:root {
  --color-bg: #f7f8fc;
  --color-surface: #ffffff;
  --color-surface-2: #f1f2f9;
  --color-bg-accent: #eef0fd;
  --color-text: #1a1d29;
  --color-muted: #5b6072;
  --color-text-muted: #9498ab;
  --color-text-accent: #4338ca;
  --color-border: #e4e6ef;
  --color-primary: #4f46e5;
  --color-primary-dark: #4338ca;
  --color-accent: #06b6d4;
  --color-success: #16a34a;
  --radius: 14px;
  --radius-sm: 10px;
  --radius-pill: 999px;
  --shadow: 0 1px 2px rgba(20, 22, 40, 0.04);
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
}

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

a {
  color: var(--color-primary);
}

.container {
  width: 100%;
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 20px;
}

.site-header {
  border-bottom: 0.5px solid var(--color-border);
  background: var(--color-surface);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 16px;
  padding-bottom: 16px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  font-size: 1.15rem;
  text-decoration: none;
  color: var(--color-text);
}

.brand svg {
  flex-shrink: 0;
}

.main-nav {
  display: flex;
  gap: 8px;
  overflow-x: auto;
}

.main-nav a {
  font-weight: 600;
  text-decoration: none;
  font-size: 0.85rem;
  color: var(--color-muted);
  padding: 6px 14px;
  border-radius: var(--radius-pill);
  border: 0.5px solid var(--color-border);
  white-space: nowrap;
}

.main-nav a:hover {
  color: var(--color-primary);
}

.main-nav a[aria-current="page"] {
  background: var(--color-bg-accent);
  color: var(--color-text-accent);
  border-color: transparent;
  font-weight: 700;
}

.header-controls {
  display: flex;
  align-items: center;
  gap: 20px;
}

.currency-select {
  padding: 8px 10px;
  border: 0.5px solid var(--color-border);
  border-radius: 8px;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: inherit;
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
}

.currency-select:focus {
  outline: 2px solid var(--color-primary);
  outline-offset: 1px;
}

.hero {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-accent) 100%);
  color: #fff;
  padding: 56px 0 64px;
}

.hero h1 {
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  margin: 0 0 12px;
}

.hero p {
  max-width: 640px;
  margin: 0;
  font-size: 1.05rem;
  opacity: 0.95;
}

.content {
  padding: 40px 0 64px;
}

.calculator-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 24px;
}

@media (min-width: 800px) {
  .calculator-grid {
    grid-template-columns: minmax(0, 380px) minmax(0, 1fr);
    align-items: start;
  }
}

.card {
  background: var(--color-surface);
  border: 0.5px solid var(--color-border);
  border-radius: var(--radius);
  padding: 24px;
}

.card h2 {
  margin-top: 0;
  font-size: 1.1rem;
  display: flex;
  align-items: center;
  gap: 8px;
}

.card h2 svg {
  flex-shrink: 0;
  color: var(--color-primary);
}

.field {
  margin-bottom: 20px;
}

.field label {
  display: block;
  font-weight: 600;
  font-size: 0.9rem;
  margin-bottom: 6px;
}

.field .hint {
  font-size: 0.8rem;
  color: var(--color-muted);
  font-weight: 400;
}

.field input[type="number"],
.field input[type="text"],
.field select,
.field textarea {
  width: 100%;
  padding: 12px 14px;
  border: 0.5px solid var(--color-border);
  border-radius: 10px;
  font-size: 1rem;
  font-family: inherit;
  background: var(--color-bg);
  color: var(--color-text);
}

.field textarea {
  resize: vertical;
  min-height: 90px;
}

.field input[type="number"]:focus,
.field input[type="text"]:focus,
.field select:focus,
.field textarea:focus {
  outline: 2px solid var(--color-primary);
  outline-offset: 1px;
}

.tenure-row {
  display: flex;
  gap: 10px;
}

.tenure-row input {
  flex: 1;
}

.unit-toggle {
  display: flex;
  border: 0.5px solid var(--color-border);
  border-radius: 10px;
  overflow: hidden;
  flex-shrink: 0;
}

.converter-row {
  display: flex;
  align-items: center;
  gap: 10px;
}

.converter-row .field {
  flex: 1;
  margin-bottom: 0;
}

.btn-icon {
  flex-shrink: 0;
  width: 40px;
  height: 40px;
  margin-top: 22px;
  border: 0.5px solid var(--color-border);
  border-radius: 50%;
  background: var(--color-bg);
  color: var(--color-primary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
}

.btn-icon:hover {
  background: var(--color-bg-accent);
}

.gpa-rows,
.data-rows {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 16px;
}

.gpa-row,
.data-row {
  display: flex;
  align-items: center;
  gap: 8px;
}

.gpa-row select {
  flex: 2;
  padding: 10px 12px;
  border: 0.5px solid var(--color-border);
  border-radius: 10px;
  font-family: inherit;
  font-size: 0.95rem;
  background: var(--color-bg);
  color: var(--color-text);
}

.gpa-row input,
.data-row input {
  flex: 1;
  padding: 10px 12px;
  border: 0.5px solid var(--color-border);
  border-radius: 10px;
  font-family: inherit;
  font-size: 0.95rem;
  background: var(--color-bg);
  color: var(--color-text);
}

.gpa-row .btn-icon,
.data-row .btn-icon {
  width: 32px;
  height: 32px;
  margin-top: 0;
  font-size: 1.1rem;
  line-height: 1;
}

.btn-secondary {
  width: 100%;
  padding: 10px 16px;
  border: 0.5px dashed var(--color-border);
  border-radius: 10px;
  background: transparent;
  color: var(--color-primary);
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  font-family: inherit;
  margin-bottom: 20px;
}

.btn-secondary:hover {
  background: var(--color-bg-accent);
}

.unit-toggle button {
  border: none;
  background: var(--color-bg);
  padding: 0 16px;
  font-family: inherit;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--color-muted);
  cursor: pointer;
}

.unit-toggle button[aria-pressed="true"] {
  background: var(--color-primary);
  color: #fff;
}

.btn-primary {
  width: 100%;
  padding: 14px 18px;
  border: none;
  border-radius: 10px;
  background: var(--color-primary);
  color: #fff;
  font-size: 1rem;
  font-weight: 700;
  cursor: pointer;
  font-family: inherit;
}

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

.error-message {
  color: #b91c1c;
  font-size: 0.85rem;
  margin-top: 10px;
  min-height: 1.2em;
}

.results {
  display: none;
}

.results.is-visible {
  display: block;
}

.result-summary {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 16px;
  margin-bottom: 24px;
}

.result-headline {
  background: var(--color-bg-accent);
  border-radius: var(--radius);
  padding: 20px;
  margin-bottom: 20px;
}

.result-headline .label {
  font-size: 0.85rem;
  color: var(--color-text-accent);
  font-weight: 600;
}

.result-headline .value {
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-text-accent);
  margin-top: 4px;
}

.result-breakdown {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 20px;
}

.result-breakdown .row {
  display: flex;
  justify-content: space-between;
  font-size: 0.9rem;
  padding: 6px 0;
  border-bottom: 0.5px solid var(--color-border);
}

.result-breakdown .row span:first-child {
  color: var(--color-muted);
}

.result-breakdown .row span:last-child {
  font-weight: 600;
}

.result-stat {
  background: var(--color-surface-2);
  border: 0.5px solid var(--color-border);
  border-radius: 10px;
  padding: 16px;
}

.result-stat .label {
  font-size: 0.8rem;
  color: var(--color-muted);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

.result-stat .value {
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--color-primary-dark);
  margin-top: 4px;
}

.schedule-wrap {
  max-height: 340px;
  overflow: auto;
  border: 0.5px solid var(--color-border);
  border-radius: 10px;
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.88rem;
}

thead th {
  position: sticky;
  top: 0;
  background: var(--color-surface);
  text-align: right;
  padding: 10px 12px;
  border-bottom: 0.5px solid var(--color-border);
}

thead th:first-child,
tbody td:first-child {
  text-align: left;
}

tbody td {
  padding: 8px 12px;
  text-align: right;
  border-bottom: 0.5px solid var(--color-border);
}

.info-section {
  margin-top: 48px;
}

.info-section h2 {
  font-size: 1.4rem;
}

.faq-item {
  border-bottom: 0.5px solid var(--color-border);
  padding: 16px 0;
}

.faq-item h3 {
  margin: 0 0 8px;
  font-size: 1rem;
}

.faq-item p {
  margin: 0;
  color: var(--color-muted);
}

.site-footer {
  border-top: 0.5px solid var(--color-border);
  padding: 24px 0;
  text-align: center;
  color: var(--color-muted);
  font-size: 0.85rem;
}

.tool-card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 12px;
  margin-top: 16px;
}

.tool-card {
  background: var(--color-surface-2);
  border: 0.5px solid var(--color-border);
  border-radius: var(--radius);
  padding: 18px 14px;
  text-decoration: none;
  color: var(--color-text);
  text-align: center;
  transition: border-color 0.15s ease, transform 0.15s ease;
}

.tool-card:hover {
  border-color: var(--color-primary);
  transform: translateY(-2px);
}

.tool-card svg {
  color: var(--color-primary);
  margin: 0 auto 8px;
}

.tool-card h2 {
  margin: 0;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--color-text);
}

.ad-slot {
  background: var(--color-surface-2);
  border-radius: var(--radius-sm);
  padding: 14px;
  text-align: center;
  color: var(--color-text-muted);
  font-size: 0.75rem;
  margin: 20px 0;
}

.ad-slot.banner {
  padding: 20px;
}

h2.section-label {
  font-size: 0.85rem;
  color: var(--color-muted);
  margin: 32px 0 0;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

.hub-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
  align-items: start;
}

@media (min-width: 800px) {
  .hub-grid {
    grid-template-columns: minmax(0, 1fr) 160px;
  }
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

.calc-display {
  font-size: 1.6rem;
  font-weight: 700;
  text-align: right;
  padding: 16px;
  background: var(--color-bg);
  border: 0.5px solid var(--color-border);
  border-radius: 10px;
  margin-bottom: 12px;
  min-height: 1.5em;
  word-break: break-all;
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
}

.calc-error {
  color: #b91c1c;
  font-size: 0.85rem;
  min-height: 1.2em;
  margin: 8px 0 0;
}

.calc-keypad {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 8px;
}

.calc-keypad button {
  padding: 14px 0;
  border: 0.5px solid var(--color-border);
  border-radius: 10px;
  background: var(--color-surface-2);
  color: var(--color-text);
  font-family: inherit;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
}

.calc-keypad button:hover {
  background: var(--color-bg-accent);
}

.calc-keypad button[data-calc-key="equals"] {
  background: var(--color-primary);
  color: #fff;
  grid-column: span 2;
}

.calc-keypad button[data-calc-key="clear"] {
  color: #b91c1c;
}

.graph-svg-wrap {
  background: var(--color-surface-2);
  border: 0.5px solid var(--color-border);
  border-radius: var(--radius);
  padding: 12px;
  margin-top: 16px;
}

.graph-svg-wrap svg {
  width: 100%;
  height: auto;
  display: block;
}