:root {
  color-scheme: light;
  --background: #f7f7f7;
  --header: #ededed;
  --text: #393e46;
  --border: #c5c9d1;
  --control: #eeeeee;
  --control-hover: #e5e7eb;
}
:root[data-theme="dark"] {
  color-scheme: dark;
  --background: #171717;
  --header: #111111;
  --text: #efefeb;
  --border: #4c4c48;
  --control: #222222;
  --control-hover: #303030;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) {
    color-scheme: dark;
    --background: #171717;
    --header: #111111;
    --text: #efefeb;
    --border: #4c4c48;
    --control: #222222;
    --control-hover: #303030;
  }
  :root:not([data-theme]) .logo-light { display: none; }
  :root:not([data-theme]) .logo-dark { display: block; }
}
* { box-sizing: border-box; }
body { margin: 0; min-height: 100svh; background: var(--background); color: var(--text); font-family: Arial, Helvetica, sans-serif; -webkit-font-smoothing: antialiased; }
.masthead { min-height: 72px; padding: 10px 24px; display: flex; align-items: center; justify-content: space-between; gap: 24px; background: var(--header); border-bottom: 1px solid var(--border); }
.brand { width: 260px; max-width: calc(100% - 56px); flex: 0 1 auto; display: block; }
.brand img { width: 100%; height: auto; display: block; }
.brand .logo-dark { display: none; }
:root[data-theme="dark"] .logo-light { display: none; }
:root[data-theme="dark"] .logo-dark { display: block; }
#theme-toggle { position: relative; touch-action: manipulation; flex: 0 0 32px; width: 32px; height: 32px; padding: 7px; border: 1px solid var(--border); border-radius: 7px; background: var(--control); color: var(--text); cursor: pointer; }

#theme-toggle::after { content: ""; position: absolute; width: 44px; height: 44px; top: 50%; left: 50%; transform: translate(-50%, -50%); }
#theme-toggle[hidden] { display: none; }
#theme-toggle:hover { background: var(--control-hover); }
#theme-toggle svg { display: block; width: 16px; height: 16px; fill: none; stroke: currentColor; stroke-width: 1.6; stroke-linecap: round; stroke-linejoin: round; }
#theme-toggle .sun { display: none; }
:root[data-theme="dark"] #theme-toggle .moon { display: none; }
:root[data-theme="dark"] #theme-toggle .sun { display: block; }
:focus-visible { outline: 2px solid currentColor; outline-offset: 5px; }
main { max-width: 860px; margin: 0 auto; padding: clamp(80px, 15vh, 160px) 40px 100px; }
main:focus { outline: none; }
.introduction { font-size: 16px; line-height: 1.7; font-weight: 400; }
p { margin: 0 0 1.5em; }
p:last-child { margin-bottom: 0; }
.visually-hidden { position: absolute; width: 1px; height: 1px; margin: -1px; padding: 0; overflow: hidden; clip-path: inset(50%); white-space: nowrap; border: 0; }
.skip-link { position: absolute; z-index: 1; top: 8px; left: 16px; transform: translateY(-160%); padding: 10px 14px; background: var(--background); color: var(--text); }
.skip-link:focus { transform: translateY(0); }
@media (max-width: 600px) {
  .masthead { min-height: 66px; padding: 10px 18px; gap: 12px; }
  .brand { width: 220px; max-width: calc(100% - 44px); }
  main { padding: 64px 26px 72px; }
  .introduction { font-size: 15px; line-height: 1.75; }
}
@media print {
  body { color: #111; background: white; }
  .masthead { background: white; border-color: #bbb; }
  .brand .logo-light { display: block !important; }
  .brand .logo-dark, #theme-toggle, .skip-link { display: none !important; }
  main { padding-top: 60px; }
}