:root {
  --bg: #0f111a;
  --surface: #181818;
  --surface-alt: #1e1e1e;
  --border: #2a3040;
  --text: #cccccc;
  --muted: #9aa4b5;
  --accent: #258443;
  --header-height: 92px;
}

/* *,
*::before,
*::after {
  /* box-sizing: border-box; 
} */

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Inter", "Segoe UI", system-ui, -apple-system, sans-serif;
  background: #181818;
  color: var(--text);
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: flex-start;
  gap: 1.25rem;
  padding: 1rem clamp(1.25rem, 4vw, 3rem);
  /*background: rgba(15, 17, 26, 0.92);*/
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(18px);
}

.brand-logo {
  height: 56px;
  width: auto;
  display: block;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  border-radius: 16px;
  background: linear-gradient(135deg, #ef9f63, #64e8a0);
  font-weight: 700;
  letter-spacing: 0.05em;
}

.brand-copy {
  display: flex;
  flex-direction: column;
  line-height: 1.1;
}

.brand-title {
  text-transform: uppercase;
  font-weight: 600;
  letter-spacing: 0.08em;
  font-size: 0.85rem;
}

.brand-tagline {
  font-size: 0.75rem;
  color: var(--muted);
}

.top-menu {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.top-link {
  border: 1px solid transparent;
  background: transparent;
  color: var(--text);
  font-size: 0.95rem;
  padding: 0.4rem 1.1rem;
  border-radius: 999px;
  cursor: pointer;
  transition: border-color 0.2s ease, background 0.2s ease, color 0.2s ease;
}

.top-link:hover {
  border-color: rgba(42, 142, 242, 0.6);
}

.top-link.is-active {
  background: #04395E;
  color: var(--text);
  border-color: transparent;
}

.layout {
  display: flex;
  min-height: calc(100vh - var(--header-height));
}

.sidebar {
  width: 260px;
  padding: 1.5rem;
  background: var(--surface);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  overflow-y: auto;
  position: sticky;
  top: var(--header-height);
  align-self: flex-start;
  max-height: calc(100vh - var(--header-height));
}

.nav-tree {
  width: 100%;
  font-size: 0.95rem;
}

.tree-level {
  list-style: none;
  margin: 0;
  padding-left: 0;
}

.tree-item {
  --depth: 0;
}

.tree-row {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.15rem 0.35rem;
  padding-left: calc(0.35rem + var(--depth) * 1rem);
  border-radius: 6px;
  transition: background 0.2s ease;
}

.tree-item:hover > .tree-row {
  background: rgba(69, 131, 212, 0.1);
}

.tree-toggle {
  width: 1.1rem;
  height: 1.1rem;
  border: none;
  background: transparent;
  padding: 0;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
}

.tree-toggle::before {
  content: "";
  border-style: solid;
  border-width: 0.3rem 0 0.3rem 0.45rem;
  border-color: transparent transparent transparent var(--muted);
  display: inline-block;
  transform-origin: center;
  transform: rotate(90deg);
  transition: transform 0.15s ease;
}

.tree-toggle.placeholder {
  visibility: hidden;
}

.tree-item.is-collapsed > .tree-row .tree-toggle::before {
  transform: rotate(0deg);
}

.tree-label {
  flex: 1;
  text-align: left;
  border: none;
  background: transparent;
  color: inherit;
  font: inherit;
  padding: 0.2rem 0.25rem;
  border-radius: 4px;
  cursor: pointer;
}

.tree-label.is-disabled {
  color: var(--muted);
  cursor: not-allowed;
  opacity: 0.7;
  pointer-events: none;
}

.tree-label--static {
  cursor: default;
  color: var(--muted);
}

.tree-label.is-active {
  color: #ffffff;
  background: #044252;
}

.tree-children {
  margin: 0;
  padding-left: 0;
}

.tree-item.is-collapsed > .tree-children {
  display: none;
}

[data-tree-collapsible="true"] {
  --fold-toggle-size: 1.1rem;
  --fold-toggle-color: currentColor;
}

[data-tree-collapsible="true"] ul {
  list-style: none;
  padding-left: 0.6rem;
  margin: 0.2rem 0;
}

[data-tree-collapsible="true"] li {
  position: relative;
  padding-left: calc(var(--fold-toggle-size) - 0.6rem);
}

[data-tree-collapsible="true"] li.has-fold-toggle {
  cursor: default;
}

.fold-toggle {
  position: absolute;
  left: -0.3rem;
  top: 0rem;
  /*width: var(--fold-toggle-size);*/
  height: var(--fold-toggle-size);
  border: none;
  background: none;
  padding: 0;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: inherit;
  cursor: pointer;
}

.fold-toggle::before {
  content: "";
  border-style: solid;
  border-width: 0.3rem 0 0.3rem 0.45rem;
  border-color: transparent transparent transparent var(--fold-toggle-color);
  transform-origin: center;
  transform: rotate(90deg);
  transition: transform 0.15s ease;
}

.fold-toggle[aria-expanded="false"]::before {
  transform: rotate(0deg);
}

.fold-toggle:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.content {
  flex: 1;
  padding: clamp(1.5rem, 4vw, 4rem);
  background: var(--surface-alt);
}

/* #content {
  max-width: 760px;
} */

#content h1 {
  margin-top: 0;
  font-size: clamp(1.8rem, 3.8vw, 2.6rem);
}

#content p {
  line-height: 1.7;
  color: #d7ddeb;
}

#content ul {
  padding-left: 1.2rem;
  /* color: #e0e6f8; */
}

.info-tag {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.85rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 1rem;
}

.info-tag::before {
  content: "";
  width: 28px;
  height: 1px;
  background: var(--border);
  display: inline-block;
}

@media (max-width: 960px) {
  .layout {
    flex-direction: column;
  }

  .sidebar {
    width: 100%;
    flex-direction: column;
    position: static;
    top: auto;
    max-height: none;
  }
}

@media (max-width: 640px) {
  .site-header {
    flex-direction: column;
    align-items: flex-start;
  }

  .top-menu {
    width: 100%;
  }

  .sidebar {
    padding: 1rem;
  }
}