:root {
  --bg-main: #020617;        /* very dark slate */
  --bg-card: #020617;
  --bg-card-elevated: #020617;
  --bg-page: radial-gradient(circle at top, #0f172a 0%, #020617 55%, #000 100%);
  --border-subtle: #1f2937;
  --accent: #38bdf8;
  --accent-soft: rgba(56, 189, 248, 0.12);
  --accent-strong: #0ea5e9;
  --text-main: #e5e7eb;
  --text-muted: #9ca3af;
  --text-soft: #6b7280;
  --text-strong: #f9fafb;
  --danger: #f97373;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --shadow-soft: 0 18px 45px rgba(15, 23, 42, 0.85);
  --shadow-subtle: 0 8px 25px rgba(15, 23, 42, 0.65);
  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

*,
*::before,
*::after {
  box-sizing: content-box;
}

html,
body {
  margin: 0;
  padding: 0;
}

body {
  min-height: 100vh;
  font-family: var(--font-sans);
  background: var(--bg-page);
  color: var(--text-main);
  -webkit-font-smoothing: antialiased;
}

/* Layout */

.page {
  max-width: 1100px;
  margin: 0 auto;
  padding: 32px 20px 64px;
}

@media (min-width: 768px) {
  .page {
    padding: 40px 24px 80px;
  }
}

/* Header */

.page-header {
  padding: 24px 20px 28px;
  border-radius: 24px;
  background: radial-gradient(circle at top left, rgba(56, 189, 248, 0.12), transparent 60%),
              radial-gradient(circle at top right, rgba(129, 140, 248, 0.12), transparent 55%),
              rgba(15, 23, 42, 0.9);
  box-shadow: var(--shadow-soft);
  border: 1px solid rgba(148, 163, 184, 0.25);
  backdrop-filter: blur(18px);
}

.page-header h1 {
  margin: 6px 0 6px;
  font-size: clamp(1.9rem, 4vw, 2.4rem);
  letter-spacing: 0.03em;
  color: var(--text-strong);
}

.page-header .subtitle {
  margin: 0;
  font-size: 0.95rem;
  color: var(--accent);
}

.page-header .meta {
  margin-top: 8px;
  font-size: 0.85rem;
  color: var(--text-soft);
}

.page-header .motto {
  margin-top: 16px;
  font-size: 0.95rem;
  color: var(--text-main);
  border-left: 3px solid var(--accent);
  padding-left: 12px;
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 2px 10px 3px;
  border-radius: 999px;
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent-strong);
  background: rgba(15, 23, 42, 0.7);
  border: 1px solid rgba(56, 189, 248, 0.35);
}

/* TOC */

.toc {
  margin-top: 24px;
  margin-bottom: 24px;
  padding: 18px 18px 16px;
  border-radius: 18px;
  background: rgba(15, 23, 42, 0.9);
  border: 1px solid rgba(55, 65, 81, 0.9);
  box-shadow: var(--shadow-subtle);
}

.toc h2 {
  margin: 0 0 10px;
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--text-soft);
}

.toc ul {
  list-style: none;
  padding-left: 0;
  margin: 0;
  display: grid;
  gap: 6px;
}

.toc li {
  font-size: 0.9rem;
}

.toc a {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
  color: var(--text-main);
  padding: 5px 8px;
  border-radius: 10px;
  transition: background 0.16s ease, color 0.16s ease, transform 0.08s ease;
}

.toc a::before {
  content: "●";
  font-size: 0.55rem;
  color: var(--accent);
}

.toc a:hover {
  background: var(--accent-soft);
  color: var(--accent-strong);
  transform: translateY(-1px);
}

/* Cards (Sections) */

.card {
  margin-top: 22px;
  padding: 20px 20px 22px;
  border-radius: var(--radius-xl);
  background: linear-gradient(135deg, rgba(15, 23, 42, 0.96), rgba(15, 23, 42, 0.98));
  border: 1px solid var(--border-subtle);
  box-shadow: var(--shadow-subtle);
}

.section-intro {
  margin-top: 24px;
}

.card h2 {
  margin-top: 0;
  margin-bottom: 12px;
  font-size: 1.25rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--accent-strong);
}

.card h3 {
  margin-top: 14px;
  margin-bottom: 4px;
  font-size: 1.05rem;
  color: var(--text-strong);
}

.card h4 {
  margin-top: 12px;
  margin-bottom: 4px;
  font-size: 0.95rem;
  color: var(--text-main);
}

.card p {
  margin: 6px 0;
  font-size: 0.93rem;
  line-height: 1.6;
  color: var(--text-main);
}

.card em {
  color: var(--text-soft);
}

/* Lists */

.card ul,
.card ol {
  margin: 6px 0 8px;
  padding-left: 18px;
  font-size: 0.93rem;
}

.card li {
  margin-bottom: 4px;
}

.card li strong {
  color: var(--accent-strong);
}

/* Table-like blocks */

.table {
  width: 100%;
  border-radius: 12px;
  border: 1px solid var(--border-subtle);
  overflow: hidden;
  margin: 10px 0 14px;
  font-size: 0.9rem;
}

.table-row {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  padding: 8px 10px;
  gap: 10px;
}

.table-row div {
  min-width: 0;
}

.table-header {
  background: rgba(15, 23, 42, 0.98);
  font-weight: 600;
  color: var(--text-soft);
  border-bottom: 1px solid var(--border-subtle);
}

.table-row:not(.table-header):nth-child(even) {
  background: rgba(15, 23, 42, 0.86);
}

.table-row:not(.table-header):nth-child(odd) {
  background: rgba(15, 23, 42, 0.96);
}

@media (max-width: 720px) {
  .table-row {
    grid-template-columns: 1.1fr 1.1fr;
  }
  .table-row.table-header {
    grid-template-columns: 1.1fr 1.1fr;
  }
}

/* Code blocks */

.code-block {
  margin: 10px 0 14px;
  padding: 10px 12px;
  border-radius: 12px;
  background: #020617;
  border: 1px solid rgba(31, 41, 55, 0.85);
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono",
    "Courier New", monospace;
  font-size: 0.86rem;
  white-space: pre-wrap;
  word-wrap: break-word;
}

code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono",
    "Courier New", monospace;
  font-size: 0.85rem;
  padding: 1px 4px;
  border-radius: 6px;
  background: rgba(15, 23, 42, 0.95);
  border: 1px solid rgba(31, 41, 55, 0.9);
}

/* Back to top */

.back-to-top {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: 10px;
  font-size: 0.85rem;
  color: var(--text-soft);
  text-decoration: none;
  padding: 4px 8px;
  border-radius: 999px;
  background: rgba(15, 23, 42, 0.95);
  border: 1px solid rgba(31, 41, 55, 0.8);
  transition: background 0.18s ease, color 0.18s ease, transform 0.08s ease;
}

.back-to-top::before {
  content: "↑";
  font-size: 0.8rem;
}

.back-to-top:hover {
  background: var(--accent-soft);
  color: var(--accent-strong);
  transform: translateY(-1px);
}

/* Footer */

.page-footer {
  margin-top: 32px;
  text-align: center;
  font-size: 0.82rem;
  color: var(--text-soft);
  opacity: 0.8;
}
/* ===== Global smooth scroll & spacing for fixed nav ===== */
html {
  scroll-behavior: smooth;
}

body {
  padding-top: 80px; 
}

/* ===== Top fixed navbar ===== */
.top-nav {
  position: fixed;
  inset-inline: 0;
  top: 0;
  z-index: 40;
  backdrop-filter: blur(18px);
  background: radial-gradient(circle at top left, rgba(67, 149, 255, 0.18), transparent 55%),
              rgba(3, 9, 23, 0.96);
  border-bottom: 1px solid rgba(148, 163, 184, 0.16);
}

.nav-inner {
  max-width: 1120px;
  margin: 0 auto;
  padding: 10px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.nav-left {
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: 0;
}

.nav-logo {
  width: 100px;
  height: 40px;
  object-fit: contain;
  border-radius: 8px;
  box-shadow: 0 10px 30px rgba(15, 23, 42, 0.7);
  background: radial-gradient(circle at 30% 0%, rgba(56, 189, 248, 0.3), transparent 55%),
              #020617;
}

.nav-title-group {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.nav-title-main {
  font-size: 0.95rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: #e5f0ff;
}

.nav-title-sub {
  font-size: 0.75rem;
  color: #9ca3af;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 14px;
  font-size: 0.82rem;
}

.nav-links a {
  position: relative;
  text-decoration: none;
  color: #cbd5f5;
  padding: 6px 10px;
  border-radius: 999px;
  border: 1px solid transparent;
  opacity: 0.86;
  transition: all 0.18s ease-out;
}

.nav-links a::after {
  content: "";
  position: absolute;
  inset-inline: 12%;
  bottom: 4px;
  height: 2px;
  border-radius: 999px;
  background: linear-gradient(90deg, #22d3ee, #60a5fa);
  opacity: 0;
  transform: scaleX(0.4);
  transform-origin: center;
  transition: all 0.18s ease-out;
}

.nav-links a:hover {
  opacity: 1;
  border-color: rgba(148, 163, 184, 0.4);
  background: radial-gradient(circle at top, rgba(59, 130, 246, 0.15), transparent 60%);
}

.nav-links a:hover::after {
  opacity: 1;
  transform: scaleX(1);
}

@media (max-width: 768px) {
  .nav-inner {
    padding-inline: 16px;
    gap: 12px;
  }

  

  .nav-links {
    display: none; 
  }

  @media (max-width: 1200px) {
  .nav-links a {
    font-size: 0.85rem;
    padding: 0 8px;
  }
}


  body {
    padding-top: 70px;
  }
}

/* ===== Anchor highlight (section focus) ===== */

section[id] {
  scroll-margin-top: 96px;
}

:target {
  animation: anchorHighlight 0.9s ease-out;
  position: relative;
}

:target::before {
  content: "";
  position: absolute;
  inset: -8px -10px;
  border-radius: 24px;
  background:
    radial-gradient(circle at top left, rgba(56, 189, 248, 0.18), transparent 60%),
    rgba(15, 23, 42, 0.8);
  box-shadow:
    0 0 0 1px rgba(148, 163, 184, 0.28),
    0 22px 60px rgba(15, 23, 42, 0.85);
  z-index: -1;
}

@keyframes anchorHighlight {
  0% {
    transform: translateY(2px);
    opacity: 0.3;
  }
  40% {
    transform: translateY(0);
    opacity: 1;
  }
  100% {
    transform: translateY(0);
    opacity: 1;
  }
}