:root {
  --bg: #f5f7fa;
  --surface: #ffffff;
  --surface-soft: #edf6f3;
  --text: #17202a;
  --muted: #596775;
  --line: #d9e2ea;
  --accent: #0f766e;
  --accent-dark: #115e59;
  --accent-soft: #dff4ef;
  --warning: #946200;
  --danger: #b42318;
  --shadow: 0 18px 44px rgba(23, 32, 42, 0.08);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 16px;
  line-height: 1.6;
}

a {
  color: inherit;
}

code {
  padding: 2px 6px;
  border-radius: 6px;
  background: #e8edf2;
  font-size: 0.95em;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(255, 255, 255, 0.96);
  border-bottom: 1px solid var(--line);
}

.nav {
  width: min(1120px, calc(100% - 32px));
  min-height: 72px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.logo,
.nav-link,
.footer-links a {
  text-decoration: none;
}

.logo {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
  font-size: 1.05rem;
  font-weight: 800;
}

.logo-mark {
  display: inline-grid;
  width: 36px;
  height: 36px;
  place-items: center;
  border-radius: 8px;
  background: var(--accent);
  color: #ffffff;
  font-size: 0.78rem;
  letter-spacing: 0;
}

.nav-links,
.footer-links {
  display: flex;
  align-items: center;
  gap: 20px;
  flex-wrap: wrap;
}

.nav-link,
.footer-links a {
  color: var(--muted);
  font-weight: 700;
}

.nav-link:hover,
.logo:hover,
.footer-links a:hover {
  color: var(--accent);
}

.hero {
  min-height: 520px;
  display: grid;
  align-items: center;
  background:
    linear-gradient(90deg, rgba(245, 247, 250, 0.98), rgba(245, 247, 250, 0.82)),
    url("https://images.unsplash.com/photo-1516321318423-f06f85e504b3?auto=format&fit=crop&w=1600&q=80") center / cover;
}

.hero-content,
.page-intro,
.section,
.calculator {
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto;
}

.hero-content {
  padding: 88px 0;
}

.eyebrow {
  margin: 0 0 10px;
  color: var(--accent);
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0;
  text-transform: uppercase;
}

h1,
h2,
h3 {
  margin: 0;
  line-height: 1.16;
}

h1 {
  max-width: 820px;
  font-size: clamp(2.3rem, 6vw, 4.25rem);
}

.page-intro h1 {
  max-width: 760px;
  font-size: clamp(2rem, 4vw, 3rem);
}

h2 {
  font-size: clamp(1.55rem, 3vw, 2.35rem);
}

h3 {
  font-size: 1.12rem;
}

p {
  margin: 0;
}

.hero-text,
.section-heading p,
.page-intro p,
.calculator-copy p,
.text-section p,
.faq-section p,
.point p,
.status-card p {
  max-width: 740px;
  color: var(--muted);
}

.hero-text {
  margin-top: 18px;
  font-size: 1.16rem;
}

.hero-actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 30px;
}

.primary-button,
.secondary-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 0 22px;
  border-radius: 8px;
  font: inherit;
  font-weight: 800;
  text-decoration: none;
}

.primary-button {
  border: 0;
  background: var(--accent);
  color: #ffffff;
  cursor: pointer;
}

.primary-button:hover {
  background: var(--accent-dark);
}

.secondary-button {
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.78);
  color: var(--text);
}

.secondary-button:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.section {
  padding: 76px 0;
}

.section-heading {
  display: grid;
  gap: 12px;
  margin-bottom: 30px;
}

.tool-grid,
.point-grid,
.status-grid {
  display: grid;
  gap: 18px;
}

.tool-grid {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

.tool-grid-three,
.point-grid,
.status-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.tool-card,
.point,
.status-card {
  min-height: 100%;
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  box-shadow: var(--shadow);
}

.tool-card {
  display: grid;
  align-content: start;
  gap: 10px;
  text-decoration: none;
}

.tool-card-featured {
  border-color: rgba(15, 118, 110, 0.35);
  background: linear-gradient(180deg, #ffffff, var(--surface-soft));
}

.tool-card-muted {
  box-shadow: none;
}

.tool-card:hover {
  border-color: var(--accent);
}

.tool-kicker {
  color: var(--accent);
  font-size: 0.78rem;
  font-weight: 800;
  text-transform: uppercase;
}

.tool-label {
  color: var(--text);
  font-size: 1.15rem;
  font-weight: 800;
}

.tool-description {
  color: var(--muted);
}

.tool-action {
  margin-top: 8px;
  color: var(--accent);
  font-weight: 800;
}

.tool-action.inactive {
  color: var(--muted);
}

.why-section,
.related-section {
  border-top: 1px solid var(--line);
}

.point {
  display: grid;
  gap: 10px;
}

.point-number {
  color: var(--accent);
  font-size: 0.82rem;
  font-weight: 800;
}

.page-intro {
  padding: 54px 0 34px;
}

.page-intro p {
  margin-top: 16px;
  font-size: 1.06rem;
}

.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 24px;
  color: var(--muted);
  font-size: 0.92rem;
}

.breadcrumb a {
  color: var(--accent);
  font-weight: 800;
  text-decoration: none;
}

.breadcrumb a:hover {
  color: var(--accent-dark);
}

.calculator {
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: 28px;
  padding: 34px;
  border: 1px solid rgba(15, 118, 110, 0.24);
  border-radius: 8px;
  background: var(--surface);
  box-shadow: var(--shadow);
}

.calculator-copy {
  display: grid;
  align-content: start;
  gap: 14px;
}

.battery-form,
.diagnosis-form {
  display: grid;
  gap: 18px;
}

.form-field {
  display: grid;
  gap: 8px;
}

label {
  font-weight: 800;
}

input,
select {
  width: 100%;
  min-height: 50px;
  padding: 10px 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #ffffff;
  color: var(--text);
  font: inherit;
}

select {
  cursor: pointer;
}

input:focus,
select:focus {
  border-color: var(--accent);
  outline: 3px solid rgba(15, 118, 110, 0.18);
}

.result {
  grid-column: 2;
  min-height: 116px;
  padding: 20px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--bg);
}

.result-placeholder,
.result-note {
  color: var(--muted);
}

.result-value {
  font-size: 2rem;
  font-weight: 800;
}

.result-title {
  margin-bottom: 8px;
  font-size: 1.15rem;
  font-weight: 800;
}

.result-list {
  margin: 10px 0 0;
  padding-left: 20px;
  color: var(--muted);
}

.result-list li + li {
  margin-top: 6px;
}

.status {
  margin-top: 4px;
  font-weight: 800;
}

.status-good {
  color: var(--accent-dark);
}

.status-moderate,
.priority-medium {
  color: var(--warning);
}

.status-replace,
.priority-high,
.error {
  color: var(--danger);
}

.priority-low {
  color: var(--accent-dark);
}

.error {
  font-weight: 800;
}

.text-section,
.faq-section {
  display: grid;
  gap: 16px;
}

.text-section a {
  color: var(--accent);
  font-weight: 800;
}

.step-list {
  display: grid;
  gap: 14px;
  max-width: 820px;
  margin: 0;
  padding-left: 22px;
  color: var(--muted);
}

.step-list strong {
  color: var(--text);
}

.status-card {
  box-shadow: none;
}

.status-card h3 {
  margin-bottom: 8px;
}

details {
  padding: 18px 0;
  border-bottom: 1px solid var(--line);
}

summary {
  cursor: pointer;
  font-weight: 800;
}

details p {
  margin-top: 10px;
}

.site-footer {
  border-top: 1px solid var(--line);
  background: #ffffff;
}

.footer-inner {
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto;
  padding: 34px 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  color: var(--muted);
}

@media (max-width: 940px) {
  .tool-grid,
  .tool-grid-three,
  .point-grid,
  .status-grid,
  .calculator {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .result {
    grid-column: 1 / -1;
  }
}

@media (min-width: 941px) {
  .diagnosis-form {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .diagnosis-form .primary-button {
    grid-column: 1 / -1;
    justify-self: start;
  }
}

@media (max-width: 700px) {
  .nav,
  .footer-inner {
    align-items: flex-start;
    flex-direction: column;
  }

  .nav {
    padding: 14px 0;
  }

  .nav-links {
    gap: 14px;
  }

  .hero {
    min-height: 470px;
  }

  .hero-content,
  .section {
    padding: 52px 0;
  }

  .tool-grid,
  .tool-grid-three,
  .point-grid,
  .status-grid,
  .calculator {
    grid-template-columns: 1fr;
  }

  .calculator {
    padding: 24px;
  }

  .result {
    grid-column: auto;
  }
}