/* Compact presentation fills one viewport without concealing overflow. */
body.single-screen {
  min-height: 100vh;
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
}
.single-screen .site-header {
  flex: 0 0 64px;
  height: 64px;
}
.single-screen #main-content {
  display: flex;
  flex: 1 0 auto;
  min-height: 0;
}
.single-screen .hero {
  display: flex;
  flex: 1;
  width: 100%;
  /* Clip decoration without creating a scroll container that focus can move. */
  overflow: clip;
}
.single-screen .hero-grid {
  flex: 0 1 auto;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: clamp(28px, 4vw, 64px);
  align-items: center;
  padding-block: clamp(20px, 4dvh, 44px);
}
.single-screen .hero-copy { padding-block: 0; }
.single-screen .hero h1 {
  font-size: clamp(34px, 3.6vw, 58px);
  line-height: 1.24;
}
.single-screen .hero-description {
  margin-top: 20px;
  font-size: clamp(14px, 1.3vw, 18px);
  line-height: 1.75;
}
.single-screen .hero-actions { margin-top: 24px; }
.single-screen .hero-principles { margin-top: 20px; }
.single-screen .hero-visual { padding-left: 0; }
.single-screen .preview-heading {
  height: 50px;
  padding-inline: 20px;
}
.single-screen .preview-tabs button { min-height: 44px; }
.single-screen .hero-panel {
  min-height: clamp(220px, 35dvh, 334px);
  padding: 18px 20px;
}
.single-screen .preview-question { padding-bottom: 14px; }
.single-screen .preview-answer { padding-block: 16px; }
.single-screen .preview-next { padding-top: 10px; }
.single-screen .preview-footer { padding: 9px 20px; }
.single-screen .site-footer { flex: 0 0 auto; }
.single-screen .footer-inner {
  display: flex;
  justify-content: center;
  padding-block: 9px;
  min-height: 34px;
  border-top: 0;
}
.single-screen .footer-inner > .brand,
.single-screen .footer-inner > p,
.single-screen .footer-top { display: none; }
.single-screen .footer-copyright { margin: 0; }

/* Short desktop windows keep content density modest rather than scaling text. */
@media (min-width: 768px) and (max-height: 720px) {
  .single-screen .hero-grid { padding-block: 16px; }
  .single-screen .hero h1 { font-size: clamp(32px, 3.5vw, 48px); }
  .single-screen .hero-description { margin-top: 16px; line-height: 1.65; }
  .single-screen .hero-actions { margin-top: 20px; }
  .single-screen .hero-principles { display: none; }
  .single-screen .preview-heading { height: 44px; }
  .single-screen .hero-panel { min-height: 220px; padding: 14px 18px; }
  .single-screen .preview-next { display: none; }
  .single-screen .panel-intro > p { display: none; }
  .single-screen .panel-intro h3 { margin-top: 6px; font-size: 18px; }
  .single-screen .hero-source-list { margin-top: 10px; }
  .single-screen .preview-action-list { margin-top: 12px; gap: 8px; }
  .single-screen .preview-footer { padding-block: 7px; }
}

@media (max-width: 767px) {
  .single-screen .site-header { flex-basis: 56px; height: 56px; }
  .single-screen .header-inner { gap: 12px; }
  .single-screen .header-actions { gap: 6px; }
  .single-screen .theme-toggle { width: 40px; }
  .single-screen .hero-grid {
    grid-template-columns: minmax(0, 1fr);
    align-content: center;
    gap: 18px;
    padding-block: 16px;
  }
  .single-screen .hero h1 {
    font-size: clamp(28px, 7.2vw, 36px);
    line-height: 1.22;
    letter-spacing: -1px;
  }
  .single-screen .hero-description {
    max-width: 450px;
    margin-top: 12px;
    font-size: 13px;
    line-height: 1.65;
  }
  .single-screen .hero-actions { margin-top: 18px; }
  .single-screen .hero-actions .button {
    min-height: 44px;
    padding: 10px 18px;
    font-size: 13px;
  }
  .single-screen .hero-principles { display: none; }
  .single-screen .hero-visual { padding: 0; max-width: 480px; }
  .single-screen .preview-heading { height: 40px; padding-inline: 16px; }
  .single-screen .preview-heading strong { font-size: 12px; }
  .single-screen .preview-tabs { padding-inline: 8px; }
  .single-screen .preview-tabs button { min-height: 44px; font-size: 12px; }
  .single-screen .hero-panel { min-height: 200px; padding: 14px 16px; }
  .single-screen .preview-question { padding-bottom: 8px; }
  .single-screen .preview-question > p { margin-top: 0; font-size: 12px; line-height: 1.5; }
  .single-screen .preview-question > .small-label,
  .single-screen .preview-answer .small-label,
  .single-screen .preview-answer > .answer-avatar,
  .single-screen .preview-next,
  .single-screen .panel-intro > .small-label,
  .single-screen .panel-intro > p { display: none; }
  .single-screen .preview-answer { padding: 10px 0 0; gap: 8px; }
  .single-screen .preview-answer p { margin-top: 0; font-size: 12px; line-height: 1.65; }
  .single-screen .inline-evidence { margin-top: 8px; font-size: 12px; }
  .single-screen .panel-intro h3 { margin-top: 0; font-size: 18px; line-height: 1.4; }
  .single-screen .hero-source-list { margin-top: 10px; }
  .single-screen .hero-source-list .source-row { min-height: 52px; padding: 7px 9px; margin-bottom: 6px; }
  .single-screen .hero-source-list .source-row strong,
  .single-screen .hero-source-list .source-row small { font-size: 12px; line-height: 1.5; }
  .single-screen .preview-action-list { margin-top: 12px; gap: 8px; }
  .single-screen .preview-action-list li { gap: 9px; }
  .single-screen .preview-action-list strong,
  .single-screen .preview-action-list p { font-size: 12px; line-height: 1.5; }
  .single-screen .preview-action-list p { margin-top: 0; }
  .single-screen .preview-footer { padding: 6px 16px; font-size: 12px; line-height: 1.4; }
  .single-screen .preview-footer > span:not(.preview-disclosure) { display: none; }
  .single-screen .preview-disclosure { margin-left: 0; }
  .single-screen .footer-inner { min-height: 30px; padding-block: 7px; }
}

/* Small portrait devices retain the title, login and all three preview views. */
@media (max-width: 767px) and (max-height: 640px) {
  .single-screen .hero-grid { padding-block: 10px; gap: 12px; }
  .single-screen .hero-description { display: none; }
  .single-screen .hero h1 { font-size: 28px; }
  .single-screen .hero-actions { margin-top: 14px; }
  .single-screen .preview-heading { height: 38px; }
  .single-screen .hero-panel { min-height: 185px; padding: 12px 14px; }
  .single-screen .preview-footer { padding-block: 5px; }
}

/* A very short landscape window prioritizes readable introduction and login. */
@media (max-width: 1100px) and (max-height: 500px) {
  .single-screen .hero-grid {
    grid-template-columns: minmax(0, 1fr);
    padding-block: 16px;
  }
  .single-screen .hero-copy { max-width: 680px; }
  .single-screen .hero-visual { display: none; }
  .single-screen .hero-principles { display: none; }
  .single-screen .hero-actions { margin-top: 18px; }
}