/* ===== Custom Properties ===== */
:root {
  --color-bg: #fafafa;
  --color-surface: #ffffff;
  --color-text: #1a1a2e;
  --color-text-muted: #555770;
  --color-accent: #4f46e5;
  --color-accent-hover: #4338ca;
  --color-border: #e5e5ea;
  --font-stack: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --max-width: 1120px;
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 2rem;
  --spacing-lg: 4rem;
  --spacing-xl: 6rem;
  --radius: 8px;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-stack);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

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

/* ===== Utility ===== */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

.section {
  padding: var(--spacing-xl) 0;
}

.btn {
  display: inline-block;
  padding: 0.75rem 1.75rem;
  background: var(--color-accent);
  color: #fff;
  border: none;
  border-radius: var(--radius);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.2s ease;
}

.btn:hover { background: var(--color-accent-hover); color: #fff; }

.btn--outline {
  background: transparent;
  color: var(--color-accent);
  border: 2px solid var(--color-accent);
}

.btn--outline:hover {
  background: var(--color-accent);
  color: #fff;
}

/* ===== Nav ===== */
.nav {
  position: sticky;
  top: 0;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  z-index: 100;
}

.nav .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.nav__logo {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text);
}

.nav__links {
  display: flex;
  gap: var(--spacing-md);
  list-style: none;
}

.nav__links a {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  font-weight: 500;
  transition: color 0.2s;
}

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

/* ===== Hero ===== */
.hero {
  padding: var(--spacing-xl) 0;
  text-align: center;
}

.hero__headline {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin-bottom: var(--spacing-sm);
}

.hero__sub {
  font-size: clamp(1rem, 2vw, 1.25rem);
  color: var(--color-text-muted);
  max-width: 600px;
  margin: 0 auto var(--spacing-md);
}

/* ===== Features ===== */
.features {
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.features__grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--spacing-md);
}

.feature-card {
  padding: var(--spacing-md);
  border-radius: var(--radius);
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  transition: box-shadow 0.2s ease;
}

.feature-card:hover {
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.06);
}

.feature-card__icon {
  font-size: 2rem;
  margin-bottom: var(--spacing-sm);
}

.feature-card__title {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: var(--spacing-xs);
}

.feature-card__desc {
  color: var(--color-text-muted);
  font-size: 0.95rem;
}

/* ===== About ===== */
.about__inner {
  max-width: 720px;
  margin: 0 auto;
  text-align: center;
}

.about__title {
  font-size: 2rem;
  font-weight: 800;
  margin-bottom: var(--spacing-sm);
}

.about__text {
  color: var(--color-text-muted);
  font-size: 1.05rem;
}

/* ===== CTA ===== */
.cta {
  background: var(--color-text);
  color: #fff;
}

.cta__inner {
  text-align: center;
  max-width: 600px;
  margin: 0 auto;
}

.cta__title {
  font-size: 1.75rem;
  font-weight: 800;
  margin-bottom: var(--spacing-xs);
}

.cta__sub {
  color: rgba(255, 255, 255, 0.7);
  margin-bottom: var(--spacing-md);
}

.cta__form {
  display: flex;
  gap: var(--spacing-xs);
  justify-content: center;
  flex-wrap: wrap;
}

.cta__input {
  padding: 0.75rem 1rem;
  border: 2px solid rgba(255, 255, 255, 0.2);
  border-radius: var(--radius);
  background: rgba(255, 255, 255, 0.1);
  color: #fff;
  font-size: 1rem;
  flex: 1;
  min-width: 220px;
  max-width: 320px;
}

.cta__input::placeholder { color: rgba(255, 255, 255, 0.5); }

.cta__input:focus {
  outline: none;
  border-color: var(--color-accent);
}

.cta .btn {
  background: #fff;
  color: var(--color-text);
}

.cta .btn:hover { background: var(--color-border); }

/* ===== Footer ===== */
.footer {
  padding: var(--spacing-md) 0;
  border-top: 1px solid var(--color-border);
}

.footer .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
}

.footer__copy {
  color: var(--color-text-muted);
  font-size: 0.85rem;
}

.footer__socials {
  display: flex;
  gap: var(--spacing-sm);
  list-style: none;
}

.footer__socials a {
  color: var(--color-text-muted);
  font-size: 0.85rem;
  transition: color 0.2s;
}

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

/* ===== Responsive ===== */
@media (max-width: 640px) {
  .nav__links { display: none; }
  .hero { padding: var(--spacing-lg) 0; }
  .section { padding: var(--spacing-lg) 0; }
}