:root {
  --color-bg: #f5f7fb;
  --color-surface: #ffffff;
  --color-surface-soft: #f0f4fa;
  --color-text: #12233f;
  --color-muted: #4f607b;
  --color-border: #d8e1ef;
  --color-primary: #2c5dd8;
  --color-primary-strong: #224ab0;
  --color-success: #11753f;
  --color-danger: #b42318;
  --radius-sm: 10px;
  --radius-md: 14px;
  --radius-lg: 18px;
  --shadow-soft: 0 8px 24px rgba(18, 35, 63, 0.07);
  --shadow-card: 0 10px 30px rgba(18, 35, 63, 0.08);
  --space-2xs: 0.25rem;
  --space-xs: 0.5rem;
  --space-sm: 0.75rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2.25rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  --container-max: 1120px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: Inter, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-text);
  background: var(--color-bg);
  text-rendering: optimizeLegibility;
}

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

a {
  color: var(--color-primary);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

h1,
h2,
h3,
h4 {
  margin: 0 0 var(--space-sm);
  line-height: 1.25;
  color: var(--color-text);
}

h1 {
  font-size: clamp(1.95rem, 3.9vw, 2.7rem);
}

h2 {
  font-size: clamp(1.45rem, 3vw, 2rem);
}

h3 {
  font-size: clamp(1.1rem, 2.2vw, 1.3rem);
}

p {
  margin: 0 0 var(--space-md);
}

ul {
  margin: 0;
  padding: 0;
}

.container {
  width: min(var(--container-max), 92%);
  margin-inline: auto;
}

.section {
  padding-block: var(--space-2xl);
}

.section-header {
  margin-bottom: var(--space-lg);
}

.section-intro {
  color: var(--color-muted);
  max-width: 760px;
}

.surface {
  background: var(--color-surface-soft);
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.u-text-muted {
  color: var(--color-muted);
}

.u-shadow-soft {
  box-shadow: var(--shadow-soft);
}

.u-rounded-md {
  border-radius: var(--radius-md);
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  padding-block: 0.85rem;
}

.site-logo {
  font-size: 1.3rem;
  font-weight: 800;
  letter-spacing: 0.2px;
  color: var(--color-text);
}

.site-logo:hover {
  text-decoration: none;
}

.menu-toggle {
  display: none;
  border: 1px solid var(--color-border);
  background: var(--color-surface);
  color: var(--color-text);
  border-radius: var(--radius-sm);
  padding: 0.45rem 0.85rem;
  font: inherit;
  font-weight: 600;
  cursor: pointer;
}

.menu-toggle:hover {
  background: #f8fbff;
}

.nav-primary__list {
  list-style: none;
  display: flex;
  align-items: center;
  gap: 0.95rem;
  flex-wrap: wrap;
}

.nav-primary__link {
  display: inline-block;
  color: var(--color-text);
  font-weight: 600;
  font-size: 0.95rem;
  padding: 0.35rem 0.15rem;
  border-bottom: 2px solid transparent;
}

.nav-primary__link[aria-current="page"] {
  border-bottom-color: var(--color-primary);
  color: var(--color-primary-strong);
}

.nav-primary__link:hover {
  text-decoration: none;
  color: var(--color-primary-strong);
}

.hero {
  padding-block: var(--space-3xl) var(--space-2xl);
}

.home-hero__inner {
  max-width: 860px;
}

.home-hero__eyebrow {
  margin: 0 0 var(--space-xs);
  font-size: 0.82rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-primary-strong);
}

.home-hero__title {
  margin-bottom: var(--space-sm);
}

.home-hero__lead {
  color: var(--color-muted);
  max-width: 760px;
  margin-bottom: 0;
}

.home-hero__actions {
  margin-top: var(--space-lg);
  display: flex;
  gap: var(--space-sm);
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0.68rem 1.05rem;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  font-weight: 700;
  font-size: 0.95rem;
  text-decoration: none;
  transition: background-color 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}

.btn:hover {
  text-decoration: none;
}

.btn-primary {
  color: #fff;
  background: var(--color-primary);
  border-color: var(--color-primary);
}

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

.btn-secondary {
  color: var(--color-text);
  background: var(--color-surface);
  border-color: var(--color-border);
}

.btn-secondary:hover {
  background: #f8fbff;
}

.calculator-hub__grid,
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: var(--space-md);
}

.calculator-card,
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-card);
  padding: var(--space-md);
}

.calculator-card__title {
  margin-bottom: var(--space-xs);
}

.calculator-card__text {
  color: var(--color-muted);
  margin-bottom: var(--space-md);
}

.calculator-card__link {
  font-weight: 700;
}

.home-info__inner {
  display: grid;
  gap: var(--space-lg);
}

.feature-list,
.home-info__list {
  list-style: none;
  display: grid;
  gap: var(--space-sm);
}

.home-info__item {
  position: relative;
  padding-left: 1.15rem;
}

.home-info__item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.65rem;
  width: 0.46rem;
  height: 0.46rem;
  border-radius: 50%;
  background: #9db2d8;
}

.ad-slot {
  border: 1px dashed #9fb0ca;
  border-radius: var(--radius-md);
  min-height: 120px;
  display: grid;
  place-items: center;
  text-align: center;
  background: #f7faff;
  color: var(--color-muted);
}

.site-footer {
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
}

.site-footer__inner {
  padding-block: 1rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-md);
  flex-wrap: wrap;
}

.site-footer__copy {
  margin: 0;
  color: var(--color-muted);
}

.footer-nav__list {
  list-style: none;
  display: flex;
  align-items: center;
  gap: var(--space-md);
  flex-wrap: wrap;
}

.footer-nav__link {
  color: var(--color-text);
  font-weight: 600;
  font-size: 0.92rem;
}

.page-hero {
  padding: var(--space-xl) 0 var(--space-md);
}

.page-hero p {
  max-width: 760px;
  color: var(--color-muted);
}

.calculator-box,
.content-box {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-card);
  padding: 1.2rem;
}

.form-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: var(--space-md);
}

label {
  display: block;
  margin-bottom: var(--space-xs);
  font-weight: 600;
}

input,
select,
textarea {
  width: 100%;
  border: 1px solid #b9c8df;
  border-radius: var(--radius-sm);
  background: #fff;
  color: var(--color-text);
  padding: 0.62rem 0.72rem;
  font: inherit;
}

input:focus,
select:focus,
textarea:focus {
  outline: 2px solid rgba(44, 93, 216, 0.18);
  border-color: var(--color-primary);
}

textarea {
  min-height: 130px;
  resize: vertical;
}

.result {
  margin-top: var(--space-md);
  padding: 0.85rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: #f8fbff;
}

.result strong {
  font-size: 1.08rem;
}

.status-ok {
  color: var(--color-success);
}

.status-error {
  color: var(--color-danger);
}

@media (max-width: 1024px) {
  .hero {
    padding-block: var(--space-2xl) var(--space-xl);
  }
}

@media (max-width: 840px) {
  .menu-toggle {
    display: inline-flex;
  }

  .main-nav {
    display: none;
    width: 100%;
  }

  .main-nav.is-open {
    display: block;
  }

  .site-header__inner {
    flex-wrap: wrap;
  }

  .nav-primary__list {
    width: 100%;
    flex-direction: column;
    align-items: flex-start;
    gap: 0.6rem;
    border-top: 1px solid var(--color-border);
    padding-top: var(--space-sm);
  }

  .nav-primary__link {
    width: 100%;
    padding: 0.4rem 0;
    border-bottom: none;
  }

  .section {
    padding-block: var(--space-xl);
  }
}

@media (max-width: 640px) {
  body {
    font-size: 15.5px;
  }

  .container {
    width: min(var(--container-max), 94%);
  }

  .home-hero__actions {
    flex-direction: column;
    align-items: stretch;
  }

  .btn {
    width: 100%;
  }

  .site-footer__inner {
    align-items: flex-start;
  }
}