:root {
  --background: #f6f7f7;
  --paper: #ffffff;
  --dark: #27323a;
  --text: #20272d;
  --muted: #687680;
  --line: #d5dce0;
  --surface: #e9edef;
  --max-width: 1180px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  background: var(--background);
  color: var(--text);
  font-family: Arial, Helvetica, sans-serif;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

.site-header {
  width: 100%;
  min-height: 86px;
  padding: 0 max(6%, calc((100% - var(--max-width)) / 2));
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 30px;
  border-bottom: 1px solid var(--line);
  background: rgba(246, 247, 247, 0.96);
}

.brand {
  font-size: 23px;
  font-weight: 800;
  letter-spacing: -1.2px;
  color: var(--dark);
  white-space: nowrap;
}

.brand span {
  font-weight: 400;
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 34px;
}

.main-nav a,
.header-link {
  font-size: 13px;
  font-weight: 600;
  transition: opacity 0.2s ease;
}

.main-nav a:hover,
.header-link:hover {
  opacity: 0.6;
}

.header-link {
  padding: 10px 19px;
  border: 1px solid var(--dark);
}

.hero {
  max-width: var(--max-width);
  min-height: 590px;
  margin: 0 auto;
  padding: 90px 35px;
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  align-items: center;
  gap: 70px;
}

.eyebrow {
  margin-bottom: 22px;
  color: var(--muted);
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 2px;
}

.hero h1 {
  max-width: 650px;
  font-size: clamp(42px, 5.2vw, 67px);
  line-height: 1.08;
  letter-spacing: -3px;
  font-weight: 600;
}

.hero h1 span {
  color: var(--muted);
}

.hero-description {
  max-width: 490px;
  margin: 28px 0 32px;
  color: var(--muted);
  font-size: 16px;
  line-height: 1.8;
}

.button-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 49px;
  padding: 0 23px;
  background: var(--dark);
  color: var(--paper);
  font-size: 12px;
  font-weight: 700;
  transition: background 0.2s ease, transform 0.2s ease;
}

.button-primary:hover {
  background: #3c4a54;
  transform: translateY(-2px);
}

.hero-visual {
  display: flex;
  justify-content: center;
  align-items: center;
}

.visual-frame {
  width: 100%;
  max-width: 390px;
  min-height: 390px;
  padding: 35px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  background: var(--dark);
  color: var(--paper);
  position: relative;
  overflow: hidden;
}

.visual-frame::before,
.visual-frame::after {
  content: "";
  position: absolute;
  border: 1px solid rgba(255, 255, 255, 0.13);
  border-radius: 50%;
  width: 310px;
  height: 310px;
  right: -130px;
  top: 80px;
}

.visual-frame::after {
  width: 220px;
  height: 220px;
  right: -85px;
  top: 125px;
}

.visual-label {
  font-size: 10px;
  letter-spacing: 2px;
  color: #c4cdd2;
}

.visual-mark {
  font-size: 104px;
  line-height: 1;
  font-weight: 600;
  letter-spacing: -8px;
  z-index: 1;
}

.visual-mark span {
  font-size: 35px;
  letter-spacing: 0;
}

.visual-line {
  width: 55px;
  height: 2px;
  background: #aebbc2;
  margin-bottom: 10px;
}

.visual-frame p {
  font-size: 12px;
  letter-spacing: 1px;
  color: #c4cdd2;
}

.intro {
  padding: 105px 25px;
  background: var(--paper);
  text-align: center;
}

.intro h2,
.section-heading h2,
.methodology h2,
.contact h2 {
  max-width: 750px;
  margin: 0 auto;
  font-size: clamp(30px, 4vw, 43px);
  line-height: 1.2;
  font-weight: 600;
  letter-spacing: -1.5px;
}

.intro > p:last-child {
  max-width: 650px;
  margin: 25px auto 0;
  color: var(--muted);
  font-size: 15px;
}

.audit-areas {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 110px 35px;
}

.section-heading {
  margin-bottom: 45px;
}

.section-heading h2 {
  margin: 0;
}

.areas-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 15px;
}

.area-card {
  min-height: 215px;
  padding: 28px;
  border: 1px solid var(--line);
  background: var(--paper);
  transition: transform 0.2s ease, border-color 0.2s ease;
}

.area-card:hover {
  transform: translateY(-4px);
  border-color: var(--muted);
}

.area-card > span,
.method-grid article > span {
  color: var(--muted);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 1px;
}

.area-card h3 {
  margin: 25px 0 10px;
  font-size: 18px;
  line-height: 1.3;
  font-weight: 600;
}

.area-card p,
.method-grid p {
  color: var(--muted);
  font-size: 13px;
  line-height: 1.7;
}

.methodology {
  padding: 105px max(6%, calc((100% - var(--max-width)) / 2));
  background: var(--surface);
}

.methodology h2 {
  margin: 0 0 55px;
}

.method-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 30px;
}

.method-grid article {
  padding-top: 20px;
  border-top: 1px solid #bac4ca;
}

.method-grid h3 {
  margin: 20px 0 10px;
  font-size: 18px;
  font-weight: 600;
}

.contact {
  padding: 110px 25px;
  background: var(--paper);
  text-align: center;
}

.contact > p:not(.eyebrow) {
  margin: 22px auto 28px;
  color: var(--muted);
  font-size: 14px;
}

.site-footer {
  min-height: 130px;
  padding: 35px max(6%, calc((100% - var(--max-width)) / 2));
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 25px;
  border-top: 1px solid var(--line);
}

.site-footer p {
  color: var(--muted);
  font-size: 11px;
}

@media (max-width: 850px) {
  .site-header {
    padding: 20px 5%;
    flex-wrap: wrap;
  }

  .main-nav {
    order: 3;
    width: 100%;
    justify-content: center;
    gap: 22px;
  }

  .hero {
    grid-template-columns: 1fr;
    gap: 55px;
    padding: 75px 7%;
  }

  .hero-visual {
    justify-content: flex-start;
  }

  .visual-frame {
    max-width: 100%;
    min-height: 310px;
  }

  .areas-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .method-grid {
    grid-template-columns: repeat(2, 1fr);
    row-gap: 40px;
  }

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

@media (max-width: 520px) {
  .site-header {
    min-height: auto;
    gap: 15px;
  }

  .brand {
    font-size: 21px;
  }

  .main-nav {
    justify-content: flex-start;
    gap: 17px;
    overflow-x: auto;
  }

  .main-nav a {
    font-size: 11px;
    white-space: nowrap;
  }

  .header-link {
    padding: 8px 12px;
    font-size: 11px;
  }

  .hero {
    padding: 65px 6%;
  }

  .hero h1 {
    font-size: 43px;
    letter-spacing: -2px;
  }

  .hero-description {
    font-size: 14px;
  }

  .visual-frame {
    min-height: 270px;
    padding: 27px;
  }

  .visual-mark {
    font-size: 82px;
  }

  .intro,
  .audit-areas,
  .methodology,
  .contact {
    padding-top: 75px;
    padding-bottom: 75px;
  }

  .areas-grid,
  .method-grid {
    grid-template-columns: 1fr;
  }

  .area-card {
    min-height: 175px;
  }

  .intro h2,
  .section-heading h2,
  .methodology h2,
  .contact h2 {
    font-size: 32px;
  }

  .site-footer {
    align-items: flex-start;
    flex-direction: column;
    gap: 12px;
  }
}