:root {
  color-scheme: dark;
  font-family:
    -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial,
    sans-serif;
  --page: #050b14;
  --card: #0b1627;
  --surface: #111f34;
  --surface-raised: #16253b;
  --surface-blue: #0e2541;
  --border: #263750;
  --border-strong: #3a4b64;
  --text: #f5f8fc;
  --text-soft: #dbe4ef;
  --muted: #a7b5c8;
  --muted-strong: #c1ccda;
  --blue: #3a8dff;
  --blue-strong: #66a7ff;
  --blue-deep: #2475e5;
  --teal: #55d5ca;
  --focus: #8ec0ff;
  --green: #52b788;
  --green-text: #d7f5e5;
  --green-surface: #102d27;
  --red: #df737b;
  --red-text: #ffe0e2;
  --red-surface: #342027;
}

* {
  box-sizing: border-box;
}

html {
  min-width: 320px;
  background: var(--page);
}

body {
  min-width: 320px;
  min-height: 100vh;
  margin: 0;
  color: var(--text);
  background:
    radial-gradient(circle at 50% 0%, rgb(32 71 121 / 15%), transparent 32rem),
    var(--page);
}

button {
  font: inherit;
}

.app-shell {
  display: grid;
  min-height: 100vh;
  place-items: start center;
  padding: 1rem 0.75rem 0.75rem;
}

.card {
  width: min(100%, 720px);
  padding: 1.25rem;
  overflow: hidden;
  background: var(--card);
  border: 1px solid rgb(142 192 255 / 16%);
  border-radius: 0.9rem;
  box-shadow: 0 1.25rem 3.5rem rgb(0 0 0 / 18%);
}

.brand-lockup {
  display: flex;
  gap: 0.7rem;
  align-items: center;
  margin-bottom: 1.75rem;
  padding-bottom: 1rem;
  color: var(--muted-strong);
  font-size: 0.72rem;
  font-weight: 760;
  letter-spacing: 0.17em;
  border-bottom: 1px solid rgb(167 181 200 / 15%);
}

.brand-mark {
  position: relative;
  display: inline-block;
  width: 1.55rem;
  height: 0.78rem;
}

.brand-mark::before,
.brand-mark::after {
  position: absolute;
  top: 0;
  width: 0.48rem;
  height: 0.78rem;
  border-radius: 0.08rem;
  transform: skewX(-28deg);
  content: "";
}

.brand-mark::before {
  left: 0.25rem;
  background: var(--teal);
}

.brand-mark::after {
  right: 0.25rem;
  background: var(--blue);
}

h1,
h2,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 1rem;
  color: var(--text);
  font-size: clamp(2rem, 9vw, 3.25rem);
  font-weight: 720;
  line-height: 1.06;
  letter-spacing: -0.04em;
}

h2 {
  margin-bottom: 1.25rem;
  color: var(--text);
  font-size: clamp(1.32rem, 5.5vw, 1.75rem);
  font-weight: 680;
  line-height: 1.32;
  letter-spacing: -0.02em;
}

.eyebrow,
.question-count {
  margin: 0 0 0.55rem;
  color: var(--blue-strong);
  font-size: 0.75rem;
  font-weight: 760;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.intro-copy,
.result-note,
.time-note {
  color: var(--muted);
  font-size: 1rem;
  line-height: 1.65;
}

.intro-copy {
  max-width: 60ch;
  margin-bottom: 1.25rem;
}

.commitment-line {
  margin-bottom: 1.75rem;
  color: var(--text-soft);
  font-size: 0.9rem;
  font-weight: 650;
}

.start-action {
  display: flex;
  flex-direction: column;
  align-items: stretch;
}

.helper-text {
  margin: 0.7rem 0 0;
  color: var(--muted);
  font-size: 0.82rem;
  text-align: center;
}

.primary-button,
.secondary-button,
.answer-button {
  min-height: 3rem;
  border-radius: 0.55rem;
  cursor: pointer;
  transition:
    background-color 140ms ease,
    border-color 140ms ease,
    color 140ms ease,
    transform 100ms ease;
}

.primary-button {
  padding: 0.82rem 1.25rem;
  color: #fff;
  font-weight: 720;
  background: var(--blue-deep);
  border: 1px solid var(--blue);
  box-shadow: 0 0.35rem 1rem rgb(20 91 190 / 20%);
}

.primary-button:hover {
  background: #2f82f3;
  border-color: var(--blue-strong);
}

.secondary-button {
  padding: 0.78rem 1.1rem;
  color: var(--muted-strong);
  font-weight: 650;
  background: transparent;
  border: 1px solid var(--border-strong);
}

.secondary-button:hover {
  color: var(--text);
  background: var(--surface);
  border-color: var(--muted);
}

.primary-button:active,
.secondary-button:active,
.answer-button:active:not(:disabled) {
  transform: translateY(1px);
}

button:focus-visible,
[tabindex="-1"]:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 3px;
}

.question-count {
  color: var(--muted-strong);
}

.progress-track {
  position: relative;
  width: 100%;
  height: 0.28rem;
  margin-bottom: 1.45rem;
  overflow: hidden;
  background: #1e2d43;
  border-radius: 999px;
}

.progress-track::before,
.progress-track::after {
  position: absolute;
  z-index: 2;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--card);
  content: "";
}

.progress-track::before {
  left: 33.333%;
}

.progress-track::after {
  left: 66.666%;
}

.progress-fill {
  height: 100%;
  background: var(--blue);
  border-radius: inherit;
  transition: width 160ms ease;
}

.situation {
  margin-bottom: 1.55rem;
  padding: 1.1rem;
  color: var(--text-soft);
  line-height: 1.6;
  background: var(--surface-blue);
  border: 1px solid rgb(102 167 255 / 18%);
  border-left: 3px solid var(--blue);
  border-radius: 0.55rem;
}

.situation p:last-child {
  margin-bottom: 0;
}

.math-display {
  margin: 0.8rem 0 0;
  color: var(--text);
  font-family: "Cambria Math", Cambria, "STIX Two Math", serif;
  font-size: clamp(1.45rem, 7vw, 1.85rem);
  font-weight: 600;
  line-height: 1.4;
  text-align: center;
  letter-spacing: 0.01em;
}

.situation > .math-display:first-child {
  margin-top: 0;
}

.answer-list {
  display: grid;
  gap: 0.7rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.answer-button {
  display: grid;
  grid-template-columns: 2.1rem minmax(0, 1fr);
  align-items: center;
  width: 100%;
  min-height: 3.4rem;
  padding: 0.8rem 0.95rem;
  color: var(--text-soft);
  line-height: 1.4;
  text-align: left;
  background: var(--surface);
  border: 1px solid var(--border);
}

.answer-button:hover:not(:disabled) {
  color: var(--text);
  background: var(--surface-raised);
  border-color: var(--blue);
}

.answer-letter {
  display: grid;
  width: 1.65rem;
  height: 1.65rem;
  place-items: center;
  color: var(--blue-strong);
  font-size: 0.78rem;
  font-weight: 800;
  background: rgb(58 141 255 / 10%);
  border: 1px solid rgb(102 167 255 / 24%);
  border-radius: 0.3rem;
}

.answer-button:disabled {
  cursor: default;
  opacity: 1;
}

.answer-button:disabled:not(.selected) {
  color: var(--muted-strong);
  background: #0f1c2e;
  border-color: #213047;
}

.answer-button.selected.correct {
  color: var(--green-text);
  background: var(--green-surface);
  border-color: var(--green);
}

.answer-button.selected.incorrect {
  color: var(--text-soft);
  background: #121f32;
  border-color: var(--red);
}

.answer-button.selected.correct .answer-letter {
  color: inherit;
  background: rgb(255 255 255 / 6%);
  border-color: currentColor;
}

.answer-button.selected.incorrect .answer-letter {
  color: var(--red);
  background: rgb(223 115 123 / 8%);
  border-color: rgb(223 115 123 / 70%);
}

.feedback {
  margin: 1rem 0 0;
  padding: 1rem;
  color: var(--text-soft);
  line-height: 1.58;
  border-radius: 0.55rem;
}

.feedback.correct {
  background: var(--green-surface);
  border: 1px solid rgb(82 183 136 / 55%);
}

.feedback.incorrect {
  background: #101d30;
  border: 1px solid var(--border);
  border-left: 3px solid var(--red);
}

.feedback-status {
  display: block;
  margin-bottom: 0.35rem;
  font-size: 0.75rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.feedback.correct .feedback-status {
  color: var(--green);
}

.feedback.incorrect .feedback-status {
  color: var(--red);
}

.feedback p {
  margin-bottom: 0;
}

.continue-row {
  display: flex;
  margin-top: 1rem;
}

.continue-row .primary-button {
  width: 100%;
}

.diagram-situation {
  padding: 0.7rem;
  border-left-width: 1px;
}

.triangle-diagram {
  display: block;
  width: min(100%, 430px);
  height: auto;
  margin: 0 auto;
}

.triangle-diagram .triangle-shape,
.triangle-diagram .parallel-segment,
.triangle-diagram .parallel-mark {
  fill: none;
  stroke-linecap: round;
  stroke-linejoin: round;
  vector-effect: non-scaling-stroke;
}

.triangle-diagram .triangle-shape {
  stroke: var(--text-soft);
  stroke-width: 2.25;
}

.triangle-diagram .parallel-segment {
  stroke: var(--blue-strong);
  stroke-width: 2.5;
}

.triangle-diagram .parallel-mark {
  stroke: var(--blue-strong);
  stroke-width: 1.6;
}

.triangle-diagram .point {
  fill: var(--blue-strong);
}

.triangle-diagram text {
  fill: var(--text);
  stroke: var(--surface-blue);
  stroke-width: 5px;
  paint-order: stroke fill;
  font-family:
    -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial,
    sans-serif;
  font-size: 15px;
  font-weight: 720;
}

.triangle-diagram .measure {
  fill: var(--blue-strong);
  font-family: "Cambria Math", Cambria, "STIX Two Math", serif;
  font-size: 17px;
  font-style: italic;
  font-weight: 700;
}

.results-screen h1 {
  max-width: 16ch;
  margin-bottom: 1.25rem;
  font-size: clamp(1.9rem, 8vw, 2.8rem);
}

.score-display {
  margin: 0 0 0.35rem;
  color: var(--text);
  font-size: clamp(3.25rem, 16vw, 5.25rem);
  font-weight: 760;
  line-height: 0.98;
  letter-spacing: -0.065em;
}

.completion-time {
  margin-bottom: 1.8rem;
  color: var(--muted-strong);
  font-size: 0.95rem;
  font-weight: 620;
}

.category-results {
  display: grid;
  gap: 0.6rem;
  margin: 0 0 1.5rem;
}

.category-result {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 0.8rem;
  align-items: center;
  margin: 0;
  padding: 0.9rem 1rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 0.55rem;
}

.category-result dt {
  color: var(--text-soft);
  font-weight: 680;
  line-height: 1.35;
}

.category-result dd {
  display: flex;
  flex-direction: column;
  gap: 0.12rem;
  align-items: flex-end;
  margin: 0;
  text-align: right;
}

.category-score {
  color: var(--text);
  font-size: 0.9rem;
  font-weight: 760;
  white-space: nowrap;
}

.category-label {
  color: var(--blue-strong);
  font-size: 0.78rem;
  font-weight: 650;
  white-space: nowrap;
}

.diagnostic-section {
  margin-bottom: 1.25rem;
  padding: 1.1rem;
  background: #0e1f35;
  border: 1px solid rgb(102 167 255 / 22%);
  border-left: 3px solid var(--blue);
  border-radius: 0.55rem;
}

.diagnostic-eyebrow {
  margin: 0 0 0.45rem;
  color: var(--blue-strong);
  font-size: 0.7rem;
  font-weight: 780;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.diagnostic-headline {
  margin-bottom: 0.65rem;
  font-size: clamp(1.15rem, 4.8vw, 1.4rem);
  line-height: 1.3;
}

.diagnostic-text {
  max-width: 62ch;
  margin-bottom: 0;
  color: var(--text-soft);
  font-size: 0.94rem;
  line-height: 1.62;
}

.result-note {
  margin-bottom: 1rem;
  font-size: 0.9rem;
}

.time-note {
  margin-bottom: 1rem;
  padding: 0.9rem 1rem;
  color: var(--muted-strong);
  font-size: 0.88rem;
  background: var(--surface-blue);
  border: 1px solid rgb(102 167 255 / 20%);
  border-left: 3px solid var(--blue);
  border-radius: 0.45rem;
}

.next-step-section {
  margin-top: 1.35rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
}

.next-step-eyebrow {
  margin: 0 0 0.45rem;
  color: var(--blue-strong);
  font-size: 0.7rem;
  font-weight: 780;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.next-step-headline {
  margin-bottom: 0.55rem;
  font-size: clamp(1.2rem, 5vw, 1.5rem);
  line-height: 1.3;
}

.next-step-copy {
  max-width: 58ch;
  margin-bottom: 1rem;
  color: var(--muted-strong);
  font-size: 0.94rem;
  line-height: 1.6;
}

.next-step-primary {
  display: inline-flex;
  width: 100%;
  align-items: center;
  justify-content: center;
  text-align: center;
  text-decoration: none;
}

.newsletter-action {
  margin-top: 1.25rem;
  text-align: center;
}

.newsletter-heading {
  margin: 0 0 0.3rem;
  color: var(--text-soft);
  font-size: 1rem;
  font-weight: 680;
  line-height: 1.4;
}

.newsletter-support {
  margin: 0 0 0.75rem;
  color: var(--muted);
  font-size: 0.82rem;
  line-height: 1.5;
}

.newsletter-button {
  display: inline-flex;
  width: 100%;
  min-height: 3rem;
  padding: 0.75rem 1.1rem;
  align-items: center;
  justify-content: center;
  color: var(--text);
  font-size: 0.92rem;
  font-weight: 700;
  text-align: center;
  text-decoration: none;
  background: var(--surface);
  border: 1px solid var(--blue);
  border-radius: 0.55rem;
  transition:
    background-color 140ms ease,
    border-color 140ms ease;
}

.newsletter-button:hover {
  background: var(--surface-raised);
  border-color: var(--blue-strong);
}

.next-step-section a:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 3px;
}

.result-actions {
  margin-top: 1.35rem;
}

.result-actions .secondary-button {
  width: 100%;
}

@media (min-width: 560px) {
  .app-shell {
    padding: 1.25rem 2rem 2rem;
  }

  .card {
    padding: clamp(2rem, 5vw, 3rem);
    border-radius: 1rem;
  }

  .brand-lockup {
    margin-bottom: 2.2rem;
  }

  .start-action {
    align-items: flex-start;
  }

  .helper-text {
    padding-left: 0.2rem;
    text-align: left;
  }

  .answer-button {
    min-height: 3.65rem;
    padding: 0.9rem 1.1rem;
  }

  .continue-row {
    justify-content: flex-end;
  }

  .continue-row .primary-button,
  .result-actions .secondary-button,
  .next-step-primary {
    width: auto;
  }

  .newsletter-action {
    text-align: left;
  }

  .newsletter-button {
    width: auto;
  }

  .category-result dd {
    flex-direction: row;
    gap: 1rem;
    align-items: center;
  }
}

@media (min-width: 1024px) {
  .app-shell {
    place-items: center;
    padding: 2rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
  }
}