/* ==========================================================================
   Masthead: brand row (monogram + title + meta) and the month-runway hero -
   two mono tiles + accent arrow, the page's signature moment.
   ========================================================================== */

.masthead {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  padding: var(--space-4);
  background: var(--surface-panel);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-card);
  /* Top hairline highlight: panels read as milled metal, not floating cards. */
  box-shadow: inset 0 1px 0 var(--surface-edge);
  animation: rise-in var(--dur-emphasis) var(--ease-emphasis) both;
}

@media (min-width: 768px) {
  .masthead {
    padding: var(--space-6);
    gap: var(--space-5);
  }
}

.masthead-top {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

@media (min-width: 768px) {
  .masthead-top {
    flex-direction: row;
    align-items: flex-start;
    justify-content: space-between;
    gap: var(--space-6);
  }
}

.brand {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  min-width: 0;
}

.mark {
  flex: 0 0 auto;
  display: grid;
  place-items: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-control);
  background: linear-gradient(140deg, var(--accent-indigo), var(--accent-violet));
  color: var(--accent-ink);
  font-family: var(--font-mono);
  font-size: var(--fs-small);
  font-weight: 700;
  letter-spacing: 0.04em;
}

.brand-text {
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 0;
}

.eyebrow {
  font-size: var(--fs-micro);
  font-weight: 600;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  color: var(--text-quaternary);
}

.site-title {
  font-size: var(--fs-h1);
  font-weight: 650;
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--text-primary);
}

/* ------------------------------------------------------------- the runway */

.runway {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
}

.runway-month {
  display: inline-block;
  padding: var(--space-2) var(--space-4);
  font-size: var(--fs-display);
  font-weight: 700;
  line-height: 1.05;
  letter-spacing: -0.03em;
  color: var(--text-primary);
  background: var(--surface-elevated);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-control);
}

.runway-month--cur {
  background:
    linear-gradient(var(--surface-elevated), var(--surface-elevated)) padding-box,
    linear-gradient(140deg, var(--accent-indigo), var(--accent-violet)) border-box;
  border: 1px solid transparent;
}

.runway-arrow {
  font-size: calc(var(--fs-display) * 0.6);
  font-weight: 400;
  line-height: 1;
  color: var(--accent-violet);
}

.runway[data-state="loading"] .runway-month,
.runway[data-state="loading"] .runway-arrow {
  color: var(--text-quaternary);
  border-color: var(--border-subtle);
  background: var(--surface-elevated);
}

.runway-month--prev {
  color: var(--text-tertiary);
}

/* ----------------------------------------------------------- masthead meta */

.masthead-meta {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: var(--space-2);
}

@media (min-width: 768px) {
  .masthead-meta {
    align-items: flex-end;
    text-align: right;
    flex: 0 0 auto;
  }
}

.updated {
  font-family: var(--font-mono);
  font-size: var(--fs-caption);
  color: var(--text-tertiary);
  font-variant-numeric: tabular-nums;
}

.source-link {
  font-size: var(--fs-small);
  font-weight: 600;
  padding-bottom: 1px;
  border-bottom: 1px solid var(--border-strong);
}

.source-link:hover {
  border-bottom-color: currentColor;
}

.source-note {
  font-size: var(--fs-caption);
  color: var(--text-quaternary);
}