:root {
  --color-bg: #ffffff;
  --color-text: #1f2933;
  --color-muted: #6b7280;
  --color-primary: #2563eb;
  --color-primary-dark: #1d4ed8;
  --color-border: #e5e7eb;
  --color-surface: #f9fafb;
  --color-error: #dc2626;
  --color-success: #16a34a;
  --radius: 10px;
  --max-width: 1040px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.6;
}

.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.25rem;
}

a { color: var(--color-primary); }

/* Header */
.site-header {
  border-bottom: 1px solid var(--color-border);
  background: var(--color-bg);
  position: sticky;
  top: 0;
  z-index: 10;
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}
.logo {
  font-weight: 700;
  font-size: 1.15rem;
  text-decoration: none;
  color: var(--color-text);
}
.nav a {
  margin-left: 1.5rem;
  text-decoration: none;
  color: var(--color-muted);
  font-weight: 500;
}
.nav a:hover,
.nav a.active { color: var(--color-text); }

/* Hero */
.hero {
  background: var(--color-surface);
  padding: 5rem 0;
  text-align: center;
}
.hero h1 { font-size: 2.6rem; margin: 0 0 1rem; }
.lead { font-size: 1.2rem; color: var(--color-muted); max-width: 620px; margin: 0 auto 1.75rem; }

/* Buttons */
.btn {
  display: inline-block;
  background: var(--color-primary);
  color: #fff;
  padding: 0.75rem 1.5rem;
  border: none;
  border-radius: var(--radius);
  font-size: 1rem;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  transition: background 0.15s ease;
}
.btn:hover { background: var(--color-primary-dark); }

/* Features */
.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.5rem;
  padding-top: 3.5rem;
  padding-bottom: 3.5rem;
}
.card {
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.5rem;
  background: var(--color-bg);
}
.card h2 { margin-top: 0; font-size: 1.25rem; }

/* Form */
.form-section { padding: 3rem 0 4rem; max-width: 640px; }
.form-section h1 { font-size: 2rem; margin-bottom: 0.5rem; }
.contact-form { margin-top: 2rem; }
.field { margin-bottom: 1.25rem; }
.field label { display: block; font-weight: 600; margin-bottom: 0.4rem; }
.field input,
.field textarea {
  width: 100%;
  padding: 0.7rem 0.85rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  font-size: 1rem;
  font-family: inherit;
  background: var(--color-bg);
  color: var(--color-text);
}
.field input:focus,
.field textarea:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}
.field input.invalid,
.field textarea.invalid { border-color: var(--color-error); }
.error {
  display: block;
  color: var(--color-error);
  font-size: 0.875rem;
  margin-top: 0.35rem;
  min-height: 1rem;
}
.form-status {
  margin-top: 1rem;
  font-weight: 600;
}
.form-status.success { color: var(--color-success); }
.form-status.error { color: var(--color-error); }

/* Footer */
.site-footer {
  border-top: 1px solid var(--color-border);
  padding: 1.5rem 0;
  color: var(--color-muted);
  font-size: 0.9rem;
  text-align: center;
}

@media (max-width: 600px) {
  .hero { padding: 3.5rem 0; }
  .hero h1 { font-size: 2rem; }
}