.site-header { display: flex; align-items: center; justify-content: space-between; gap: 1.5rem; min-height: 112px; }
.site-mark { display: inline-flex; align-items: center; gap: 16px; min-height: 64px; min-width: 44px; padding-block: 8px; font-size: 27px; line-height: 1.1; text-decoration: none; }
.mark-subtitle { display: block; font-family: var(--sans); font-size: 16px; line-height: 1.5; letter-spacing: .065em; color: var(--muted); margin-top: 5px; }
.mark-symbol { position: relative; display: block; width: 30px; height: 48px; border-left: 1px solid var(--ink); border-block: 1px solid var(--ink); }
.mark-symbol::before { content: ""; position: absolute; width: 20px; height: 38px; top: 5px; left: 5px; border-left: 1px solid var(--accent); border-block: 1px solid var(--accent); }
.mark-symbol::after { content: ""; position: absolute; width: 12px; height: 1px; top: 24px; left: 12px; background: var(--ink); }
.header-note { font-size: 17px; color: var(--muted); font-style: italic; }
.question-tabs { display: grid; grid-template-columns: repeat(5, minmax(0, 1fr)); border-bottom: 1px solid var(--ink); gap: 6px; padding-top: 8px; }
.question-tab {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 56px;
  min-width: 44px;
  padding: .75rem .6rem;
  border: 1px solid var(--rule);
  border-bottom: 0;
  color: var(--ink);
  font-size: 17px;
  line-height: 1.35;
  text-align: center;
  text-decoration: none;
}
.question-tab[aria-current] { background: var(--ink); border-color: var(--ink); color: var(--sheet); }
.question-tab:hover { background: var(--sheet); border-color: var(--ink); color: var(--ink); }
.site-footer { padding-block: 2rem 2.5rem; margin-top: 3rem; border-top: 1px solid var(--ink); }
.site-footer > p { max-width: 65ch; font-size: 17px; }
.site-footer nav { display: flex; flex-wrap: wrap; gap: .3rem 1.6rem; margin-top: 1.15rem; }
.site-footer a { font-family: var(--sans); min-height: 48px; font-size: 16px; }
@media (max-width: 900px) {
  .question-tab { font-size: 16px; }
}
@media (max-width: 650px) {
  .site-header { min-height: 96px; }
  .header-note { display: none; }
  .site-mark { font-size: 25px; }
  .question-tabs { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 6px; padding-bottom: 8px; border-bottom: 1px solid var(--ink); }
  .question-tab { min-height: 48px; border-bottom: 1px solid var(--rule); padding: .65rem .5rem; }
  .question-tab:last-child { grid-column: 1 / -1; }
  .site-footer { margin-top: 2rem; padding-block: 1.6rem 2rem; }
  .site-footer nav { gap: .25rem 1.1rem; }
}