:root {
  --usbr-spillway-blue: #0081a1;
  --usbr-spillway-blue-dark: #00566b;
  --usbr-spillway-blue-light: #d4eaef;
  --usbr-banner-blue: #1e3780;
  --usbr-banner-blue-deep: #123764;
  --usbr-banner-teal: #043649;
  --usbr-red-rocks: #a23737;
  --usbr-canyon-gold: #c2850c;
  --usbr-warning: #fff5ee;
  --ink: #202124;
  --muted: #59636a;
  --paper: #ffffff;
  --wash: #f4f8fa;
  --line: #d7e4e8;
  --code-bg: #10242b;
  --radius: 14px;
  --shadow: 0 18px 45px rgba(0, 64, 80, 0.16);
  --content-width: 78rem;
}

* {
  box-sizing: border-box;
}

html {
  color: var(--ink);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 16px;
  line-height: 1.55;
  background: var(--wash);
}

body {
  margin: 0;
}

a {
  color: var(--usbr-spillway-blue-dark);
  text-decoration-thickness: 0.08em;
  text-underline-offset: 0.18em;
}

a:hover {
  color: var(--usbr-red-rocks);
}

.site-header {
  color: #fff;
  background-color: var(--usbr-banner-teal);
  background-image: linear-gradient(
    180deg,
    var(--usbr-banner-blue) 0%,
    var(--usbr-banner-blue-deep) 52%,
    var(--usbr-banner-teal) 100%
  );
}

.brand-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 1rem 1.5rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.9rem;
  color: #fff;
  text-decoration: none;
}

.brand-logo {
  width: clamp(13rem, 25vw, 19rem);
  height: auto;
  object-fit: contain;
}

.brand strong,
.brand small {
  display: block;
}

.brand small {
  color: rgba(255, 255, 255, 0.82);
  font-size: 0.85rem;
  letter-spacing: 0.02em;
}

.site-nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 0.45rem;
}

.site-nav a {
  color: #fff;
  border-radius: 4px;
  padding: 0.4rem 0.5rem;
  font-weight: 700;
  text-decoration: none;
}

.site-nav a:hover {
  background: rgba(255, 255, 255, 0.13);
}

.site-nav a:focus-visible {
  outline: 2px solid #fff;
  outline-offset: 3px;
}

.hero {
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 4.5rem 1.5rem 5rem;
}

.eyebrow {
  color: rgba(255, 255, 255, 0.82);
  font-weight: 700;
  letter-spacing: 0.1em;
  margin: 0 0 0.8rem;
  text-transform: uppercase;
}

.hero h1 {
  max-width: 58rem;
  margin: 0;
  color: #fff;
  font-size: clamp(2.45rem, 6vw, 5.2rem);
  line-height: 0.98;
  letter-spacing: -0.05em;
}

.lede {
  max-width: 44rem;
  margin: 1.2rem 0 0;
  color: rgba(255, 255, 255, 0.88);
  font-size: clamp(1.05rem, 2vw, 1.32rem);
}

.page-shell {
  display: grid;
  grid-template-columns: 16rem minmax(0, 1fr);
  gap: 2rem;
  max-width: var(--content-width);
  margin: -2.25rem auto 0;
  padding: 0 1.5rem 4rem;
}

.sidebar {
  align-self: start;
  position: sticky;
  top: 1rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1rem;
  background: var(--paper);
  box-shadow: var(--shadow);
}

.sidebar a {
  display: block;
  border-radius: 10px;
  padding: 0.45rem 0.55rem;
  text-decoration: none;
}

.sidebar a:hover {
  background: var(--usbr-spillway-blue-light);
}

.sidebar-title {
  margin: 1rem 0 0.35rem;
  color: var(--muted);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.sidebar-title:first-child {
  margin-top: 0;
}

.content {
  min-width: 0;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: clamp(1.3rem, 4vw, 3rem);
  background: var(--paper);
  box-shadow: var(--shadow);
}

.content > h1:first-child {
  margin-top: 0;
}

h1,
h2,
h3,
h4 {
  color: #163b46;
  line-height: 1.16;
}

h2 {
  margin-top: 2.6rem;
  padding-top: 0.8rem;
  border-top: 3px solid var(--usbr-spillway-blue-light);
}

h3 {
  margin-top: 2rem;
}

p,
ul,
ol,
table,
pre,
blockquote {
  margin-top: 1rem;
  margin-bottom: 1rem;
}

blockquote {
  border-left: 4px solid var(--usbr-canyon-gold);
  margin-left: 0;
  padding: 0.2rem 0 0.2rem 1rem;
  color: var(--muted);
}

code {
  border-radius: 6px;
  padding: 0.1rem 0.25rem;
  color: #0a3945;
  background: var(--usbr-spillway-blue-light);
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.92em;
}

pre {
  overflow-x: auto;
  border-radius: 12px;
  padding: 1rem;
  color: #edf8fb;
  background: var(--code-bg);
}

pre code {
  padding: 0;
  color: inherit;
  background: transparent;
}

table {
  display: block;
  width: 100%;
  overflow-x: auto;
  border-collapse: collapse;
}

th,
td {
  border: 1px solid var(--line);
  padding: 0.55rem 0.7rem;
  vertical-align: top;
}

th {
  color: #fff;
  background: var(--usbr-spillway-blue-dark);
}

tr:nth-child(even) td {
  background: #f8fbfc;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1rem;
  margin: 1.5rem 0;
}

.card {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.2rem;
  background: #fbfdfe;
}

.card h2,
.card h3 {
  border: 0;
  margin-top: 0;
  padding-top: 0;
}

.button-link {
  display: inline-flex;
  align-items: center;
  border-radius: 999px;
  padding: 0.6rem 0.9rem;
  color: #fff;
  background: var(--usbr-spillway-blue);
  text-decoration: none;
}

.button-link:hover {
  color: #fff;
  background: var(--usbr-red-rocks);
}

.example-tabs {
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 8px;
  margin: 1.25rem 0 1.6rem;
  background: #fbfdfe;
}

.tab-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  border-bottom: 1px solid var(--line);
  padding: 0.55rem;
  background: var(--wash);
}

.tab-button {
  border: 1px solid transparent;
  border-radius: 6px;
  padding: 0.42rem 0.65rem;
  color: #163b46;
  background: transparent;
  font: inherit;
  font-weight: 700;
  cursor: pointer;
}

.tab-button:hover {
  border-color: var(--line);
  background: #fff;
}

.tab-button:focus-visible {
  outline: 2px solid var(--usbr-banner-blue);
  outline-offset: 2px;
}

.tab-button[aria-selected="true"] {
  color: #fff;
  background: var(--usbr-banner-blue-deep);
}

.tab-panel {
  padding: 0.2rem 1rem 1rem;
}

.tab-panel[hidden] {
  display: none;
}

.tab-panel pre:last-child,
.tab-panel p:last-child {
  margin-bottom: 0;
}

.site-footer {
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 0 1.5rem 2rem;
  color: var(--muted);
  font-size: 0.92rem;
}

@media (max-width: 900px) {
  .brand-bar,
  .page-shell {
    display: block;
  }

  .site-nav {
    justify-content: flex-start;
    margin-top: 1rem;
  }

  .page-shell {
    margin-top: -1rem;
  }

  .sidebar {
    position: static;
    margin-bottom: 1rem;
  }

  .card-grid {
    grid-template-columns: 1fr;
  }
}