:root {
  color-scheme: light;
  --font-sans: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --color-primary: #1f5f8b;
  --color-primary-dark: #174966;
  --color-secondary: #00a896;
  --color-background: #f7fbff;
  --color-surface: #ffffff;
  --color-text: #0f172a;
  --color-muted: #475569;
  --shadow-medium: 0 20px 45px rgba(15, 23, 42, 0.15);
  --radius-large: 24px;
  --radius-medium: 16px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  color: var(--color-text);
  background: linear-gradient(180deg, rgba(247, 251, 255, 0.9) 0%, rgba(255, 255, 255, 1) 60%);
}

a {
  color: inherit;
  text-decoration: none;
}

a:hover,
a:focus {
  text-decoration: underline;
}

img {
  max-width: 100%;
  height: auto;
}

.container {
  width: min(1100px, 90vw);
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid rgba(15, 23, 42, 0.05);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 0;
}

.logo {
  font-weight: 700;
  font-size: 1.25rem;
  letter-spacing: 0.03em;
}

.nav-list {
  display: flex;
  gap: 1rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-list a {
  font-weight: 600;
  color: var(--color-muted);
  padding: 0.5rem 0.75rem;
  border-radius: 999px;
  transition: background-color 150ms ease, color 150ms ease;
}

.nav-list a:hover,
.nav-list a:focus {
  color: var(--color-primary);
  background: rgba(31, 95, 139, 0.08);
}

.hero {
  padding: 6rem 0 5rem;
}

.hero__content {
  display: grid;
  gap: 3rem;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  align-items: center;
}

.hero__text h1 {
  font-size: clamp(2.5rem, 5vw, 3.5rem);
  margin-bottom: 1rem;
}

.hero__text p {
  font-size: 1.1rem;
  color: var(--color-muted);
  max-width: 50ch;
}

.hero__figure {
  min-height: 320px;
  border-radius: var(--radius-large);
  background: radial-gradient(circle at top right, rgba(0, 168, 150, 0.3), transparent 55%),
    linear-gradient(135deg, rgba(31, 95, 139, 0.8), rgba(31, 95, 139, 0.35));
  position: relative;
  overflow: hidden;
  box-shadow: var(--shadow-medium);
}

.hero__figure::after {
  content: '';
  position: absolute;
  inset: 20%;
  border: 2px dashed rgba(255, 255, 255, 0.6);
  border-radius: var(--radius-medium);
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 999px;
  padding: 0.85rem 1.8rem;
  font-weight: 600;
  transition: transform 150ms ease, box-shadow 150ms ease, background 150ms ease;
}

.button--primary {
  background: var(--color-primary);
  color: white;
  box-shadow: 0 15px 30px rgba(31, 95, 139, 0.35);
}

.button--primary:hover,
.button--primary:focus {
  transform: translateY(-2px);
  box-shadow: 0 20px 35px rgba(31, 95, 139, 0.45);
}

.button--secondary {
  background: white;
  color: var(--color-primary);
  border: 1px solid rgba(31, 95, 139, 0.2);
  margin-left: 0.75rem;
}

.section {
  padding: 4.5rem 0;
}

.section--alt {
  background: var(--color-background);
}

.section__grid {
  display: grid;
  gap: 2.5rem;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  align-items: start;
}

.section__grid--three {
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

.section h2 {
  font-size: clamp(2rem, 3vw, 2.5rem);
  margin-bottom: 1.5rem;
}

.section p {
  color: var(--color-muted);
  line-height: 1.6;
}

.calculator {
  display: grid;
  gap: 1.25rem;
  background: white;
  padding: 2.5rem;
  border-radius: var(--radius-medium);
  box-shadow: var(--shadow-medium);
}

.form-row {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

label {
  font-weight: 600;
}

input,
select {
  padding: 0.75rem 1rem;
  border-radius: 12px;
  border: 1px solid rgba(15, 23, 42, 0.1);
  font: inherit;
  transition: border-color 150ms ease, box-shadow 150ms ease;
}

input:focus,
select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 4px rgba(31, 95, 139, 0.15);
}

.form-actions {
  display: flex;
  justify-content: flex-start;
  margin-top: 1rem;
}

.calculator__note {
  font-size: 0.875rem;
  color: var(--color-muted);
  margin: 0;
}

.results {
  margin-top: 3rem;
  display: grid;
  gap: 1rem;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

.results h3 {
  grid-column: 1 / -1;
  margin: 0;
}

.results dl {
  margin: 0;
  display: contents;
}

.results div {
  background: white;
  border-radius: 18px;
  padding: 1.5rem;
  box-shadow: 0 12px 30px rgba(15, 23, 42, 0.12);
}

.results dt {
  font-weight: 600;
  color: var(--color-muted);
}

.results dd {
  margin: 0.5rem 0 0;
  font-size: 1.5rem;
  font-weight: 700;
}

.steps {
  list-style: none;
  counter-reset: steps;
  display: grid;
  gap: 1.25rem;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  margin: 0;
  padding: 0;
}

.steps li {
  position: relative;
  background: white;
  padding: 1.75rem;
  border-radius: var(--radius-medium);
  box-shadow: 0 15px 28px rgba(15, 23, 42, 0.1);
  font-weight: 600;
  line-height: 1.5;
}

.steps__number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--color-primary);
  color: white;
  font-weight: 700;
  margin-right: 0.75rem;
}

details {
  background: white;
  border-radius: var(--radius-medium);
  margin-bottom: 1rem;
  padding: 1.25rem 1.5rem;
  box-shadow: 0 15px 25px rgba(15, 23, 42, 0.1);
}

details[open] summary {
  color: var(--color-primary);
}

summary {
  cursor: pointer;
  font-weight: 600;
}

summary::-webkit-details-marker {
  display: none;
}

.site-footer {
  background: #0f172a;
  color: rgba(255, 255, 255, 0.8);
  padding: 2.5rem 0;
  margin-top: 3rem;
}

.site-footer a {
  color: rgba(255, 255, 255, 0.85);
}

.site-footer .container {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

@media (max-width: 640px) {
  .nav-list {
    display: none;
  }

  .button--secondary {
    margin-left: 0;
    margin-top: 0.75rem;
  }

  .cta-group {
    display: flex;
    flex-direction: column;
    align-items: stretch;
    gap: 0.75rem;
  }

  .calculator {
    padding: 1.75rem;
  }
}