/* ===========================
   AI2HVAC — Stylesheet
   =========================== */

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

:root {
  --blue: #0057FF;
  --blue-dark: #0040CC;
  --blue-light: #E8F0FF;
  --orange: #FF6B2B;
  --dark: #0D0F14;
  --gray-900: #1A1D24;
  --gray-700: #3A3F4B;
  --gray-500: #6B7280;
  --gray-200: #E5E7EB;
  --gray-100: #F3F4F6;
  --white: #FFFFFF;
  --radius: 12px;
  --shadow: 0 4px 24px rgba(0,0,0,0.08);
  --shadow-lg: 0 12px 48px rgba(0,0,0,0.14);
}

html { scroll-behavior: smooth; }
body { font-family: 'Inter', sans-serif; color: var(--gray-900); background: var(--white); line-height: 1.6; }

.container { max-width: 1140px; margin: 0 auto; padding: 0 24px; }

/* BUTTONS */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  padding: 14px 28px; border-radius: 8px; font-weight: 600; font-size: 1rem;
  text-decoration: none; border: 2px solid transparent; cursor: pointer;
  transition: all 0.2s ease;
}
.btn-sm { padding: 10px 20px; font-size: 0.875rem; }
.btn-lg { padding: 16px 36px; font-size: 1.05rem; }
.btn-full { width: 100%; }
.btn-primary { background: var(--blue); color: var(--white); border-color: var(--blue); }
.btn-primary:hover { background: var(--blue-dark); border-color: var(--blue-dark); transform: translateY(-1px); }
.btn-outline { background: transparent; color: var(--blue); border-color: var(--blue); }
.btn-outline:hover { background: var(--blue-light); }
.btn-ghost { background: transparent; color: var(--gray-700); border-color: var(--gray-200); }
.btn-ghost:hover { background: var(--gray-100); }

/* NAV */
.nav {
  position: sticky; top: 0; z-index: 100; background: rgba(255,255,255,0.95);
  backdrop-filter: blur(10px); border-bottom: 1px solid var(--gray-200);
}
.nav-inner { display: flex; align-items: center; justify-content: space-between; padding-top: 16px; padding-bottom: 16px; }
.logo { font-size: 1.5rem; font-weight: 800; color: var(--dark); text-decoration: none; letter-spacing: -0.5px; }
.logo span { color: var(--blue); }
.nav-links { display: flex; align-items: center; gap: 32px; list-style: none; }
.nav-links a { color: var(--gray-700); text-decoration: none; font-weight: 500; font-size: 0.95rem; transition: color 0.2s; }
.nav-links a:hover { color: var(--blue); }
.nav-toggle { display: none; background: none; border: none; font-size: 1.5rem; cursor: pointer; color: var(--dark); }

/* HERO */
.hero { background: linear-gradient(135deg, #0D0F14 0%, #1a2744 100%); color: var(--white); padding: 100px 0 80px; }
.hero-inner { max-width: 780px; }
.hero-badge { display: inline-flex; align-items: center; gap: 8px; background: rgba(255,255,255,0.1); border: 1px solid rgba(255,255,255,0.2); padding: 6px 16px; border-radius: 100px; font-size: 0.875rem; font-weight: 500; margin-bottom: 24px; }
.hero h1 { font-size: clamp(2rem, 5vw, 3.2rem); font-weight: 800; line-height: 1.15; margin-bottom: 20px; letter-spacing: -1px; }
.highlight { color: var(--orange); }
.hero-sub { font-size: 1.15rem; color: rgba(255,255,255,0.75); max-width: 620px; margin-bottom: 36px; }
.hero-cta { display: flex; gap: 16px; flex-wrap: wrap; margin-bottom: 56px; }
.hero-stats { display: flex; gap: 48px; flex-wrap: wrap; }
.stat { display: flex; flex-direction: column; }
.stat strong { font-size: 2rem; font-weight: 800; color: var(--white); line-height: 1; }
.stat span { font-size: 0.85rem; color: rgba(255,255,255,0.6); margin-top: 4px; }

/* SECTION LABELS */
.section-label { font-size: 0.8rem; font-weight: 700; letter-spacing: 2px; text-transform: uppercase; color: var(--blue); margin-bottom: 12px; }

/* PROBLEMS */
.problems { padding: 100px 0; background: var(--gray-100); }
.problems h2 { font-size: clamp(1.6rem, 3vw, 2.4rem); font-weight: 800; margin-bottom: 48px; max-width: 560px; letter-spacing: -0.5px; }
.problems-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 24px; }
.problem-card { background: var(--white); padding: 32px; border-radius: var(--radius); box-shadow: var(--shadow); border: 1px solid var(--gray-200); transition: transform 0.2s; }
.problem-card:hover { transform: translateY(-4px); }
.problem-icon { font-size: 2rem; margin-bottom: 16px; }
.problem-card h3 { font-size: 1.05rem; font-weight: 700; margin-bottom: 8px; }
.problem-card p { color: var(--gray-500); font-size: 0.95rem; }

/* HOW IT WORKS */
.how { padding: 100px 0; }
.how h2 { font-size: clamp(1.6rem, 3vw, 2.4rem); font-weight: 800; margin-bottom: 56px; letter-spacing: -0.5px; }
.steps { display: flex; align-items: flex-start; gap: 12px; flex-wrap: wrap; }
.step { flex: 1; min-width: 200px; }
.step-num { font-size: 2.5rem; font-weight: 800; color: var(--blue-light); line-height: 1; margin-bottom: 12px; }
.step h3 { font-size: 1.05rem; font-weight: 700; margin-bottom: 8px; }
.step p { color: var(--gray-500); font-size: 0.9rem; }
.step-arrow { font-size: 1.5rem; color: var(--gray-200); margin-top: 16px; align-self: flex-start; }

/* SERVICES */
.services { padding: 100px 0; background: var(--gray-100); }
.services h2 { font-size: clamp(1.6rem, 3vw, 2.4rem); font-weight: 800; margin-bottom: 48px; letter-spacing: -0.5px; }
.plans { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 24px; align-items: start; }
.plan { background: var(--white); border: 2px solid var(--gray-200); border-radius: var(--radius); padding: 36px; position: relative; }
.plan-featured { border-color: var(--blue); box-shadow: var(--shadow-lg); }
.plan-badge { position: absolute; top: -14px; left: 50%; transform: translateX(-50%); background: var(--blue); color: white; padding: 4px 16px; border-radius: 100px; font-size: 0.8rem; font-weight: 700; white-space: nowrap; }
.plan-name { font-size: 1.15rem; font-weight: 700; margin-bottom: 8px; }
.plan-price { font-size: 1rem; color: var(--gray-500); margin-bottom: 4px; }
.plan-price strong { font-size: 2rem; color: var(--dark); font-weight: 800; }
.plan-tagline { font-size: 0.9rem; color: var(--gray-500); margin-bottom: 24px; }
.plan-features { list-style: none; margin-bottom: 28px; }
.plan-features li { padding: 8px 0; font-size: 0.9rem; border-bottom: 1px solid var(--gray-100); color: var(--gray-700); }
.plan-features li:last-child { border-bottom: none; }

/* ABOUT */
.about { padding: 100px 0; }
.about-inner { display: grid; grid-template-columns: 1fr 1fr; gap: 64px; align-items: center; }
.about-text h2 { font-size: clamp(1.6rem, 3vw, 2.4rem); font-weight: 800; margin-bottom: 20px; letter-spacing: -0.5px; }
.about-text p { color: var(--gray-500); margin-bottom: 16px; }
.about-text p strong { color: var(--dark); }
.about-text .btn { margin-top: 8px; }
.about-proof { display: flex; flex-direction: column; gap: 20px; }
.proof-card { background: var(--gray-100); border-radius: var(--radius); padding: 28px; border-left: 4px solid var(--blue); }
.proof-quote { font-style: italic; color: var(--gray-700); margin-bottom: 12px; font-size: 0.95rem; line-height: 1.7; }
.proof-author { font-size: 0.85rem; font-weight: 600; color: var(--blue); }

/* CTA BANNER */
.cta-banner { background: linear-gradient(135deg, var(--blue) 0%, #003DBF 100%); color: white; padding: 80px 0; text-align: center; }
.cta-banner h2 { font-size: clamp(1.6rem, 3vw, 2.4rem); font-weight: 800; margin-bottom: 16px; letter-spacing: -0.5px; }
.cta-banner p { font-size: 1.05rem; opacity: 0.85; max-width: 560px; margin: 0 auto 36px; }
.cta-banner .btn-primary { background: white; color: var(--blue); border-color: white; }
.cta-banner .btn-primary:hover { background: var(--blue-light); }

/* CONTACT */
.contact { padding: 100px 0; background: var(--gray-100); }
.contact-inner { display: grid; grid-template-columns: 1fr 1.4fr; gap: 64px; align-items: start; }
.contact-text h2 { font-size: clamp(1.6rem, 3vw, 2.2rem); font-weight: 800; margin-bottom: 16px; letter-spacing: -0.5px; }
.contact-text p { color: var(--gray-500); margin-bottom: 24px; }
.contact-list { list-style: none; display: flex; flex-direction: column; gap: 12px; }
.contact-list li { color: var(--gray-700); font-size: 0.95rem; }
.contact-form { background: var(--white); padding: 36px; border-radius: var(--radius); box-shadow: var(--shadow); }
.contact-form form { display: flex; flex-direction: column; gap: 16px; }
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.contact-form input,
.contact-form select,
.contact-form textarea {
  padding: 14px 16px; border: 2px solid var(--gray-200); border-radius: 8px;
  font-family: inherit; font-size: 0.95rem; color: var(--dark);
  transition: border-color 0.2s; width: 100%; background: var(--white);
}
.contact-form input:focus,
.contact-form select:focus,
.contact-form textarea:focus { outline: none; border-color: var(--blue); }
.contact-form textarea { resize: vertical; }
.form-note { text-align: center; font-size: 0.8rem; color: var(--gray-500); }

/* FOOTER */
.footer { background: var(--dark); color: white; padding: 48px 0; text-align: center; }
.footer-inner { display: flex; flex-direction: column; align-items: center; gap: 12px; }
.footer .logo { color: white; }
.footer p { color: rgba(255,255,255,0.5); font-size: 0.9rem; }
.footer-copy { font-size: 0.8rem; }

/* RESPONSIVE */
@media (max-width: 768px) {
  .nav-links { display: none; flex-direction: column; position: absolute; top: 65px; left: 0; right: 0; background: white; border-bottom: 1px solid var(--gray-200); padding: 16px 24px; gap: 16px; }
  .nav-links.open { display: flex; }
  .nav-toggle { display: block; }
  .hero { padding: 72px 0 56px; }
  .hero-cta { flex-direction: column; }
  .hero-stats { gap: 28px; }
  .about-inner { grid-template-columns: 1fr; gap: 40px; }
  .contact-inner { grid-template-columns: 1fr; gap: 40px; }
  .form-row { grid-template-columns: 1fr; }
  .steps { flex-direction: column; }
  .step-arrow { display: none; }
}