:root {
  --primary: #0b5ed7;
  --primary-dark: #084298;
  --accent: #ff6b35;
  --accent-dark: #e55a2b;
  --bg: #f8fafc;
  --surface: #ffffff;
  --text: #0f172a;
  --muted: #64748b;
  --border: #e2e8f0;
  --success: #16a34a;
  --warning: #d97706;
  --danger: #dc2626;
  --radius: 12px;
  --shadow: 0 4px 12px rgba(15, 23, 42, 0.06);
  --shadow-lg: 0 12px 32px rgba(15, 23, 42, 0.12);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

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

.container {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 24px;
}

/* Header */
.site-header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 0;
}
.logo {
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--text);
  display: flex;
  align-items: center;
  gap: 8px;
}
.logo-mark {
  width: 32px;
  height: 32px;
  display: block;
}
.nav-links {
  display: flex;
  gap: 28px;
  list-style: none;
}
.nav-links a {
  color: var(--text);
  font-weight: 500;
  font-size: 0.95rem;
}
.nav-cta {
  background: var(--accent);
  color: white !important;
  padding: 10px 20px;
  border-radius: 8px;
  font-weight: 600;
  transition: background 0.2s;
}
.nav-cta:hover { background: var(--accent-dark); text-decoration: none; }

/* Hero */
.hero {
  padding: 80px 0 60px;
  text-align: center;
  background: linear-gradient(180deg, #ffffff 0%, var(--bg) 100%);
}
.hero h1 {
  font-size: clamp(2rem, 5vw, 3.25rem);
  font-weight: 800;
  line-height: 1.15;
  margin-bottom: 20px;
  letter-spacing: -0.02em;
}
.hero h1 span {
  background: linear-gradient(135deg, var(--primary), var(--accent));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.hero p {
  font-size: 1.2rem;
  color: var(--muted);
  max-width: 640px;
  margin: 0 auto 32px;
}
.btn {
  display: inline-block;
  padding: 14px 28px;
  border-radius: 10px;
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  border: none;
  transition: all 0.2s;
  text-decoration: none;
}
.btn-primary {
  background: var(--accent);
  color: white;
  box-shadow: 0 4px 12px rgba(255, 107, 53, 0.3);
}
.btn-primary:hover {
  background: var(--accent-dark);
  transform: translateY(-1px);
  text-decoration: none;
}
.btn-secondary {
  background: var(--surface);
  color: var(--text);
  border: 1px solid var(--border);
}
.btn-secondary:hover { background: #f1f5f9; text-decoration: none; }

/* Sections */
section { padding: 64px 0; }
.section-title {
  text-align: center;
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 12px;
  letter-spacing: -0.01em;
}
.section-subtitle {
  text-align: center;
  color: var(--muted);
  font-size: 1.1rem;
  margin-bottom: 48px;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

/* Features grid */
.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px;
}
.feature-card {
  background: var(--surface);
  padding: 28px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  transition: transform 0.2s, box-shadow 0.2s;
}
.feature-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}
.feature-icon {
  width: 48px;
  height: 48px;
  background: #eff6ff;
  color: var(--primary);
  border-radius: 10px;
  display: grid;
  place-items: center;
  font-size: 1.5rem;
  margin-bottom: 16px;
}
.feature-card h3 {
  font-size: 1.15rem;
  margin-bottom: 8px;
}
.feature-card p {
  color: var(--muted);
  font-size: 0.95rem;
}

/* Appliances */
.appliances {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 16px;
  max-width: 900px;
  margin: 0 auto;
}
.appliance {
  background: var(--surface);
  padding: 24px;
  border-radius: var(--radius);
  text-align: center;
  border: 1px solid var(--border);
  transition: all 0.2s;
  cursor: pointer;
}
.appliance:hover {
  border-color: var(--primary);
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}
.appliance-emoji { font-size: 2.5rem; margin-bottom: 8px; }
.appliance-name { font-weight: 600; }

/* Diagnosis form */
.diagnose-wrap {
  max-width: 720px;
  margin: 40px auto;
  background: var(--surface);
  border-radius: var(--radius);
  padding: 40px;
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--border);
}
.step { display: none; }
.step.active { display: block; }
.step-indicator {
  display: flex;
  justify-content: space-between;
  margin-bottom: 32px;
  position: relative;
}
.step-indicator::before {
  content: "";
  position: absolute;
  top: 16px;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--border);
  z-index: 0;
}
.step-dot {
  width: 34px;
  height: 34px;
  border-radius: 50%;
  background: var(--surface);
  border: 2px solid var(--border);
  display: grid;
  place-items: center;
  font-weight: 600;
  font-size: 0.9rem;
  z-index: 1;
  color: var(--muted);
}
.step-dot.active {
  background: var(--primary);
  border-color: var(--primary);
  color: white;
}
.step-dot.done {
  background: var(--success);
  border-color: var(--success);
  color: white;
}

h2.step-title {
  font-size: 1.5rem;
  margin-bottom: 8px;
}
.step-desc {
  color: var(--muted);
  margin-bottom: 24px;
}

.field-group { margin-bottom: 20px; }
label {
  display: block;
  font-weight: 600;
  margin-bottom: 8px;
  font-size: 0.95rem;
}
input[type="text"], input[type="number"], input[type="email"], select, textarea {
  width: 100%;
  padding: 12px 14px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 1rem;
  font-family: inherit;
  background: var(--surface);
  transition: border-color 0.2s, box-shadow 0.2s;
}
input:focus, select:focus, textarea:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(11, 94, 215, 0.1);
}

.option-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 12px;
  margin-bottom: 20px;
}
.option {
  padding: 16px;
  border: 2px solid var(--border);
  border-radius: 10px;
  text-align: center;
  cursor: pointer;
  font-weight: 500;
  transition: all 0.15s;
  background: var(--surface);
}
.option:hover { border-color: var(--primary); }
.option.selected {
  border-color: var(--primary);
  background: #eff6ff;
  color: var(--primary-dark);
}
.option-emoji { font-size: 1.75rem; display: block; margin-bottom: 4px; }

.checkbox-group {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 10px;
}
.checkbox-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.15s;
}
.checkbox-item:hover { border-color: var(--primary); }
.checkbox-item input { width: auto; margin: 0; }
.checkbox-item.checked {
  border-color: var(--primary);
  background: #eff6ff;
}

.step-actions {
  display: flex;
  justify-content: space-between;
  margin-top: 32px;
  gap: 12px;
}

/* Results */
.result-hero {
  text-align: center;
  padding: 60px 0 40px;
}
.score-circle {
  width: 180px;
  height: 180px;
  border-radius: 50%;
  margin: 0 auto 24px;
  display: grid;
  place-items: center;
  color: white;
  font-weight: 800;
  font-size: 3rem;
  box-shadow: var(--shadow-lg);
  position: relative;
}
.score-circle.fix { background: linear-gradient(135deg, #16a34a, #22c55e); }
.score-circle.replace { background: linear-gradient(135deg, #dc2626, #f97316); }
.score-circle.maybe { background: linear-gradient(135deg, #d97706, #f59e0b); }
.score-label {
  font-size: 0.9rem;
  font-weight: 500;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  opacity: 0.9;
}
.verdict {
  font-size: 2.25rem;
  font-weight: 800;
  margin-bottom: 12px;
}
.verdict-sub {
  color: var(--muted);
  font-size: 1.1rem;
  max-width: 560px;
  margin: 0 auto;
}

.result-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
  margin: 40px 0;
}
.result-card {
  background: var(--surface);
  padding: 24px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
}
.result-card h3 {
  font-size: 1.05rem;
  margin-bottom: 12px;
  color: var(--muted);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  font-size: 0.8rem;
}
.result-card .big {
  font-size: 2rem;
  font-weight: 800;
  color: var(--text);
}
.result-card .sub { color: var(--muted); font-size: 0.9rem; margin-top: 4px; }

.breakdown {
  background: var(--surface);
  padding: 32px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  margin: 32px 0;
}
.breakdown h3 {
  font-size: 1.3rem;
  margin-bottom: 20px;
}
.factor {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 0;
  border-bottom: 1px solid var(--border);
}
.factor:last-child { border-bottom: none; }
.factor-name { font-weight: 500; }
.factor-bar {
  flex: 1;
  margin: 0 20px;
  height: 8px;
  background: var(--border);
  border-radius: 4px;
  overflow: hidden;
}
.factor-fill {
  height: 100%;
  border-radius: 4px;
  transition: width 0.6s ease;
}
.factor-value { font-weight: 700; min-width: 60px; text-align: right; }

.next-steps {
  background: linear-gradient(135deg, #eff6ff, #fef3c7);
  padding: 32px;
  border-radius: var(--radius);
  margin: 32px 0;
}
.next-steps h3 { font-size: 1.3rem; margin-bottom: 16px; }
.next-steps ul { list-style: none; }
.next-steps li {
  padding: 8px 0;
  padding-left: 28px;
  position: relative;
}
.next-steps li::before {
  content: "✓";
  position: absolute;
  left: 0;
  color: var(--success);
  font-weight: 700;
}

/* About / How / Contact */
.page-hero {
  padding: 60px 0 40px;
  text-align: center;
}
.page-hero h1 {
  font-size: clamp(2rem, 4vw, 2.75rem);
  font-weight: 800;
  margin-bottom: 16px;
}
.page-hero p {
  color: var(--muted);
  font-size: 1.15rem;
  max-width: 640px;
  margin: 0 auto;
}

.content-section {
  max-width: 760px;
  margin: 0 auto;
  padding: 40px 0;
}
.content-section h2 {
  font-size: 1.5rem;
  margin: 32px 0 12px;
}
.content-section p { margin-bottom: 16px; color: #334155; }

.steps-list {
  counter-reset: step;
  list-style: none;
}
.steps-list li {
  counter-increment: step;
  padding: 24px;
  padding-left: 72px;
  background: var(--surface);
  border-radius: var(--radius);
  border: 1px solid var(--border);
  margin-bottom: 16px;
  position: relative;
  box-shadow: var(--shadow);
}
.steps-list li::before {
  content: counter(step);
  position: absolute;
  left: 20px;
  top: 50%;
  transform: translateY(-50%);
  width: 40px;
  height: 40px;
  background: var(--primary);
  color: white;
  border-radius: 50%;
  display: grid;
  place-items: center;
  font-weight: 700;
}
.steps-list h3 { margin-bottom: 6px; }
.steps-list p { color: var(--muted); margin: 0; }

/* Contact form */
.contact-form {
  max-width: 560px;
  margin: 40px auto;
  background: var(--surface);
  padding: 32px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
}

/* Footer */
.site-footer {
  background: #0f172a;
  color: #cbd5e1;
  padding: 48px 0 24px;
  margin-top: 64px;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 32px;
}
.footer-brand p {
  font-size: 0.95rem;
  margin-top: 12px;
  color: #94a3b8;
}
.footer-col h4 {
  color: white;
  font-size: 0.95rem;
  margin-bottom: 14px;
}
.footer-col ul { list-style: none; }
.footer-col li { margin-bottom: 8px; }
.footer-col a { color: #94a3b8; font-size: 0.9rem; }
.footer-col a:hover { color: white; }
.footer-bottom {
  border-top: 1px solid #1e293b;
  padding-top: 20px;
  display: flex;
  justify-content: space-between;
  font-size: 0.85rem;
  color: #64748b;
  flex-wrap: wrap;
  gap: 12px;
}

/* Brands by Category Section */
.brands-by-category {
  margin-top: 48px;
}
.category-block {
  margin-bottom: 48px;
}
.category-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 20px;
  padding-bottom: 12px;
  border-bottom: 2px solid var(--border);
}
.category-emoji {
  font-size: 2rem;
}
.category-name {
  font-size: 1.5rem;
  font-weight: 700;
}
.brands-list {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}
.brand-chip {
  padding: 10px 18px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  font-weight: 500;
  font-size: 0.95rem;
  transition: all 0.2s;
  cursor: default;
}
.brand-chip:hover {
  border-color: var(--primary);
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}

/* Responsive */
@media (max-width: 768px) {
  .nav-links { display: none; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .diagnose-wrap { padding: 24px; }
  .hero { padding: 48px 0 32px; }
  section { padding: 48px 0; }
}