:root {
  --bg: #08111f;
  --bg-2: #0c1731;
  --bg-strong: #0d1a34;
  --surface: rgba(255, 255, 255, 0.82);
  --surface-strong: rgba(12, 22, 40, 0.88);
  --panel-soft: rgba(255, 255, 255, 0.84);
  --line: rgba(10, 24, 46, 0.1);
  --text: #102035;
  --muted: #5a6d87;
  --text-soft: #5a6d87;
  --white: #f7f9fd;
  --text-inverse: #f7f9fd;
  --blue: #008bf7;
  --accent: #c833b6;
  --accent-dark: #a52ca0;
  --success-bg: #dff2e4;
  --success-text: #1d7a47;
  --warning-bg: #f8edd4;
  --warning-text: #87611a;
  --info-bg: #deebfb;
  --info-text: #2858b8;
  --shadow: 0 32px 90px rgba(0, 0, 0, 0.18);
  --radius-xl: 28px;
  --radius-lg: 22px;
  --radius-md: 16px;
  --sidebar: 290px;
  --sidebar-width: 290px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: "Avenir Next", "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  color: var(--text);
  line-height: 1.6;
  background: linear-gradient(180deg, #eef4fb 0%, #f8fbff 42%, #edf2f8 100%);
}

a {
  color: inherit;
  text-decoration: none;
}

.layout {
  display: grid;
  grid-template-columns: var(--sidebar) minmax(0, 1fr);
  min-height: 100vh;
}

.sidebar {
  position: sticky;
  top: 0;
  height: 100vh;
  padding: 24px 18px;
  overflow: auto;
  background: linear-gradient(180deg, #09111f 0%, #0d1a34 100%);
  color: var(--white);
  border-right: 1px solid rgba(255, 255, 255, 0.08);
}

.sidebar-top {
  display: flex;
  margin-bottom: 18px;
}

.xebia-logo {
  display: block;
  width: 108px;
}

.xebia-logo svg {
  width: 50%;
  height: auto;
  display: block;
}

.brand {
  display: flex;
  align-items: flex-start;
  margin-bottom: 18px;
}

.brand strong,
.hero h1,
h2,
h3,
.stage-number {
  font-family: "Poppins", "Avenir Next", "Segoe UI", sans-serif;
  letter-spacing: -0.03em;
}

.brand strong {
  display: block;
  font-size: 1rem;
}

.brand span {
  display: block;
  color: rgba(247, 249, 253, 0.68);
  font-size: 0.76rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.nav-label,
.sidebar h2 {
  margin: 0 0 12px;
  font-size: 0.8rem;
  color: rgba(247, 249, 253, 0.62);
  text-transform: uppercase;
  letter-spacing: 0.18em;
}

.toc {
  display: grid;
  gap: 8px;
}

.toc a {
  display: block;
  padding: 10px 12px;
  border-radius: 12px;
  color: rgba(247, 249, 253, 0.82);
  transition: 0.18s ease;
  font-size: 0.95rem;
  line-height: 1.35;
}

.toc a:hover,
.toc a.is-active {
  background: rgba(255, 255, 255, 0.08);
  text-decoration: none;
}

.main {
  min-width: 0;
}

.mobile-topbar {
  display: none;
  position: sticky;
  top: 0;
  z-index: 40;
  padding: 14px 18px;
  backdrop-filter: blur(16px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  justify-content: space-between;
  align-items: center;
}

@media (max-width: 1100px) {
  .layout {
    grid-template-columns: 1fr;
  }

  .sidebar {
    display: none;
  }

  .mobile-topbar {
    display: flex;
  }
}