:root {
  --navy: #001f3f;
  --navy-mid: #003366;
  --ink: #111111;
  --paper: #ffffff;
  --accent: #4da3ff;
  --sidebar: 15rem;
}

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html,
body {
  font-size: calc(1em + 0.28vw);
  font-family: Arial, Helvetica, sans-serif;
  line-height: 1.5;
  color: var(--ink);
  background: var(--paper);
}

html.dark,
html.dark body,
body.dark {
  --ink: #ffffff;
  --paper: #001f3f;
  --navy: #001f3f;
  --accent: #8ec8ff;
}

a { color: inherit; text-decoration: none; border-bottom: 1px solid currentColor; }
img { max-width: 100%; height: auto; }
.vh { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); }

[href="#main"] {
  position: fixed;
  top: -3rem;
  left: 0;
  right: 0;
  background: var(--navy);
  color: #fff;
  padding: 0.75rem;
  text-align: center;
  z-index: 40;
}
[href="#main"]:focus { top: 0; }

.wrapper { overflow-x: hidden; }

.top-edge {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  z-index: 30;
  pointer-events: none;
  background: linear-gradient(
    to right,
    var(--navy) 0,
    var(--navy) var(--sidebar),
    #fff var(--sidebar),
    #fff 100%
  );
}
html.dark .top-edge,
body.dark .top-edge {
  background: var(--navy);
}

html.dark .intro-and-nav,
body.dark .intro-and-nav {
  border-right-color: rgba(255, 255, 255, 0.35);
}
.intro-and-nav {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--sidebar);
  height: 100vh;
  background: var(--navy);
  color: #fff;
  border-right: 2px solid #000;
  font-size: 0.8rem;
  overflow: hidden;
  z-index: 20;
}
.intro-and-nav > div {
  display: flex;
  flex-direction: column;
  height: 100%;
  min-height: 0;
  padding: 1.5rem 1.15rem 1rem;
}
.intro {
  flex: 0 0 auto;
  position: sticky;
  top: 0;
  z-index: 2;
  background: var(--navy);
  padding-bottom: 0.65rem;
  border-bottom: 2px solid #fff;
}
.logo { border: 0; display: block; }
.logo img {
  width: 100%;
  max-width: 10.5rem;
  background: transparent;
}
.library-desc {
  margin-top: 0.5rem;
  text-align: center;
  font-weight: bold;
}
.library-desc a {
  border: 0;
  color: inherit;
}

.patterns {
  margin-top: 0.9rem;
  overflow: auto;
  flex: 1 1 auto;
  min-height: 0;
}
.patterns ul { list-style: none; }
.patterns li + li { margin-top: 0.45rem; }
.pattern a {
  border: 0;
  display: flex;
  align-items: center;
  gap: 0.3rem;
  font-weight: bold;
  line-height: 1.15;
  padding: 0.12rem 0.55rem;
}
.pattern [aria-current] {
  background: #fff;
  color: var(--navy);
  clip-path: polygon(0% 0%, 92% 0%, 100% 50%, 92% 100%, 0% 100%);
  padding-top: 0.22em;
  padding-bottom: 0.22em;
}
.icon { width: 0.5rem; height: 0.65rem; fill: none; stroke: currentColor; stroke-width: 3.2; }

#menu-button {
  display: none;
  width: 100%;
  background: #fff;
  color: var(--navy);
  border: 0;
  font: inherit;
  font-weight: bold;
  padding: 0.6rem;
  border-radius: 0.3rem;
}

.main-and-footer { margin-left: var(--sidebar); }
.main-and-footer > div {
  max-width: 48rem;
  margin: 0 auto;
  padding: 2.25rem 1.5rem 3rem;
}
h1, h2, h3 { line-height: 1.15; font-weight: bold; }
h1 { font-size: 2rem; margin-bottom: 1rem; }
h2 { font-size: 1.35rem; margin: 1.75rem 0 0.75rem; }
p + p { margin-top: 0.75rem; }
main ul { margin: 0.75rem 0 0 1.5rem; }
main li + li { margin-top: 0.4rem; }

.shot {
  margin: 1.5rem 0 1.75rem;
}
.shot img {
  display: block;
  width: 100%;
  border: 1px solid currentColor;
}
.shot figcaption {
  margin-top: 0.45rem;
  font-size: 0.9rem;
  text-align: center;
}

.amounts { margin-top: 1rem; }
.amounts .btn { min-width: 4.5rem; text-align: center; }

.btn {
  display: inline-block;
  border: 0;
  background: var(--navy);
  color: #fff;
  font-weight: bold;
  padding: 0.65rem 1.1rem;
  border-radius: 0.3rem;
  margin: 0.35rem 0.4rem 0.35rem 0;
}
body.dark .btn { background: #fff; color: #001f3f; }
.btn.secondary { background: transparent; color: inherit; border: 2px solid var(--navy); }
html.dark .btn.secondary,
body.dark .btn.secondary { border-color: #fff; }

.cards { display: grid; gap: 0.85rem; margin-top: 1rem; }
.card {
  border: 2px solid currentColor;
  padding: 1rem 1.1rem;
}
.card h2 { margin-top: 0; font-size: 1.1rem; }

footer {
  margin-top: 3.5rem;
  text-align: center;
  font-size: 0.85rem;
}
footer .theme-toggle {
  display: block;
  margin: 0 0 2.25rem;
}
footer .copy {
  display: block;
  margin: 0;
  padding-top: 0.25rem;
}
[for="themer"] {
  display: inline-block;
  background: var(--navy);
  color: #fff;
  padding: 0.25rem 0.75rem;
  border-radius: 0.3rem;
  cursor: pointer;
}
html.dark [for="themer"],
body.dark [for="themer"] {
  background: #fff;
  color: #001f3f;
}
[for="themer"] [aria-hidden]::before { content: "off"; }
[for="themer"] :checked + [aria-hidden]::before { content: "on"; }

@media (max-width: 52rem) {
  .intro-and-nav {
    position: sticky;
    top: 0;
    width: 100%;
    height: auto;
    max-height: 100vh;
  }
  .main-and-footer { margin-left: 0; }
  #menu-button { display: block; margin-bottom: 0.75rem; }
  #patterns-list { display: none; }
  #patterns-list.open { display: block; }
}