:root {
  --standard-border: 0.1em solid black;
  --base-background-color: #040C4F;
}

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
}

body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
  display: grid;
  /* header takes natural space, rest fills remaining space */
  grid-template-rows: auto 1fr;
  padding: 0 1em 1em 1em;
  height: 100vh;
}

* {
  box-sizing: border-box;
}

.page-row {
  min-height: 0;
  display: grid;
  grid-template-columns: 1fr 4fr;
  column-gap: 1em;
}

header {
  grid-column: 1 / -1;
  display: flex;
  align-items: center;
}

header h1 a, a:visited {
  text-decoration: none;
  color: CanvasText;
}

.hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

.hamburger-line {
  display: block;
  width: 100%;
  height: 2px;
  background-color: currentColor;
  transition: transform 0.25s ease, opacity 0.25s ease;
}

.page-row {
  min-height: 0;
  position: relative;
  overflow-x: hidden; /* so closed sidebar isn't shown */
}

.sidebar {
  border: var(--standard-border);
  border-radius: 0.5em;
  overflow-y: auto;
}

.sidebar ul {
  list-style-type: none;
  padding-left: 1em;
}

.sidebar ul li {
  margin-bottom: 0.5em;
}

.sidebar li ul {
  margin-top: 0.5em;
}

.overlay {
  display: none;
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.4);
  z-index: 99; /* just below the sidebar */
}

.content {
  min-height: 0;
  overflow: hidden;
  display: grid;
  grid-template-rows: 1fr;
}

.content-header {
  margin-top: 0;
}

@media (prefers-color-scheme: dark) {
  :root {
    --standard-border: 0.1em solid white;
  }

  body {
    background-color: var(--base-background-color);
  }
}

@media (max-width: 768px) {
  .page-row {
    grid-template-columns: 1fr;
  }

  .sidebar {
    position: absolute;
    top: 0;
    left: 0;
    height: 100%;
    width: 250px;
    transform: translateX(-100%);
    transition: transform 0.25s ease-in-out;
    z-index: 100;
    background-color: var(--base-background-color);
  }

  .sidebar.open {
    transform: translateX(0);
  }

  .overlay.visible {
    display: block;
  }

  .hamburger {
    display: flex;
  }
}