* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: Arial, Helvetica, sans-serif;
  color: #172033;
  background: #f6f8fb;
  line-height: 1.6;
}

.container {
  width: min(1120px, calc(100% - 40px));
  margin: 0 auto;
}

.site-header {
  background: #ffffff;
  border-bottom: 1px solid #e8edf3;
}

.header-inner {
  min-height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.brand {
  font-size: 1.35rem;
  font-weight: 800;
  letter-spacing: .08em;
}

.brand span {
  font-weight: 500;
}

.tagline {
  color: #687386;
  font-size: .9rem;
}

.hero {
  padding: 72px 0 52px;
  background: #ffffff;
}

.eyebrow {
  color: #61708a;
  font-size: .76rem;
  font-weight: 800;
  letter-spacing: .14em;
  margin-bottom: 10px;
}

.hero h1 {
  font-size: clamp(2rem, 5vw, 3.35rem);
  line-height: 1.08;
  max-width: 760px;
  margin-bottom: 18px;
}

.hero-text {
  color: #687386;
  font-size: 1.08rem;
  max-width: 680px;
}

.calculator-section {
  padding: 48px 0 0;
}

.calculator-card {
  background: #ffffff;
  border: 1px solid #e8edf3;
  border-radius: 18px;
  padding: 34px;
  box-shadow: 0 12px 35px rgba(23, 32, 51, .06);
}

.card-heading {
  margin-bottom: 28px;
}

.card-heading h2 {
  font-size: 1.65rem;
  margin-bottom: 6px;
}

.card-heading p {
  color: #687386;
}

.form-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 22px;
}

.form-group label {
  display: block;
  font-size: .9rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.form-group input {
  width: 100%;
  height: 50px;
  padding: 0 14px;
  border: 1px solid #ccd5e2;
  border-radius: 10px;
  font: inherit;
  color: #172033;
  background: #ffffff;
}

.form-group input:focus {
  outline: none;
  border-color: #718096;
  box-shadow: 0 0 0 3px rgba(113, 128, 150, .12);
}

.error-message {
  display: block;
  min-height: 22px;
  padding-top: 5px;
  color: #b42318;
  font-size: .78rem;
}

.input-note {
  margin: 4px 0 12px;
  color: #687386;
  font-size: .82rem;
}

button {
  width: 100%;
  min-height: 52px;
  margin-top: 8px;
  border: 0;
  border-radius: 10px;
  background: #172033;
  color: #ffffff;
  font: inherit;
  font-weight: 700;
  cursor: pointer;
  transition: transform .15s ease, opacity .15s ease;
}

button:hover {
  opacity: .92;
}

button:active {
  transform: translateY(1px);
}

.results {
  margin-top: 34px;
}

.hidden {
  display: none;
}

.result-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
}

.result-card {
  padding: 20px;
  border: 1px solid #e8edf3;
  border-radius: 12px;
  background: #f8fafc;
}

.result-card.primary {
  background: #eef2f7;
}

.result-label {
  display: block;
  color: #687386;
  font-size: .78rem;
  font-weight: 700;
  margin-bottom: 6px;
}

.result-card strong {
  display: block;
  font-size: 1.3rem;
}

.result-summary {
  margin-top: 16px;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  border: 1px solid #e8edf3;
  border-radius: 12px;
  overflow: hidden;
}

.result-summary div {
  padding: 16px;
  background: #ffffff;
  border-right: 1px solid #e8edf3;
}

.result-summary div:last-child {
  border-right: 0;
}

.result-summary span {
  display: block;
  color: #687386;
  font-size: .76rem;
  margin-bottom: 4px;
}

.result-summary strong {
  font-size: .96rem;
}

.secondary-button {
  background: #ffffff;
  color: #172033;
  border: 1px solid #ccd5e2;
  margin-top: 22px;
}

.info-section {
  margin-top: 70px;
  background: #ffffff;
  padding-top: 85px;
  padding-bottom: 70px;
  border-top: 1px solid #e8edf3;
}

.info-grid {
  display: grid;
  grid-template-columns: 1.1fr .9fr;
  gap: 60px;
  align-items: start;
}

.info-grid h2 {
  font-size: 2rem;
  line-height: 1.2;
  margin-bottom: 16px;
}

.info-grid p {
  color: #687386;
}

.formula-box {
  padding: 24px;
  background: #f6f8fb;
  border: 1px solid #e8edf3;
  border-radius: 14px;
}

.formula-box h3 {
  margin-bottom: 12px;
}

.formula-box p + p {
  margin-top: 10px;
}

.more-tools {
  padding: 65px 0;
  background: #f6f8fb;
}

.more-tools h2 {
  font-size: 1.9rem;
  margin-bottom: 10px;
}

.more-tools p:last-child {
  color: #687386;
}

.site-footer {
  padding: 28px 0;
  background: #172033;
  color: #dbe2ec;
  font-size: .86rem;
}

@media (max-width: 680px) {
  .container {
    width: min(100% - 28px, 1120px);
  }

  .header-inner {
    min-height: 64px;
    align-items: flex-start;
    flex-direction: column;
    justify-content: center;
    gap: 2px;
  }

  .tagline {
    font-size: .78rem;
  }

  .hero {
    padding: 52px 0 38px;
  }

  .calculator-card {
    padding: 22px;
    border-radius: 14px;
  }

  .form-grid,
  .result-grid,
  .result-summary {
    grid-template-columns: 1fr;
  }

  .result-summary div {
    border-right: 0;
    border-bottom: 1px solid #e8edf3;
  }

  .result-summary div:last-child {
    border-bottom: 0;
  }

  .info-section {
    margin-top: 55px;
    padding-top: 55px;
    padding-bottom: 60px;
  }

  .info-grid {
    grid-template-columns: 1fr;
    gap: 35px;
  }

  .more-tools {
    padding: 52px 0;
  }
}