/* ============================================
   NexaVision.tech 2.0 — Design System
   "Let the Truth Be a Lion"
   ============================================ */

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

/* --- Custom Properties --- */
:root {
  /* Colors */
  --color-bg-primary: #1a1a2e;
  --color-bg-secondary: rgba(42, 42, 58, 0.6);
  --color-bg-card: rgba(42, 42, 58, 0.4);
  --color-bg-card-hover: rgba(42, 42, 58, 0.8);
  --color-bg-input: rgba(26, 26, 46, 0.6);
  --color-border: #c9c9c9;
  --color-border-accent: rgba(83, 218, 255, 0.3);

  --color-text-primary: #e8e8e8;
  --color-text-secondary: #aaa;
  --color-text-muted: #888;

  --color-accent: #53daff;
  --color-accent-hover: #ffffff;
  --color-cyan: #64e3c2;
  --color-cyan-hover: #53daff;
  --color-success: #64e3c2;
  --color-warning: #f7a04a;
  --color-rose: #f2849e;
  --color-purple: #ae85ca;

  /* Typography */
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 2rem;
  --text-4xl: 2.5rem;
  --text-5xl: 3.25rem;

  /* Spacing */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;

  /* Layout */
  --max-width: 1200px;
  --nav-height: 64px;
  --border-radius: 8px;
  --border-radius-lg: 12px;

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 400ms ease;

  /* Shadows */
  --shadow-sm: 0 4px 15px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 15px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 6px 20px rgba(83, 218, 255, 0.08), 0 4px 15px rgba(0, 0, 0, 0.4);
  --shadow-glow: 0 0 8px rgba(83, 218, 255, 0.25), 0 0 25px rgba(83, 218, 255, 0.1);
  
  /* Glassmorphism */
  --glass-blur: blur(12px);
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-body);
  font-size: var(--text-base);
  line-height: 1.7;
  color: var(--color-text-primary);
  background-color: var(--color-bg-primary);
  background-image: linear-gradient(rgba(13, 17, 23, 0.75), rgba(13, 17, 23, 0.75)), url('../images/background.webp');
  background-size: cover;
  background-position: center;
  background-attachment: fixed;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

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

a {
  color: var(--color-cyan);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--color-cyan-hover);
}

ul, ol {
  list-style: none;
}

/* --- Typography --- */
h1, h2, h3, h4 {
  font-weight: 600;
  line-height: 1.3;
  color: var(--color-text-primary);
}

h1 {
  font-size: var(--text-4xl);
  letter-spacing: -0.02em;
}

h2 {
  font-size: var(--text-2xl);
  letter-spacing: -0.01em;
}

h3 {
  font-size: var(--text-xl);
}

h4 {
  font-size: var(--text-lg);
  color: var(--color-text-secondary);
}

p {
  margin-bottom: var(--space-4);
  color: var(--color-text-secondary);
}

code {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  background: var(--color-bg-secondary);
  padding: 0.15em 0.4em;
  border-radius: 4px;
  color: var(--color-accent);
}

.text-accent { color: var(--color-accent); }
.text-cyan { color: var(--color-cyan); }
.text-muted { color: var(--color-text-muted); }

/* --- Layout --- */
.site-container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-6);
}

.section {
  padding: var(--space-16) 0;
}

.section + .section {
  border-top: 1px solid var(--color-border);
}

/* --- Navigation --- */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background: rgba(26, 26, 46, 0.7);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border-bottom: 1px solid rgba(255,255,255,0.05);
  z-index: 1000;
  transition: background var(--transition-base);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-6);
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-weight: 600;
  font-size: var(--text-lg);
  color: var(--color-text-primary);
  text-decoration: none;
}

.nav-logo:hover {
  color: var(--color-text-primary);
}

.nav-logo img {
  width: 32px;
  height: 32px;
  border-radius: 6px;
}

.nav-links {
  display: flex;
  gap: var(--space-8);
  align-items: center;
}

.nav-links a {
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
  text-decoration: none;
  padding: var(--space-2) 0;
  position: relative;
  transition: color var(--transition-fast);
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-accent);
  transition: width var(--transition-base);
}

.nav-links a:hover {
  color: var(--color-text-primary);
}

.nav-links a:hover::after {
  width: 100%;
}

.nav-links a.active {
  color: var(--color-accent);
}

.nav-links a.active::after {
  width: 100%;
}

/* Mobile hamburger */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-2);
  color: var(--color-text-primary);
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: currentColor;
  margin: 5px 0;
  transition: transform var(--transition-base), opacity var(--transition-fast);
}

.nav-toggle.open span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}
.nav-toggle.open span:nth-child(2) {
  opacity: 0;
}
.nav-toggle.open span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

/* --- Hero --- */
.hero {
  min-height: 70vh;
  display: flex;
  align-items: center;
  padding-top: calc(var(--nav-height) + var(--space-16));
  padding-bottom: var(--space-16);
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background:
    radial-gradient(ellipse at 20% 50%, rgba(242, 132, 158, 0.06) 0%, transparent 50%),
    radial-gradient(ellipse at 80% 20%, rgba(0, 204, 255, 0.05) 0%, transparent 50%);
  pointer-events: none;
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 720px;
}

.hero-label {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 500;
  color: var(--color-accent);
  text-transform: uppercase;
  letter-spacing: 0.15em;
  margin-bottom: var(--space-4);
  padding: var(--space-1) var(--space-3);
  border: 1px solid rgba(242, 132, 158, 0.3);
  border-radius: 4px;
  background: rgba(242, 132, 158, 0.06);
}

.hero h1 {
  font-size: var(--text-5xl);
  margin-bottom: var(--space-6);
  background: linear-gradient(135deg, var(--color-text-primary) 0%, var(--color-text-secondary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero p {
  font-size: var(--text-lg);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-8);
  max-width: 580px;
}

/* --- Buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-6);
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: 500;
  border-radius: var(--border-radius);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all var(--transition-base);
  text-decoration: none;
}

.btn-primary {
  background: var(--color-accent);
  color: #0d1117;
  border-color: var(--color-accent);
}

.btn-primary:hover {
  background: var(--color-accent-hover);
  border-color: var(--color-accent-hover);
  color: #0d1117;
  box-shadow: var(--shadow-glow);
  transform: translateY(-1px);
}

.btn-secondary {
  background: transparent;
  color: var(--color-text-primary);
  border-color: var(--color-border);
}

.btn-secondary:hover {
  border-color: var(--color-text-secondary);
  background: var(--color-bg-secondary);
  transform: translateY(-1px);
}

/* --- Cards Grid --- */
.grid {
  display: grid;
  gap: var(--space-6);
  grid-template-columns: 1fr;
}

.card {
  background: var(--color-bg-card);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border: 1px solid rgba(83, 218, 255, 0.15);
  border-radius: var(--border-radius-lg);
  padding: var(--space-8);
  transition: all var(--transition-base);
  text-decoration: none;
  display: block;
  position: relative;
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--color-accent), var(--color-cyan));
  opacity: 0;
  transition: opacity var(--transition-base);
}

.card:hover {
  background: var(--color-bg-card-hover);
  border-color: var(--color-accent);
  box-shadow: var(--shadow-lg), var(--shadow-glow);
  transform: translateY(-4px);
}

.card:hover::before {
  opacity: 1;
}

.card-icon {
  font-size: var(--text-3xl);
  margin-bottom: var(--space-4);
  display: block;
}

.card h3 {
  margin-bottom: var(--space-2);
  color: var(--color-text-primary);
}

.card p {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  margin-bottom: 0;
}

.card .card-tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  margin-top: var(--space-4);
}

/* --- Section Header --- */
.section-header {
  margin-bottom: var(--space-12);
}

.section-header h2 {
  margin-bottom: var(--space-3);
}

.section-header p {
  max-width: 600px;
  color: var(--color-text-muted);
}

/* --- Signal Log Entries --- */
.signal-entry {
  border-left: 3px solid var(--color-rose);
  padding: var(--space-6) var(--space-8);
  margin-bottom: var(--space-6);
  background: rgba(242, 132, 158, 0.08);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border-radius: 0 var(--border-radius) var(--border-radius) 0;
  transition: border-color var(--transition-base);
}

.signal-entry:hover {
  border-left-color: var(--color-accent);
}

.signal-timestamp {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-accent);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-bottom: var(--space-3);
  display: block;
}

.signal-entry h3 {
  margin-bottom: var(--space-3);
  font-size: var(--text-lg);
}

.signal-entry p {
  font-size: var(--text-sm);
}

/* --- About / Bio --- */
.bio {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-8);
  align-items: start;
}

.bio-text h3 {
  margin-bottom: var(--space-4);
}

.credential {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) 0;
  border-bottom: 1px solid var(--color-border);
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
}

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

.credential-icon {
  font-size: var(--text-lg);
  width: 32px;
  text-align: center;
  flex-shrink: 0;
}

/* --- Contact Form --- */
.form-group {
  margin-bottom: var(--space-5);
}

.form-group label {
  display: block;
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-2);
}

.form-input,
.form-textarea {
  width: 100%;
  padding: var(--space-3) var(--space-4);
  font-family: var(--font-body);
  font-size: var(--text-base);
  color: var(--color-text-primary);
  background: var(--color-bg-input);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
  outline: none;
}

.form-input:focus,
.form-textarea:focus {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(242, 132, 158, 0.15);
}

.form-textarea {
  min-height: 140px;
  resize: vertical;
}

/* --- Footer --- */
.footer {
  padding: var(--space-10) 0;
  border-top: 1px solid rgba(255,255,255,0.05);
  background: rgba(26, 26, 46, 0.7);
  backdrop-filter: var(--glass-blur);
  text-align: center;
  position: relative;
}

.footer .heart-icon {
  color: var(--color-rose);
  font-size: 1.2em;
  transition: transform var(--transition-base), text-shadow var(--transition-base);
  display: inline-block;
}

.footer a:hover .heart-icon {
  transform: scale(1.2);
  text-shadow: 0 0 10px var(--color-rose);
}

.footer ul.copyright {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  color: var(--color-text-muted);
  font-size: var(--text-sm);
}

@media (min-width: 768px) {
  .footer ul.copyright {
    flex-direction: row;
    justify-content: center;
    gap: var(--space-4);
  }
  .footer ul.copyright li:not(:last-child)::after {
    content: '|';
    margin-left: var(--space-4);
    color: var(--color-border);
  }
}

.footer ul.copyright a {
  color: var(--color-text-secondary);
}

.footer ul.copyright a:hover {
  color: var(--color-accent);
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: var(--space-6);
  margin-top: var(--space-4);
}

.footer-links a {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

.footer-links a:hover {
  color: var(--color-accent);
  text-shadow: var(--shadow-glow);
}

/* --- Utilities --- */
.text-center { text-align: center; }
.mt-1 { margin-top: var(--space-4); }
.mt-2 { margin-top: var(--space-8); }
.mt-3 { margin-top: var(--space-12); }
.mt-4 { margin-top: var(--space-16); }
.mb-1 { margin-bottom: var(--space-4); }
.mb-2 { margin-bottom: var(--space-8); }

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* --- Responsive --- */
@media (min-width: 640px) {
  .grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .bio {
    grid-template-columns: 1fr 1fr;
  }
}

@media (min-width: 960px) {
  .grid {
    grid-template-columns: repeat(3, 1fr);
  }

  h1 {
    font-size: var(--text-5xl);
  }
}

@media (max-width: 768px) {
  :root {
    --text-5xl: 2.25rem;
    --text-4xl: 1.875rem;
    --text-3xl: 1.5rem;
  }

  .nav-links {
    display: none;
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    bottom: 0;
    flex-direction: column;
    background: rgba(13, 17, 23, 0.98);
    backdrop-filter: blur(16px);
    padding: var(--space-8);
    gap: var(--space-6);
  }

  .nav-links.open {
    display: flex;
  }

  .nav-links a {
    font-size: var(--text-lg);
  }

  .nav-toggle {
    display: block;
  }

  .hero {
    min-height: 50vh;
    padding-top: calc(var(--nav-height) + var(--space-8));
  }

  .card {
    padding: var(--space-6);
  }

  .signal-entry {
    padding: var(--space-4) var(--space-5);
  }
}

/* --- Page header for sub-pages --- */
.page-header {
  padding-top: calc(var(--nav-height) + var(--space-12));
  padding-bottom: var(--space-10);
  border-bottom: 1px solid var(--color-border);
}

.page-header h1 {
  margin-bottom: var(--space-3);
}

.page-header p {
  max-width: 600px;
  color: var(--color-text-muted);
}

/* --- Content prose (for research pages) --- */
.prose {
  max-width: 720px;
}

.prose h2 {
  margin-top: var(--space-10);
  margin-bottom: var(--space-4);
}

.prose h3 {
  margin-top: var(--space-8);
  margin-bottom: var(--space-3);
}

.prose p {
  margin-bottom: var(--space-4);
}

.prose ul, .prose ol {
  margin-bottom: var(--space-4);
  padding-left: var(--space-6);
}

.prose li {
  margin-bottom: var(--space-2);
  color: var(--color-text-secondary);
  list-style: disc;
}

.prose blockquote {
  border-left: 3px solid var(--color-accent);
  padding: var(--space-4) var(--space-6);
  margin: var(--space-6) 0;
  background: var(--color-bg-secondary);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border-radius: 0 var(--border-radius) var(--border-radius) 0;
  font-style: italic;
  color: var(--color-text-secondary);
}

/* --- Disclaimer box --- */
.disclaimer {
  border: 1px solid var(--color-warning);
  background: rgba(210, 153, 34, 0.06);
  border-radius: var(--border-radius);
  padding: var(--space-4) var(--space-6);
  margin: var(--space-6) 0;
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
}

.disclaimer strong {
  color: var(--color-warning);
}