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

/* BASE */
html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  scroll-behavior: smooth;
}

body {
  background: #E0E0E0;
  color: #000000;
  font-family: 'Courier New', Courier, monospace;
  line-height: 1.6;
}

/* GLOBAL NAV — PATCH 1A */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  padding: 24px 32px;
  z-index: 100;
}

.nav-logo {
  display: inline-block;
  line-height: 0;
}

.nav-logo img {
  width: 56px;
  height: 56px;
  display: block;
}

/* SECTION RHYTHM */
.section {
  max-width: 720px;
  margin: 0 auto;
  padding: 64px 24px;
  border-bottom: 2px solid #000000;
}

.section:last-child {
  border-bottom: none;
}

/* SYSTEM HEADER */
.section--header {
  padding-top: 96px;
  padding-bottom: 64px;
  text-align: center;
}

.section--header h1 {
  font-size: 2.4rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  line-height: 1.2;
}

.section--header .subtitle {
  font-size: 1rem;
  font-weight: 400;
  letter-spacing: 0.3em;
  margin-top: 16px;
}

/* SYSTEM DEFINITION */
.section--definition p {
  font-size: 0.95rem;
  margin-bottom: 24px;
  line-height: 1.8;
}

.section--definition p:last-child {
  margin-bottom: 0;
}

/* MODULE OVERVIEW */
.section--modules {
  padding-top: 48px;
  padding-bottom: 48px;
}

.module {
  border: 2px solid #000000;
  padding: 32px 24px;
  margin-bottom: 24px;
}

.module:last-child {
  margin-bottom: 0;
}

.module h2 {
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  margin-bottom: 16px;
  border-bottom: 1px solid #000000;
  padding-bottom: 12px;
}

.module p {
  font-size: 0.85rem;
  line-height: 1.7;
  margin-bottom: 8px;
}

.module p:last-child {
  margin-bottom: 0;
}

/* TERMINAL BLOCK — PATCH 4 */
.terminal-block {
  font-family: 'Courier New', Courier, monospace;
  background: #000000;
  color: #FFFFFF;
  padding: 12px;
  border: 2px solid #000000;
  margin-top: 16px;
}

.terminal-block p {
  color: #FFFFFF;
  margin-bottom: 4px;
  font-size: 0.8rem;
  line-height: 1.6;
}

.terminal-block p:last-child {
  margin-bottom: 0;
}

/* FORENSIC CHAIN — PATCH 2 */
.section--chain {
  padding-top: 48px;
  padding-bottom: 48px;
}

.chain {
  display: flex;
  gap: 12px;
  font-family: 'Courier New', Courier, monospace;
  flex-wrap: wrap;
  justify-content: center;
}

.chain-node {
  border: 2px solid #000000;
  padding: 8px 12px;
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.08em;
}

.chain-arrow {
  align-self: center;
  font-size: 1rem;
  font-weight: 700;
}

/* INACTION VISIBILITY */
.section--inaction {
  text-align: center;
}

.section--inaction h2 {
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  margin-bottom: 32px;
  color: #FF3B30;
}

.section--inaction p {
  font-size: 0.9rem;
  margin-bottom: 20px;
  line-height: 1.8;
}

.section--inaction p:last-child {
  margin-bottom: 0;
}

/* SIGNAL TEXT — PATCH 3B */
.signal-text {
  color: #FF3B30;
}

/* TERMINAL ACTION */
.section--terminal {
  text-align: center;
  padding: 80px 24px;
}

/* CTA — PATCH 3A */
.cta {
  display: inline-block;
  font-family: 'Courier New', Courier, monospace;
  font-size: 0.9rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: #FFFFFF;
  background: #FF3B30;
  border: 2px solid #FF3B30;
  padding: 18px 48px;
  text-decoration: none;
  cursor: pointer;
}

.cta:hover {
  opacity: 0.85;
}

/* RESPONSIVE */
@media (max-width: 480px) {
  .section--header h1 {
    font-size: 1.6rem;
  }

  .section {
    padding: 48px 16px;
  }

  .cta {
    padding: 16px 32px;
    font-size: 0.8rem;
  }

  .chain {
    flex-direction: column;
    align-items: center;
  }

  .chain-arrow {
    transform: rotate(90deg);
  }
}