:root {
  --ink: #172f38;
  --ink-soft: #53666a;
  --paper: #f7f2e8;
  --paper-deep: #ede4d3;
  --card: rgba(255, 253, 248, 0.92);
  --teal: #087f78;
  --teal-dark: #075f5b;
  --gold: #c48b28;
  --gold-pale: #f1ddb5;
  --line: #d8cebd;
  --shadow: 0 24px 70px rgba(37, 54, 55, 0.13);
}

* { box-sizing: border-box; }

html { min-height: 100%; }

body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  background:
    radial-gradient(circle at 12% 4%, rgba(196, 139, 40, 0.13), transparent 27rem),
    radial-gradient(circle at 91% 23%, rgba(8, 127, 120, 0.09), transparent 30rem),
    repeating-linear-gradient(0deg, rgba(23, 47, 56, 0.018) 0, rgba(23, 47, 56, 0.018) 1px, transparent 1px, transparent 5px),
    var(--paper);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

button, input { font: inherit; }

button { -webkit-tap-highlight-color: transparent; }

.page-shell {
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto;
  padding: 64px 0 28px;
}

.hero {
  position: relative;
  padding: 18px 0 46px;
  text-align: center;
}

.hero::after {
  content: "";
  position: absolute;
  bottom: 22px;
  left: 50%;
  width: 86px;
  height: 2px;
  transform: translateX(-50%);
  background: linear-gradient(90deg, transparent, var(--gold), transparent);
}

.eyebrow {
  margin: 0 0 18px;
  color: var(--teal-dark);
  font-size: 0.75rem;
  font-weight: 750;
  letter-spacing: 0.17em;
  text-transform: uppercase;
}

h1, h2, h3, p { margin-top: 0; }

h1 {
  margin-bottom: 9px;
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(2rem, 5vw, 4.2rem);
  font-weight: 500;
  letter-spacing: -0.045em;
  line-height: 1;
}

.title-join {
  color: var(--ink-soft);
  font-size: 0.48em;
  font-style: italic;
}

.hero-formula {
  display: inline-flex;
  align-items: flex-start;
  gap: 0.08em;
  margin: 6px 0 22px;
  color: var(--teal-dark);
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(2.8rem, 8vw, 6.3rem);
  font-style: italic;
  letter-spacing: -0.055em;
  line-height: 0.95;
  text-shadow: 0 2px 0 white;
}

.hero-formula sup {
  margin-left: 0.03em;
  color: var(--gold);
  font-size: 0.38em;
  font-style: normal;
}

.hero-sign {
  margin: 0 0.16em;
  color: var(--gold);
  font-style: normal;
  font-weight: 400;
}

.intro {
  max-width: 700px;
  margin: 0 auto;
  color: var(--ink-soft);
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(1rem, 2vw, 1.2rem);
  line-height: 1.65;
}

.calculator-card, .result-card {
  border: 1px solid rgba(125, 111, 88, 0.24);
  border-radius: 24px;
  background: var(--card);
  box-shadow: var(--shadow);
  backdrop-filter: blur(10px);
}

.calculator-card { padding: clamp(24px, 4vw, 46px); }

.section-heading {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  margin-bottom: 30px;
}

.step-number {
  display: grid;
  flex: 0 0 38px;
  width: 38px;
  height: 38px;
  place-items: center;
  border: 1px solid var(--gold);
  border-radius: 50%;
  color: var(--gold);
  font-family: Georgia, "Times New Roman", serif;
  font-size: 0.86rem;
}

.section-heading h2 {
  margin-bottom: 5px;
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(1.45rem, 3vw, 2rem);
  font-weight: 500;
}

.section-heading p { margin-bottom: 0; color: var(--ink-soft); }

.expression-builder {
  display: flex;
  align-items: end;
  justify-content: center;
  gap: clamp(7px, 1.7vw, 18px);
  padding: clamp(21px, 4vw, 38px);
  border: 1px solid var(--line);
  border-radius: 18px;
  background: rgba(247, 242, 232, 0.65);
}

.number-field {
  position: relative;
  display: block;
  width: min(180px, 22vw);
}

.number-field > span {
  position: absolute;
  top: -0.76rem;
  left: 14px;
  z-index: 1;
  padding: 0 7px;
  color: var(--teal-dark);
  background: #f9f5ec;
  font-family: Georgia, "Times New Roman", serif;
  font-size: 1.1rem;
  font-style: italic;
}

.number-field input,
.mirrored-exponent output {
  display: block;
  width: 100%;
  height: 56px;
  min-width: 0;
  padding: 15px 14px 13px;
  border: 1px solid #bcb09d;
  border-radius: 12px;
  outline: none;
  color: var(--ink);
  background: rgba(255, 255, 255, 0.74);
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  font-size: clamp(1rem, 2.5vw, 1.35rem);
  transition: border-color 150ms ease, box-shadow 150ms ease, background 150ms ease;
}

.mirrored-exponent output {
  overflow: hidden;
  white-space: nowrap;
}

.number-field input:hover {
  border-color: rgba(8, 127, 120, 0.72);
  background: rgba(255, 255, 255, 0.92);
  box-shadow: 0 0 0 3px rgba(8, 127, 120, 0.08);
}

.number-field input:focus {
  border-color: var(--teal);
  background: white;
  box-shadow: 0 0 0 4px rgba(8, 127, 120, 0.12);
}

.compact-field { width: min(105px, 16vw); }

.exponent-field { transform: translateY(-50%); }

.sign-toggle {
  position: relative;
  flex: 0 0 70px;
  width: 70px;
  height: 56px;
  padding: 0;
  overflow: hidden;
  border: 0;
  border-radius: 16px;
  outline: none;
  background: transparent;
  cursor: pointer;
  filter: drop-shadow(0 6px 10px rgba(7, 95, 91, 0.15));
}

.sign-toggle canvas { display: block; width: 100%; height: 100%; }
.sign-toggle:focus-visible { box-shadow: 0 0 0 4px rgba(8, 127, 120, 0.2); }

.input-note {
  margin: 14px 0 0;
  color: var(--ink-soft);
  font-size: 0.82rem;
  text-align: center;
}

.normalization-option {
  display: flex;
  width: fit-content;
  margin: 16px auto 0;
  padding: 8px 13px;
  align-items: center;
  gap: 9px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--ink);
  background: rgba(255, 255, 255, 0.5);
  font-size: 0.88rem;
  font-weight: 700;
  cursor: pointer;
}

.normalization-option input {
  width: 18px;
  height: 18px;
  margin: 0;
  accent-color: var(--teal);
  cursor: pointer;
}

.normalization-option:focus-within {
  outline: 3px solid rgba(8, 127, 120, 0.15);
  outline-offset: 2px;
}

.assumption-note {
  display: block;
  margin-top: 5px;
  color: var(--teal-dark);
  font-weight: 750;
}

.action-row {
  display: flex;
  justify-content: center;
  gap: 12px;
  margin-top: 25px;
}

.primary-button, .secondary-button {
  min-width: 132px;
  padding: 12px 20px;
  border-radius: 999px;
  font-weight: 760;
  letter-spacing: 0.02em;
  cursor: pointer;
  transition: transform 150ms ease, background 150ms ease, box-shadow 150ms ease, color 150ms ease;
}

.primary-button {
  border: 1px solid var(--teal-dark);
  color: white;
  background: var(--teal);
  box-shadow: 0 8px 20px rgba(8, 127, 120, 0.2);
}

.primary-button:hover:not(:disabled) { transform: translateY(-1px); background: var(--teal-dark); }

.primary-button:disabled {
  border-color: #b7b8b3;
  color: #f1f1ed;
  background: #aaada8;
  box-shadow: none;
  cursor: not-allowed;
}

.secondary-button { border: 1px solid #9e927f; color: var(--ink); background: transparent; }
.secondary-button:hover { transform: translateY(-1px); background: var(--paper-deep); }

.results { margin-top: 32px; }

.result-card {
  margin-bottom: 20px;
  padding: clamp(23px, 4vw, 42px);
}

.result-hero {
  color: white;
  border-color: transparent;
  background: linear-gradient(130deg, var(--teal-dark), #0a7770 62%, #17645f);
  box-shadow: 0 25px 70px rgba(7, 95, 91, 0.23);
}

.result-kicker {
  margin-bottom: 10px;
  color: #c6e5df;
  font-size: 0.73rem;
  font-weight: 800;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.result-expression {
  display: block;
  width: 100%;
  min-width: 0;
  padding: 0 0 8px;
  overflow-x: auto;
  overflow-y: hidden;
  border: 0;
  outline: 0;
  background: transparent;
  white-space: nowrap;
  margin-bottom: 8px;
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(1.19rem, 3.5vw, 2.24rem);
  font-weight: 500;
  line-height: 1.05;
  scrollbar-color: #e4bc68 rgba(255, 255, 255, 0.16);
  scrollbar-width: auto;
}

.result-expression-content {
  display: inline-block;
  min-width: max-content;
}

.result-expression mjx-container {
  margin: 0 !important;
}

.result-expression::-webkit-scrollbar { height: 9px; }
.result-expression::-webkit-scrollbar-track { border-radius: 999px; background: rgba(255, 255, 255, 0.16); }
.result-expression::-webkit-scrollbar-thumb { border-radius: 999px; background: #e4bc68; }

.result-expression:focus-visible {
  outline: 2px solid rgba(255, 242, 207, 0.72);
  outline-offset: 2px;
}

.exact-value {
  margin: 0;
  color: #fff2cf;
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  font-size: clamp(1rem, 3vw, 1.45rem);
  overflow-wrap: anywhere;
}

.result-card h2 {
  margin-bottom: 22px;
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(1.35rem, 3vw, 1.9rem);
  font-weight: 500;
}

.math-block {
  margin: 15px 0;
  padding: 15px 18px;
  overflow-x: auto;
  border-left: 3px solid var(--gold);
  background: rgba(241, 221, 181, 0.23);
  font-family: Georgia, "Times New Roman", serif;
}

.math-block mjx-container[display="true"] { margin: 0 !important; text-align: left !important; }

.factor-list {
  display: grid;
  gap: 10px;
  margin: 19px 0 0;
  padding: 0;
  list-style: none;
}

.factor-row {
  display: grid;
  grid-template-columns: minmax(0, 1.25fr) minmax(0, 1fr);
  gap: 16px;
  align-items: start;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.56);
}

.factor-name {
  min-width: 0;
  color: var(--teal-dark);
  font-family: Georgia, "Times New Roman", serif;
  font-size: 1.05rem;
  line-height: 1.55;
}

.wrappable-phi sub {
  font-size: 0.7em;
  line-height: 0;
}

.factor-value {
  min-width: 0;
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  font-variant-numeric: tabular-nums;
  line-height: 1.55;
  overflow-wrap: normal;
}

.identity-stack { display: grid; gap: 17px; }

.identity-card {
  position: relative;
  padding: 21px;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.53);
}

.identity-card::before {
  content: "";
  position: absolute;
  inset: 0 auto 0 0;
  width: 4px;
  background: var(--teal);
}

.identity-label {
  margin-bottom: 8px;
  color: var(--gold);
  font-size: 0.72rem;
  font-weight: 850;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.identity-card h3 { margin-bottom: 10px; font-family: Georgia, "Times New Roman", serif; font-size: 1.27rem; font-weight: 500; }
.identity-card p:last-child { margin-bottom: 0; }
.identity-rule { color: var(--ink-soft); }
.identity-use { padding-top: 11px; border-top: 1px solid var(--line); }
.verification {
  border-color: rgba(8, 127, 120, 0.24);
  background: linear-gradient(135deg, rgba(221, 240, 233, 0.75), rgba(255, 253, 248, 0.93));
}

.verification-mark {
  display: inline-grid;
  width: 31px;
  height: 31px;
  margin-right: 9px;
  place-items: center;
  border-radius: 50%;
  color: white;
  background: var(--teal);
  font-family: sans-serif;
  font-size: 0.9rem;
}

.primality-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 9px 18px;
  margin: -8px 0 20px;
  color: var(--ink-soft);
  font-size: 0.78rem;
}

.primality-legend > span {
  display: inline-flex;
  align-items: center;
  gap: 7px;
}

.legend-swatch {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}

.prime-swatch { background: #b42318; }
.composite-swatch { background: #1859a9; }

.verification-equation {
  color: var(--ink);
  font-family: Cambria, "Times New Roman", serif;
  font-size: clamp(1.05rem, 2.4vw, 1.32rem);
  font-weight: 600;
  white-space: nowrap;
}

.verification-equation > div {
  display: flex;
  width: max-content;
  min-width: 100%;
  align-items: baseline;
  gap: 0.38em;
}

.verification-number.prime,
.verification-number.probable-prime {
  color: #b42318;
}

.verification-number.composite {
  color: #1859a9;
}

.verification-operator {
  color: var(--ink);
  font-weight: 500;
}

.refined-check {
  margin-top: 24px;
  padding-top: 20px;
  border-top: 1px solid rgba(8, 127, 120, 0.24);
}

.refined-check .math-block {
  border-left-color: var(--teal);
  background: rgba(8, 127, 120, 0.08);
}

.normalization-card {
  border-color: rgba(196, 139, 40, 0.36);
  background: linear-gradient(135deg, rgba(255, 249, 235, 0.95), rgba(255, 253, 248, 0.92));
}

.working-values {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
  margin-top: 20px;
}

.working-values > span {
  display: grid;
  gap: 4px;
  padding: 13px 15px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.65);
}

.working-values small {
  color: var(--ink-soft);
  font-size: 0.72rem;
  font-weight: 750;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.working-values strong {
  color: var(--teal-dark);
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  font-size: 1.12rem;
  overflow-wrap: anywhere;
}

.error-card { border-color: #b96652; background: #fff4ef; }

.assumption-list {
  display: grid;
  gap: 10px;
  margin: 16px 0 0;
  padding-left: 22px;
}

.gcd-help {
  margin-top: 24px;
  padding-top: 22px;
  border-top: 1px solid rgba(185, 102, 82, 0.3);
}

.gcd-help h3 {
  margin-bottom: 10px;
  font-family: Georgia, "Times New Roman", serif;
  font-size: 1.3rem;
  font-weight: 500;
}

.gcd-help .math-block {
  border-left-color: #b96652;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

@media (max-width: 700px) {
  .page-shell { width: min(100% - 20px, 1120px); padding-top: 36px; }
  .calculator-card, .result-card { border-radius: 18px; }
  .expression-builder { flex-wrap: wrap; }
  .number-field { width: 125px; }
  .compact-field { width: 78px; }
  .sign-toggle { flex-basis: 62px; width: 62px; }
  .factor-row { grid-template-columns: 1fr; gap: 5px; }
}

@media (max-width: 430px) {
  .expression-builder { gap: 10px 6px; }
  .number-field { width: 114px; }
  .compact-field { width: 72px; }
  .sign-toggle { order: 5; flex-basis: 100%; width: 100%; margin-top: 8px; }
  .action-row { flex-direction: column; }
  .primary-button, .secondary-button { width: 100%; }
  .working-values { grid-template-columns: 1fr; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; transition: none !important; }
}