; background: var(--ink); margin: 5px 0; }

@media (max-width: 880px) {
  .nav-links, .nav-cta { display: none; }
  .nav-toggle { display: block; }
}

/* ===== BOUTONS ===== */
.btn {
  padding: 0.85rem 1.6rem;
  font-family: var(--mono); font-size: 0.78rem;
  letter-spacing: 0.14em; text-transform: uppercase;
  border-radius: 2px; border: 1.5px solid var(--ink);
  cursor: pointer; transition: all 0.2s ease;
  display: inline-flex; align-items: center; gap: 0.5rem;
}
.btn-primary { background: var(--ink); color: var(--bg); }
.btn-primary:hover { background: var(--cos); border-color: var(--cos); }
.btn-ghost { background: transparent; color: var(--ink); }
.btn-ghost:hover { background: var(--ink); color: var(--bg); }
.btn-small { padding: 0.55rem 1rem; font-size: 0.72rem; }

/* ===== FIL D'ARIANE ===== */
.breadcrumb {
  padding: 1.5rem 0 0.5rem;
  font-family: var(--mono); font-size: 0.7rem;
  letter-spacing: 0.14em; text-transform: uppercase;
  color: var(--ink-soft);
}
.breadcrumb a { transition: color 0.2s; }
.breadcrumb a:hover { color: var(--cos); }
.breadcrumb .sep { margin: 0 0.6rem; opacity: 0.5; }

/* ===== TÊTE DE PAGE ===== */
.page-head {
  padding: 2rem 0 3.5rem;
  border-bottom: 1px solid var(--grid);
  margin-bottom: 3.5rem;
}
.page-head .eyebrow-row {
  display: flex; align-items: baseline; gap: 0.8rem;
  margin-bottom: 1.2rem;
}
.page-head .eyebrow-row .line {
  flex: 0 0 50px; height: 1px;
  background: var(--ink); opacity: 0.4;
}
.page-head h1 {
  font-size: clamp(2.2rem, 5vw, 3.6rem);
  line-height: 1.02; letter-spacing: -0.02em;
  margin: 0; font-weight: 400;
}
.page-head h1 em { font-style: italic; color: var(--cos); font-weight: 500; }
.page-head .lede {
  font-size: 1.1rem; color: var(--ink-soft);
  margin: 1.2rem 0 0; max-width: 620px; line-height: 1.55;
}

/* ===== SECTION HEAD ===== */
.section-head {
  display: flex; align-items: flex-end; justify-content: space-between;
  gap: 2rem; margin-bottom: 2.5rem; flex-wrap: wrap;
}
.section-head .left { flex: 1; min-width: 280px; }
.section-head h2 {
  font-size: clamp(1.7rem, 3.2vw, 2.4rem);
  margin: 0.5rem 0 0; font-weight: 400;
  letter-spacing: -0.02em; line-height: 1.1;
}
.section-head h2 em { font-style: italic; color: var(--cos); font-weight: 500; }

/* ===== FOOTER ===== */
footer {
  background: var(--paper);
  border-top: 1px solid var(--grid);
  padding: 3.5rem 0 1.5rem; margin-top: 5rem;
}
.footer-grid {
  display: grid; grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 2.5rem; margin-bottom: 3rem;
}
@media (max-width: 880px) { .footer-grid { grid-template-columns: 1fr 1fr; } }
@media (max-width: 520px) { .footer-grid { grid-template-columns: 1fr; } }
.footer-brand .brand { margin-bottom: 1rem; }
.footer-tagline {
  color: var(--ink-soft); font-size: 0.95rem;
  line-height: 1.5; max-width: 320px; font-style: italic;
}
.footer-col h4 {
  font-family: var(--mono); font-size: 0.7rem;
  letter-spacing: 0.18em; text-transform: uppercase;
  color: var(--ink-soft); margin: 0 0 1.2rem; font-weight: 500;
}
.footer-col ul { list-style: none; padding: 0; margin: 0; }
.footer-col li { margin-bottom: 0.6rem; }
.footer-col a { font-style: italic; transition: color 0.2s; }
.footer-col a:hover { color: var(--cos); }
.footer-bottom {
  padding-top: 1.5rem; border-top: 1px solid var(--grid);
  display: flex; justify-content: space-between; align-items: center;
  font-family: var(--mono); font-size: 0.7rem;
  color: var(--ink-soft); letter-spacing: 0.08em;
  flex-wrap: wrap; gap: 1rem;
}

/* ===== DÉCORATIONS COMMUNES ===== */
.decoration-numeral {
  position: absolute;
  font-family: var(--display); font-style: italic;
  color: var(--ink); opacity: 0.04;
  font-size: 16rem; font-weight: 700;
  pointer-events: none; line-height: 1; user-select: none;
}

/* ===== TAGS / BADGES ===== */
.tag {
  display: inline-block; padding: 0.25rem 0.6rem;
  font-family: var(--mono); font-size: 0.62rem;
  letter-spacing: 0.16em; text-transform: uppercase;
  border-radius: 2px;
}
.tag-cos { background: rgba(44, 72, 112, 0.08); color: var(--cos); }
.tag-sin { background: rgba(168, 50, 70, 0.08); color: var(--sin); }
.tag-tan { background: rgba(184, 122, 44, 0.1); color: var(--tan); }
.tag-ink { background: rgba(26, 29, 46, 0.08); color: var(--ink); }