/* === SHARED GLOBAL STYLES === */
/* Input Science / Scientific Typing — Visual DNA */
/* Pure Black #000 & Pure White #FFF only. No grays. */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;900&family=JetBrains+Mono:wght@300;400;500;700&display=swap');

:root {
  --black: #000000;
  --white: #FFFFFF;
  --font-sans: 'Inter', 'Helvetica Neue', Arial, sans-serif;
  --font-mono: 'JetBrains Mono', 'Geist Mono', 'SF Mono', monospace;
  --grid-unit: 8px;
  --max-width: 960px;
  --transition: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-sans);
  background: var(--black);
  color: var(--white);
  line-height: 1.6;
  min-height: 100vh;
}

a {
  color: var(--white);
  text-decoration: none;
  border-bottom: 1px solid var(--white);
  transition: opacity var(--transition);
}

a:hover {
  opacity: 0.6;
}

/* Grid Container */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 calc(var(--grid-unit) * 4);
}

/* Sections */
section {
  padding: calc(var(--grid-unit) * 12) 0;
  border-bottom: 1px solid var(--white);
}

section:last-of-type {
  border-bottom: none;
}

/* Typography */
h1 {
  font-family: var(--font-sans);
  font-size: 3.5rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.1;
}

h2 {
  font-family: var(--font-sans);
  font-size: 2rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.2;
  margin-bottom: calc(var(--grid-unit) * 4);
}

h3 {
  font-family: var(--font-sans);
  font-size: 1.25rem;
  font-weight: 500;
  line-height: 1.4;
  margin-bottom: calc(var(--grid-unit) * 2);
}

.mono {
  font-family: var(--font-mono);
}

.label {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 400;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.subtitle {
  font-family: var(--font-mono);
  font-size: 1.125rem;
  font-weight: 300;
  line-height: 1.6;
}

.small {
  font-size: 0.875rem;
  opacity: 0.7;
}

/* Navigation */
nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: var(--black);
  border-bottom: 1px solid var(--white);
}

nav .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: calc(var(--grid-unit) * 7);
}

nav .brand {
  font-family: var(--font-sans);
  font-weight: 700;
  font-size: 0.875rem;
  border-bottom: none;
  letter-spacing: -0.01em;
}

nav .links {
  display: flex;
  gap: calc(var(--grid-unit) * 4);
}

nav .links a {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.05em;
  border-bottom: none;
}

nav .links a:hover {
  opacity: 0.6;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: calc(var(--grid-unit) * 1);
  font-family: var(--font-mono);
  font-size: 0.875rem;
  font-weight: 500;
  padding: calc(var(--grid-unit) * 2) calc(var(--grid-unit) * 4);
  border: 1px solid var(--white);
  background: transparent;
  color: var(--white);
  cursor: pointer;
  transition: all var(--transition);
  text-decoration: none;
  border-bottom: 1px solid var(--white);
}

.btn:hover {
  background: var(--white);
  color: var(--black);
  opacity: 1;
}

.btn-filled {
  background: var(--white);
  color: var(--black);
}

.btn-filled:hover {
  background: transparent;
  color: var(--white);
}

/* Forms */
input[type="email"] {
  font-family: var(--font-mono);
  font-size: 1rem;
  padding: calc(var(--grid-unit) * 2) calc(var(--grid-unit) * 3);
  background: transparent;
  border: 1px solid var(--white);
  color: var(--white);
  outline: none;
  width: 100%;
  max-width: 400px;
  transition: all var(--transition);
}

input[type="email"]::placeholder {
  color: var(--white);
  opacity: 0.4;
}

input[type="email"]:focus {
  background: var(--white);
  color: var(--black);
}

/* Footer */
footer {
  padding: calc(var(--grid-unit) * 6) 0;
  border-top: 1px solid var(--white);
}

footer .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

footer .footer-links {
  display: flex;
  gap: calc(var(--grid-unit) * 4);
}

footer .footer-links a {
  font-family: var(--font-mono);
  font-size: 0.75rem;
}

footer .copyright {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  opacity: 0.5;
}

/* Spacer */
.spacer-nav {
  height: calc(var(--grid-unit) * 7);
}

/* Utility */
.text-center { text-align: center; }
.mt-1 { margin-top: calc(var(--grid-unit) * 1); }
.mt-2 { margin-top: calc(var(--grid-unit) * 2); }
.mt-3 { margin-top: calc(var(--grid-unit) * 3); }
.mt-4 { margin-top: calc(var(--grid-unit) * 4); }
.mt-6 { margin-top: calc(var(--grid-unit) * 6); }
.mt-8 { margin-top: calc(var(--grid-unit) * 8); }
.mb-2 { margin-bottom: calc(var(--grid-unit) * 2); }
.mb-4 { margin-bottom: calc(var(--grid-unit) * 4); }

/* Responsive */
@media (max-width: 640px) {
  h1 { font-size: 2.25rem; }
  h2 { font-size: 1.5rem; }
  .container { padding: 0 calc(var(--grid-unit) * 3); }
  section { padding: calc(var(--grid-unit) * 8) 0; }
  nav .links { gap: calc(var(--grid-unit) * 2); }
  footer .container { flex-direction: column; gap: calc(var(--grid-unit) * 2); }
}