/* 1. reset/base */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body,
h1,
h2,
h3,
h4,
p,
ol,
ul {
  margin: 0;
}

body {
  min-height: 100vh;
  background: var(--color-background);
  color: var(--color-text);
}

img,
svg {
  max-width: 100%;
  display: block;
}

a {
  color: inherit;
}

button,
input,
textarea,
select {
  font: inherit;
}

button {
  cursor: pointer;
}

button:disabled {
  cursor: not-allowed;
}

[hidden] {
  display: none !important;
}

:focus-visible {
  outline: 3px solid var(--color-accent);
  outline-offset: 3px;
}

/* 2. tokens */
:root {
  --color-primary-navy: #143D59;
  --color-secondary-teal: #1F7A8C;
  --color-muted-gold: #B08D57;
  --color-surface-white: #FFFFFF;
  --color-primary: #143D59;
  --color-secondary: #1F7A8C;
  --color-accent: #B08D57;
  --color-background: #F7FAFC;
  --color-surface: #FFFFFF;
  --color-text: #102A43;
  --color-muted: #5B7083;
  --color-border: #D9E2EC;
  --color-primary-dark: #0f3047;
  --color-soft-blue: #eef5f8;
  --color-soft-teal: #eef8fa;
  --color-soft-gray: #eef2f5;
  --color-soft-gold: #fbf8f2;
  --color-white: #ffffff;

  --font-stack: "Source Sans 3", Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.5rem;
  --space-6: 2rem;
  --space-7: 3rem;
  --space-8: 4rem;
  --radius-sm: 6px;
  --radius-md: 8px;
  --shadow-sm: 0 1px 2px rgba(16, 42, 67, 0.06);
  --shadow-md: 0 12px 28px rgba(16, 42, 67, 0.08);
  --max-width: 1120px;
}

/* 3. typography */
body {
  font-family: var(--font-stack);
  font-size: 16px;
  line-height: 1.6;
  font-variant-numeric: tabular-nums;
}

h1,
h2,
h3,
h4 {
  color: var(--color-text);
  line-height: 1.2;
  font-weight: 750;
}

h1 {
  font-size: 2.35rem;
  letter-spacing: 0;
  max-width: 11ch;
}

h2 {
  font-size: 1.8rem;
  letter-spacing: 0;
}

h3 {
  font-size: 1.2rem;
}

h4 {
  font-size: 1rem;
}

p {
  color: var(--color-muted);
}

.hero-subtitle,
.page-hero p,
.section-heading p {
  font-size: 1.06rem;
}

.section-label {
  color: var(--color-secondary);
  font-size: 0.9rem;
  font-weight: 750;
  letter-spacing: 0;
}

.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;
}

/* 4. layout */
.container {
  width: min(100% - 2rem, var(--max-width));
  margin-inline: auto;
}

.narrow {
  max-width: 760px;
}

.section {
  padding: var(--space-8) 0;
}

.section-muted {
  background: var(--color-soft-blue);
}

.section-heading {
  display: grid;
  gap: var(--space-3);
  max-width: 760px;
  margin-bottom: var(--space-6);
}

.section-heading.centered {
  justify-items: center;
  text-align: center;
  margin-inline: auto;
}

.page-hero {
  padding: var(--space-7) 0 var(--space-6);
  background: linear-gradient(180deg, var(--color-white) 0%, var(--color-background) 100%);
  border-bottom: 1px solid var(--color-border);
}

.page-hero .container {
  display: grid;
  gap: var(--space-3);
}

.page-hero h1 {
  max-width: 14ch;
}

.content-stack {
  display: grid;
  gap: var(--space-4);
  max-width: 860px;
}

.card-grid,
.three-column,
.step-grid,
.callout-grid,
.tool-list {
  display: grid;
  gap: var(--space-4);
}

.trust-strip-section {
  padding: var(--space-5) 0 0;
}

/* 5. header/nav */
.skip-link {
  position: absolute;
  top: var(--space-3);
  left: var(--space-3);
  z-index: 20;
  transform: translateY(-150%);
  background: var(--color-surface);
  color: var(--color-primary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: var(--space-2) var(--space-3);
  font-weight: 700;
}

.skip-link:focus {
  transform: translateY(0);
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(255, 255, 255, 0.96);
  border-bottom: 1px solid var(--color-border);
}

.header-inner {
  min-height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  text-decoration: none;
  color: var(--color-primary);
  font-weight: 800;
}

.brand-mark {
  display: inline-grid;
  place-items: center;
  width: 2.4rem;
  height: 2.4rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-soft-blue);
  color: var(--color-primary);
  font-size: 0.82rem;
  letter-spacing: 0;
}

.brand-text {
  font-size: 1rem;
}

.brand-name,
.brand-line {
  display: block;
  line-height: 1.2;
}

.brand-name {
  font-size: 1rem;
}

.brand-line {
  max-width: 18rem;
  color: var(--color-muted);
  font-size: 0.78rem;
  font-weight: 650;
}

.nav-toggle {
  display: inline-grid;
  place-items: center;
  width: 2.75rem;
  height: 2.75rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-surface);
  color: var(--color-primary);
}

.nav-toggle-line,
.nav-toggle-line::before,
.nav-toggle-line::after {
  display: block;
  width: 1.2rem;
  height: 2px;
  background: currentColor;
  content: "";
}

.nav-toggle-line {
  position: relative;
}

.nav-toggle-line::before,
.nav-toggle-line::after {
  position: absolute;
  left: 0;
}

.nav-toggle-line::before {
  top: -6px;
}

.nav-toggle-line::after {
  top: 6px;
}

.site-nav {
  position: absolute;
  top: 72px;
  left: 1rem;
  right: 1rem;
  display: none;
  flex-direction: column;
  gap: var(--space-1);
  padding: var(--space-3);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-md);
}

.site-nav.is-open {
  display: flex;
}

.site-nav a {
  text-decoration: none;
  color: var(--color-muted);
  font-weight: 700;
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-sm);
  transition: color 160ms ease, background-color 160ms ease;
}

.site-nav a:hover,
.site-nav a[aria-current="page"],
.site-nav a.is-active {
  color: var(--color-primary);
  background: var(--color-soft-blue);
}

/* 6. hero */
.hero {
  padding: var(--space-7) 0 var(--space-5);
  background:
    linear-gradient(180deg, var(--color-white) 0%, rgba(247, 250, 252, 0.92) 100%),
    var(--color-background);
  border-bottom: 1px solid var(--color-border);
}

.hero-grid {
  display: grid;
  gap: var(--space-6);
  align-items: center;
}

.hero-copy {
  display: grid;
  gap: var(--space-4);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  margin-top: var(--space-2);
}

.workflow-panel {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-5);
  box-shadow: var(--shadow-md);
}

.workflow-header,
.card-meta,
.tool-detail-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: var(--space-3);
}

.panel-status,
.status-tag {
  color: var(--color-muted);
  font-size: 0.9rem;
  font-weight: 700;
}

.workflow-list {
  display: grid;
  gap: var(--space-4);
  margin-top: var(--space-5);
  padding: 0;
  list-style: none;
}

.workflow-list li,
.step-card {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: var(--space-3);
  align-items: start;
}

.step-marker {
  display: inline-grid;
  place-items: center;
  width: 2rem;
  height: 2rem;
  border-radius: 999px;
  background: var(--color-soft-blue);
  color: var(--color-primary);
  border: 1px solid var(--color-border);
  font-weight: 800;
}

/* 7. cards */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  padding: var(--space-5);
}

.tool-card,
.tool-detail,
.editorial-card,
.callout,
.placeholder-panel {
  display: grid;
  gap: var(--space-3);
}

.tool-card .button,
.tool-detail .button {
  justify-self: start;
  margin-top: var(--space-2);
}

.learn-line {
  color: var(--color-text);
}

.badge {
  display: inline-flex;
  align-items: center;
  width: fit-content;
  border: 1px solid rgba(31, 122, 140, 0.28);
  border-radius: 999px;
  background: var(--color-soft-teal);
  color: var(--color-secondary);
  font-size: 0.84rem;
  font-weight: 800;
  line-height: 1;
  padding: 0.42rem 0.65rem;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 2.75rem;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  padding: 0.72rem 1rem;
  font-weight: 800;
  text-decoration: none;
  transition: background-color 160ms ease, border-color 160ms ease, color 160ms ease;
}

.button-primary {
  background: var(--color-primary);
  color: var(--color-white);
}

.button-primary:hover {
  background: var(--color-primary-dark);
}

.button-secondary {
  background: var(--color-surface);
  border-color: var(--color-border);
  color: var(--color-primary);
}

.button-secondary:hover {
  border-color: var(--color-secondary);
  background: var(--color-soft-teal);
}

.button:disabled,
.button:disabled:hover {
  background: var(--color-soft-gray);
  border-color: var(--color-border);
  color: var(--color-muted);
}

.trust-strip {
  display: grid;
  gap: var(--space-3);
  padding: var(--space-4);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
}

.trust-strip div {
  display: grid;
  gap: var(--space-1);
}

.trust-strip span {
  color: var(--color-muted);
}

.detail-grid {
  display: grid;
  gap: var(--space-4);
}

.placeholder-panel {
  background: var(--color-soft-gold);
  border: 1px solid rgba(176, 141, 87, 0.45);
  border-radius: var(--radius-md);
  padding: var(--space-4);
}

.source-list {
  display: grid;
  gap: var(--space-2);
  color: var(--color-muted);
  padding-left: 1.25rem;
}

/* 8. forms */
.feedback-form {
  display: grid;
  gap: var(--space-4);
}

.planner-form {
  display: grid;
  gap: var(--space-4);
}

.form-grid {
  display: grid;
  gap: var(--space-4);
}

.form-field {
  display: grid;
  gap: var(--space-2);
}

.form-field label {
  color: var(--color-text);
  font-weight: 800;
}

.form-field input,
.form-field textarea,
.form-field select {
  width: 100%;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-white);
  color: var(--color-text);
  padding: 0.85rem 0.9rem;
}

.form-field select {
  min-height: 3.15rem;
}

.form-field textarea {
  resize: vertical;
}

.input-with-unit {
  display: flex;
  align-items: center;
  width: 100%;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-white);
  overflow: hidden;
}

.input-with-unit:focus-within {
  outline: 3px solid var(--color-accent);
  outline-offset: 3px;
}

.input-with-unit input {
  border: 0;
  border-radius: 0;
  min-width: 0;
}

.input-with-unit input:focus-visible {
  outline: 0;
}

.input-unit,
.unit-label {
  color: var(--color-muted);
  font-weight: 800;
  padding-inline: var(--space-3);
}

.helper-text {
  font-size: 0.94rem;
}

.field-error {
  min-height: 1.35rem;
  color: var(--color-primary);
  font-size: 0.94rem;
  font-weight: 700;
}

.error-summary {
  display: grid;
  gap: var(--space-2);
  border: 1px solid rgba(176, 141, 87, 0.45);
  border-left: 4px solid var(--color-accent);
  border-radius: var(--radius-md);
  background: var(--color-soft-gold);
  color: var(--color-text);
  padding: var(--space-4);
}

.error-summary:empty {
  display: none;
}

.error-summary ul {
  margin: 0;
  padding-left: 1.2rem;
  color: var(--color-text);
}

.form-field input[aria-invalid="true"],
.form-field select[aria-invalid="true"],
.input-with-unit.has-error {
  border-color: var(--color-accent);
}

.form-actions {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.form-message {
  min-height: 1.6rem;
  color: var(--color-primary);
  font-weight: 700;
}

.expense-group {
  display: grid;
  gap: var(--space-4);
  border-top: 1px solid var(--color-border);
  padding-top: var(--space-4);
}

.expense-group h3 {
  color: var(--color-primary);
}

.category-definition-grid {
  gap: var(--space-3);
}

.transition-card {
  display: grid;
  gap: var(--space-4);
}

/* 9. callouts */
.callout {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-left: 4px solid var(--color-secondary);
  border-radius: var(--radius-md);
  padding: var(--space-5);
}

.warning-callout {
  border-left-color: var(--color-accent);
  background: var(--color-soft-gold);
  color: var(--color-text);
  margin-top: var(--space-3);
}

.warning-callout strong {
  color: var(--color-text);
}

.notice-callout,
.feedback-callout {
  display: grid;
  gap: var(--space-3);
}

.notice-callout p {
  color: var(--color-muted);
}

.tool-layout {
  display: grid;
  gap: var(--space-5);
  align-items: start;
}

.result-panel {
  display: grid;
  gap: var(--space-4);
}

.result-grid {
  display: grid;
  gap: var(--space-3);
}

.result-card {
  display: grid;
  gap: var(--space-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-background);
  padding: var(--space-4);
}

.result-card span {
  color: var(--color-muted);
  font-size: 0.94rem;
  font-weight: 700;
}

.result-card strong {
  color: var(--color-primary);
  font-size: 1.35rem;
  font-variant-numeric: tabular-nums;
  line-height: 1.2;
}

.result-card-emphasis {
  border-left: 4px solid var(--color-secondary);
  background: var(--color-soft-teal);
}

.result-warning {
  border-left-color: var(--color-accent);
}

.assumptions-card,
.limitations-card {
  align-content: start;
}

.assumptions-card h2,
.limitations-card h2,
.feedback-callout h2 {
  font-size: 1.45rem;
}

.takeaway-card {
  background: var(--color-soft-blue);
}

.takeaway-card p,
.formula-card p {
  color: var(--color-text);
}

.insight-section,
.scenario-section,
.learning-section,
.interpretation-section {
  scroll-margin-top: 88px;
}

.interpretation-grid,
.insight-grid {
  display: grid;
  gap: var(--space-4);
}

.insight-card {
  align-content: start;
  border-left: 4px solid var(--color-secondary);
}

.insight-card p {
  color: var(--color-text);
}

.scenario-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
}

.scenario-table-wrap {
  max-width: 100%;
  overflow-x: auto;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-surface);
  box-shadow: var(--shadow-sm);
}

.scenario-table {
  width: 100%;
  min-width: 620px;
  border-collapse: collapse;
  font-variant-numeric: tabular-nums;
}

.scenario-table th,
.scenario-table td {
  padding: var(--space-3) var(--space-4);
  border-bottom: 1px solid var(--color-border);
  text-align: left;
  vertical-align: top;
}

.scenario-table th {
  color: var(--color-primary);
  background: var(--color-soft-blue);
  font-weight: 800;
}

.scenario-table tr:last-child td {
  border-bottom: 0;
}

.key-idea-callout {
  max-width: 860px;
}

/* 10. footer */
.footer {
  background: var(--color-primary);
  color: var(--color-white);
  padding: var(--space-7) 0;
}

.footer p,
.footer a {
  color: rgba(255, 255, 255, 0.82);
}

.footer strong {
  color: var(--color-white);
}

.footer-grid {
  display: grid;
  gap: var(--space-5);
}

.footer-inner {
  display: grid;
  gap: var(--space-5);
}

.footer-brand {
  color: var(--color-white);
  font-weight: 800;
}

.footer-nav {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
}

.footer-nav a {
  font-weight: 700;
}

.footer-disclaimer {
  max-width: 860px;
}

.footer-small {
  font-size: 0.92rem;
}

/* 11. responsive rules */
@media (min-width: 640px) {
  .container {
    width: min(100% - 3rem, var(--max-width));
  }

  .trust-strip,
  .form-grid,
  .detail-grid,
  .result-grid,
  .insight-grid,
  .interpretation-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .card-grid,
  .callout-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 780px) {
  body {
    font-size: 17px;
  }

  h1 {
    font-size: 3.6rem;
  }

  h2 {
    font-size: 2.35rem;
  }

  .nav-toggle {
    display: none;
  }

  .site-nav {
    position: static;
    display: flex;
    flex-direction: row;
    align-items: center;
    gap: var(--space-1);
    padding: 0;
    background: transparent;
    border: 0;
    border-radius: 0;
    box-shadow: none;
  }

  .hero-grid {
    grid-template-columns: minmax(0, 1.08fr) minmax(340px, 0.92fr);
  }

  .tool-layout {
    grid-template-columns: minmax(300px, 0.85fr) minmax(360px, 1.15fr);
  }

  .three-column,
  .step-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .step-card {
    grid-template-columns: 1fr;
  }
}

@media (min-width: 960px) {
  .section {
    padding: 5rem 0;
  }

  .hero {
    padding: 5.5rem 0 3rem;
  }

  .card-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (max-width: 420px) {
  .brand-text {
    max-width: 11rem;
    line-height: 1.2;
  }

  .brand-line {
    max-width: 12rem;
  }

  .hero-actions,
  .form-actions {
    align-items: stretch;
    flex-direction: column;
  }

  .button {
    width: 100%;
  }
}