/* =========================================================================
   Data Lab — design system CSS vanilla (aucun framework, aucune dépendance)
   ========================================================================= */

:root {
  --color-bg: #f8fafc;
  --color-surface: #ffffff;
  --color-border: #e2e8f0;
  --color-text: #1e293b;
  --color-text-muted: #64748b;
  --color-text-faint: #94a3b8;

  --color-primary: #2563eb;
  --color-primary-dark: #1d4ed8;
  --color-primary-active: #1e40af;
  --color-primary-light: #eff6ff;

  --color-secondary-light: #f1f5f9;

  --color-success: #16a34a;
  --color-success-dark: #15803d;
  --color-success-active: #14532d;
  --color-success-light: #f0fdf4;
  --color-success-border: #bbf7d0;
  --color-success-text: #166534;

  --color-error: #dc2626;
  --color-error-light: #fdecea;

  --color-warning-bg: #fffbeb;
  --color-warning-border: #fde68a;
  --color-warning-text: #92400e;

  --color-debutant: #166534;
  --color-debutant-bg: #dcfce7;
  --color-intermediaire: #92400e;
  --color-intermediaire-bg: #fef3c7;
  --color-avance: #991b1b;
  --color-avance-bg: #fee2e2;

  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 12px;

  --shadow-sm: 0 1px 3px rgba(15, 23, 42, 0.08);
  --shadow-md: 0 8px 20px rgba(15, 23, 42, 0.1);
  --shadow-lg: 0 8px 24px rgba(15, 23, 42, 0.12);

  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-mono: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
}

* { box-sizing: border-box; }

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

body {
  margin: 0;
  font-family: var(--font-sans);
  -webkit-font-smoothing: antialiased;
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.55;
}

.container {
  max-width: 1180px;
  margin: 0 auto;
  padding: 0 24px;
}

a { color: var(--color-primary); text-decoration: none; }
a:hover { color: var(--color-primary-dark); }

h1, h2, h3, h4 { line-height: 1.25; margin: 0 0 12px; letter-spacing: -0.01em; }
h1 { font-size: 1.9rem; font-weight: 800; }
h2 { font-size: 1.35rem; font-weight: 800; }
h3 { font-size: 1.05rem; font-weight: 700; }

code {
  font-family: var(--font-mono);
  background: var(--color-primary-light);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.85em;
}

@keyframes fade-in {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ---------- Header / Nav ---------- */

.site-header {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 20;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  height: 64px;
}

.header-left { display: flex; align-items: center; gap: 28px; }

.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 17px; color: var(--color-text); }
.brand:hover { color: var(--color-text); }

.brand-mark {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-md);
  background: var(--color-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.main-nav { display: flex; align-items: center; gap: 20px; }

.nav-link { color: #334155; font-weight: 600; font-size: 14px; }
.nav-link:hover { color: var(--color-primary); }

.nav-dropdown { position: relative; }
.nav-dropdown summary {
  list-style: none;
  cursor: pointer;
  font-weight: 600;
  font-size: 14px;
  color: #334155;
  padding: 6px 4px;
  display: inline-flex;
  align-items: center;
  gap: 5px;
}
.nav-dropdown summary:hover { color: var(--color-primary); }
.nav-dropdown summary::-webkit-details-marker { display: none; }
.nav-dropdown summary::after { content: "▾"; font-size: 11px; }
.nav-dropdown[open] summary::after { content: "▴"; }

.nav-dropdown ul {
  position: absolute;
  left: 0;
  top: 100%;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 10px;
  box-shadow: var(--shadow-lg);
  list-style: none;
  margin: 4px 0 0;
  padding: 6px;
  min-width: 230px;
  z-index: 30;
}
.nav-dropdown ul li a {
  display: block;
  padding: 9px 12px;
  border-radius: var(--radius-sm);
  color: var(--color-text);
  font-size: 14px;
  font-weight: 500;
}
.nav-dropdown ul li a:hover {
  background: var(--color-secondary-light);
  color: var(--color-text);
}

/* ---------- Hero ---------- */

.home-page { max-width: 1180px; margin: 0 auto; padding: 64px 24px 40px; animation: fade-in 0.3s ease-out; }

.hero { max-width: 680px; margin: 0 auto 20px; text-align: center; }
.subtitle { font-size: 1.1rem; color: var(--color-text-muted); margin: 0 0 10px; line-height: 1.6; }
.hero-desc { color: var(--color-text-faint); font-size: 0.875rem; margin: 0; }

/* ---------- Cards ---------- */

.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  padding: 24px;
}

.study-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
  padding: 40px 0 0;
}

.study-card {
  display: flex;
  flex-direction: column;
  padding: 26px;
  transition: transform 0.2s ease-out, box-shadow 0.2s ease-out, border-color 0.2s ease-out;
  animation: fade-in 0.4s ease both;
}
.study-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  border-color: #93c5fd;
}
.study-card-top { display: flex; align-items: flex-start; justify-content: space-between; margin-bottom: 16px; }
.study-card-icon {
  width: 48px;
  height: 48px;
  border-radius: 10px;
  background: var(--color-primary-light);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.study-card h3 { font-size: 1.1rem; margin: 0 0 8px; }
.study-card p { color: var(--color-text-muted); font-size: 0.9rem; line-height: 1.55; flex-grow: 1; margin: 0 0 20px; }
.study-card .btn { width: 100%; justify-content: center; }

/* ---------- How it works ---------- */

.how-it-works { margin-top: 64px; padding: 40px 0 56px; border-top: 1px solid var(--color-border); }
.how-it-works h2 { text-align: center; font-size: 1.4rem; margin-bottom: 32px; }
.how-it-works-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 24px;
  max-width: 900px;
  margin: 0 auto;
}
.how-it-works-step { text-align: center; }
.how-it-works-num {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--color-primary);
  color: #fff;
  font-weight: 800;
  font-size: 18px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 12px;
}
.how-it-works-step h4 { font-size: 15px; margin: 0 0 6px; }
.how-it-works-step p { font-size: 13px; color: var(--color-text-muted); margin: 0; }

/* ---------- Badges ---------- */

.badge {
  display: inline-block;
  font-size: 11px;
  font-weight: 700;
  padding: 4px 10px;
  border-radius: 999px;
  background: var(--color-border);
  color: var(--color-text);
}
.badge-debutant { background: var(--color-debutant-bg); color: var(--color-debutant); }
.badge-intermediaire { background: var(--color-intermediaire-bg); color: var(--color-intermediaire); }
.badge-avance { background: var(--color-avance-bg); color: var(--color-avance); }

/* ---------- Buttons ---------- */

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  border: 1px solid transparent;
  border-radius: var(--radius-md);
  padding: 11px 16px;
  font: inherit;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s ease;
}
.btn:hover { text-decoration: none; }
.btn:focus-visible { outline: 2px solid var(--color-primary); outline-offset: 2px; }

.btn-primary { background: var(--color-primary); color: #fff; }
.btn-primary:hover { background: var(--color-primary-dark); }
.btn-primary:active { background: var(--color-primary-active); }
.btn-primary:focus-visible { box-shadow: 0 0 0 4px rgba(37, 99, 235, 0.18); }

.btn-success { background: var(--color-success); color: #fff; }
.btn-success:hover { background: var(--color-success-dark); }
.btn-success:active { background: var(--color-success-active); }
.btn-success:focus-visible { box-shadow: 0 0 0 4px rgba(22, 163, 74, 0.18); }

.btn-secondary { background: var(--color-surface); color: var(--color-text); border-color: #cbd5e1; }
.btn-secondary:hover { background: var(--color-secondary-light); }

.btn-ghost { background: transparent; color: var(--color-text-muted); border-color: transparent; }
.btn-ghost:hover { color: var(--color-text); }

.btn-lg { padding: 14px 20px; font-size: 15px; font-weight: 700; width: 100%; justify-content: center; }

/* ---------- Breadcrumb ---------- */

.breadcrumb { font-size: 13px; color: var(--color-text-faint); margin-bottom: 20px; }
.breadcrumb a { color: var(--color-text-faint); }
.breadcrumb a:hover { color: var(--color-primary); }
.breadcrumb .current { color: #334155; font-weight: 600; }

/* ---------- Forms ---------- */

.form-page { max-width: 1180px; margin: 0 auto; padding: 32px 24px 64px; animation: fade-in 0.3s ease-out; }

.form-layout { display: grid; grid-template-columns: 1.5fr 1fr; gap: 32px; align-items: start; }

.form-heading { display: flex; align-items: center; gap: 10px; margin-bottom: 8px; }
.form-heading h1 { margin: 0; }
.form-intro { color: var(--color-text-muted); margin: 0 0 28px; font-size: 15px; line-height: 1.5; }

.form-card { display: flex; flex-direction: column; gap: 24px; padding: 28px; }

.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.form-row-wrap { display: flex; gap: 16px; flex-wrap: wrap; }
.form-row-wrap > * { flex: 1; min-width: 150px; }

.form-group { display: flex; flex-direction: column; gap: 8px; }
.form-group label { font-weight: 600; font-size: 14px; }

.form-group input,
.form-group select {
  font: inherit;
  padding: 10px 12px;
  border: 1px solid #cbd5e1;
  border-radius: var(--radius-md);
  background: var(--color-surface);
  color: var(--color-text);
  font-size: 14px;
  width: 100%;
}
.form-group input:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}
.form-group input[type="radio"] { width: auto; }

.radio-row { display: flex; gap: 12px; }
.radio-option { display: flex; align-items: center; gap: 6px; font-size: 14px; font-weight: 500; cursor: pointer; width: auto; }

.field-hint { margin: 0; font-size: 12px; color: var(--color-text-faint); }
.back-link { display: inline-block; margin-top: 4px; font-size: 13px; color: var(--color-text-muted); text-align: center; }
.back-link:hover { color: var(--color-primary); }

.alert {
  padding: 12px 14px;
  border-radius: var(--radius-md);
  font-size: 0.9rem;
  margin: 0 0 4px;
}
.alert-error { background: var(--color-error-light); color: var(--color-error); }

/* ---------- Study sidebar (form + methodology) ---------- */

.study-sidebar {
  position: sticky;
  top: 88px;
  background: var(--color-secondary-light);
  border-radius: var(--radius-lg);
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 18px;
}
.study-sidebar h3 {
  font-size: 14px;
  margin: 0;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  color: #475569;
}
.study-sidebar-defs { display: flex; flex-direction: column; gap: 10px; }
.study-sidebar-defs p { font-size: 13px; margin: 0; line-height: 1.5; }
.study-sidebar-defs strong { color: var(--color-text); }
.study-sidebar-defs span { color: #475569; }

.study-sidebar-label {
  font-size: 12px;
  font-weight: 700;
  color: #475569;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  margin: 0 0 8px;
}
.study-sidebar-categories { display: flex; flex-direction: column; gap: 6px; }
.study-sidebar-category {
  display: flex;
  justify-content: space-between;
  gap: 8px;
  font-size: 12.5px;
  background: var(--color-surface);
  border-radius: 6px;
  padding: 7px 10px;
}
.study-sidebar-category strong { font-weight: 600; }
.study-sidebar-category span { color: var(--color-text-muted); text-align: right; }

.study-sidebar-tip {
  background: var(--color-warning-bg);
  border: 1px solid var(--color-warning-border);
  border-radius: var(--radius-md);
  padding: 12px 14px;
}
.study-sidebar-tip p { font-size: 12.5px; margin: 0; color: var(--color-warning-text); line-height: 1.5; }

/* ---------- Preview page ---------- */

.preview-page { max-width: 1100px; margin: 0 auto; padding: 32px 24px 64px; animation: fade-in 0.3s ease-out; }

.preview-success {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
  background: var(--color-success-light);
  border: 1px solid var(--color-success-border);
  border-radius: 10px;
  padding: 16px 20px;
  margin-bottom: 24px;
}
.preview-success-left { display: flex; align-items: center; gap: 12px; }
.preview-success p { margin: 0; font-size: 15px; font-weight: 600; color: var(--color-success-text); }
.preview-session-badge {
  font-size: 12px;
  font-weight: 700;
  background: var(--color-debutant-bg);
  color: var(--color-success-text);
  padding: 5px 10px;
  border-radius: 999px;
}

.preview-tab-input { position: absolute; opacity: 0; width: 1px; height: 1px; }

.preview-tabs { display: flex; gap: 4px; border-bottom: 1px solid var(--color-border); margin-bottom: 20px; }
.preview-tab {
  background: none;
  border: none;
  padding: 11px 16px;
  font: inherit;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  color: var(--color-text-muted);
  border-bottom: 2px solid transparent;
}
#tab-data:checked ~ .preview-tabs label[for="tab-data"],
#tab-structure:checked ~ .preview-tabs label[for="tab-structure"] {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
}

.preview-tab-panel { display: none; }
#tab-data:checked ~ .preview-tab-panels #panel-data,
#tab-structure:checked ~ .preview-tab-panels #panel-structure { display: block; }

.table-scroll { overflow: auto; max-height: 420px; border: 1px solid var(--color-border); border-radius: 10px; box-shadow: var(--shadow-sm); }

.table-preview { width: 100%; border-collapse: collapse; font-size: 13px; min-width: 600px; }
.table-preview thead th {
  position: sticky;
  top: 0;
  background: var(--color-secondary-light);
  text-align: right;
  padding: 11px 14px;
  font-weight: 700;
  color: var(--color-text);
  border-bottom: 2px solid var(--color-border);
  white-space: nowrap;
}
.table-preview tbody td {
  padding: 9px 14px;
  color: #334155;
  border-bottom: 1px solid #f1f5f9;
  white-space: nowrap;
  text-align: right;
}
.table-preview tbody tr:nth-child(even) { background: var(--color-bg); }
.table-preview tbody tr:hover { background: var(--color-primary-light); }

.preview-table-meta { display: flex; align-items: center; justify-content: space-between; margin-top: 12px; flex-wrap: wrap; gap: 10px; }
.preview-table-meta p { font-size: 13px; color: var(--color-text-muted); margin: 0; }

.structure-table { background: var(--color-surface); border: 1px solid var(--color-border); border-radius: 10px; overflow: hidden; }
.structure-row {
  display: grid;
  grid-template-columns: 1fr 100px 2fr 1fr;
  gap: 14px;
  padding: 13px 18px;
  border-bottom: 1px solid #f1f5f9;
  align-items: center;
}
.structure-row:last-child { border-bottom: none; }
.structure-row code { font-size: 13px; font-weight: 600; background: none; padding: 0; }
.structure-type {
  font-size: 11px;
  font-weight: 700;
  padding: 3px 8px;
  border-radius: 5px;
  background: var(--color-primary-light);
  color: var(--color-primary);
  width: fit-content;
}
.structure-desc { font-size: 13px; color: var(--color-text-muted); }
.structure-example { font-size: 12.5px; color: var(--color-text-faint); text-align: right; }

.export-card { margin-top: 24px; }
.export-card h2 { font-size: 16px; margin: 0 0 16px; }
.export-actions { display: flex; gap: 12px; flex-wrap: wrap; }
.export-note { font-size: 12px; color: var(--color-text-faint); margin: 14px 0 0; }

.tech-info { margin-top: 16px; }
.tech-info summary {
  list-style: none;
  cursor: pointer;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 10px;
  padding: 14px 18px;
  font-size: 14px;
  font-weight: 600;
  color: #334155;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.tech-info summary::-webkit-details-marker { display: none; }
.tech-info summary::after { content: "▾"; }
.tech-info[open] summary::after { content: "▴"; }
.tech-info summary:hover { background: var(--color-bg); }
.tech-info-body {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-top: none;
  border-radius: 0 0 10px 10px;
  padding: 18px;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 14px;
}
.tech-info-item p { margin: 0 0 4px; font-size: 11.5px; color: var(--color-text-muted); font-weight: 600; text-transform: uppercase; }
.tech-info-item .value { margin: 0; font-size: 13px; }
.hash { word-break: break-all; }

.preview-footer-actions { display: flex; gap: 12px; flex-wrap: wrap; justify-content: space-between; margin-top: 24px; }
.preview-footer-actions-left { display: flex; gap: 10px; flex-wrap: wrap; }

/* ---------- Methodology page ---------- */

.methodology-page {
  max-width: 1100px;
  margin: 0 auto;
  padding: 32px 24px 64px;
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 32px;
  animation: fade-in 0.3s ease-out;
}
.methodology-nav { display: flex; flex-direction: column; gap: 2px; position: sticky; top: 88px; align-self: start; }
.methodology-nav a {
  padding: 10px 14px;
  font-size: 14px;
  font-weight: 600;
  border-radius: var(--radius-md);
  color: var(--color-text-muted);
}
.methodology-nav a:hover { background: var(--color-secondary-light); }
.methodology-nav a.active { color: var(--color-primary); background: var(--color-primary-light); }

.methodology-title { display: flex; align-items: center; gap: 10px; margin-bottom: 6px; flex-wrap: wrap; }
.methodology-title h1 { margin: 0; font-size: 1.6rem; }
.methodology-definition { font-size: 15px; color: #334155; line-height: 1.65; margin: 20px 0; }
.methodology-block { padding: 18px 20px; margin-bottom: 16px; }
.methodology-block-label {
  margin: 0 0 6px;
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--color-text-muted);
  letter-spacing: 0.03em;
}
.methodology-block code { font-size: 14px; color: var(--color-text); }
.methodology-block p { margin: 0; font-size: 14px; color: #334155; line-height: 1.55; }
.methodology-reference { font-size: 12.5px; color: var(--color-text-faint); font-style: italic; margin: 0; }

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

.site-footer {
  border-top: 1px solid var(--color-border);
  background: var(--color-surface);
  margin-top: 40px;
  padding: 20px 0;
  color: var(--color-text-muted);
  font-size: 13px;
}
.footer-inner { display: flex; align-items: center; justify-content: center; gap: 16px; flex-wrap: wrap; }
.footer-sep { color: var(--color-border); }
.footer-version { color: var(--color-text-faint); }

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

@media (max-width: 900px) {
  .form-layout { grid-template-columns: 1fr; }
  .study-sidebar { position: static; }
  .methodology-page { grid-template-columns: 1fr; }
  .methodology-nav { position: static; flex-direction: row; overflow-x: auto; }
}

@media (max-width: 640px) {
  .form-row,
  .form-row-wrap { grid-template-columns: 1fr; flex-direction: column; }
  .header-inner { height: auto; padding: 12px 0; flex-wrap: wrap; gap: 10px; }
  .header-left { flex-wrap: wrap; gap: 14px; }
  h1 { font-size: 1.5rem; }
  .btn-lg { width: 100%; }
  .preview-success { flex-direction: column; align-items: flex-start; }
  .structure-row { grid-template-columns: 1fr; gap: 4px; }
  .structure-example { text-align: left; }
}