/* ==========================================================================
   VOSTOK RX — FUTURISTIC TECH THEME (SUI.IO INSPIRED)
   ========================================================================== */
:root {
  --bg-dark: #010813;
  --bg-card: rgba(255, 255, 255, 0.01);
  --color-text-primary: #ffffff;
  --color-text-secondary: #8e9ba5;
  --color-border: rgba(0, 240, 255, 0.08);
  --neon-cyan: #00f0ff;
  --neon-blue: #298dff;
  --neon-orange: #e65c00;
  
  --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-heading: 'Plus Jakarta Sans', sans-serif;
  
  --mouse-x: 50%;
  --mouse-y: 50%;
  
  --transition-smooth: all 0.3s cubic-bezier(0.2, 0.8, 0.2, 1);
}

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

html {
  scroll-behavior: smooth;
  background-color: var(--bg-dark);
}

body {
  background-color: var(--bg-dark);
  color: var(--color-text-secondary);
  font-family: var(--font-primary);
  font-size: 15px;
  line-height: 1.6;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

/* ==========================================================================
   SUI-STYLE SPOTLIGHT GRADIENT BLUR
   ========================================================================== */
.gradient-blur {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 50; /* Above normal content, below header & canvas */
}

.gradient-blur > div {
  position: absolute;
  inset: 0;
  transform: translate3d(0, 0, 0);
  backface-visibility: hidden;
  will-change: mask-image, -webkit-mask-image;
}

/* Three overlapping layers of progressive blur with radial masks */
.gradient-blur > div:nth-of-type(1) {
  backdrop-filter: blur(2.5px);
  -webkit-backdrop-filter: blur(2.5px);
  mask: radial-gradient(circle at var(--mouse-x) var(--mouse-y), transparent 0%, transparent 12%, black 18%);
  -webkit-mask: radial-gradient(circle at var(--mouse-x) var(--mouse-y), transparent 0%, transparent 12%, black 18%);
}

.gradient-blur > div:nth-of-type(2) {
  backdrop-filter: blur(5px);
  -webkit-backdrop-filter: blur(5px);
  mask: radial-gradient(circle at var(--mouse-x) var(--mouse-y), transparent 0%, transparent 14%, black 32%);
  -webkit-mask: radial-gradient(circle at var(--mouse-x) var(--mouse-y), transparent 0%, transparent 14%, black 32%);
}

.gradient-blur > div:nth-of-type(3) {
  backdrop-filter: blur(9px);
  -webkit-backdrop-filter: blur(9px);
  mask: radial-gradient(circle at var(--mouse-x) var(--mouse-y), transparent 0%, transparent 18%, black 48%);
  -webkit-mask: radial-gradient(circle at var(--mouse-x) var(--mouse-y), transparent 0%, transparent 18%, black 48%);
}

/* Cyber Grid Background lines */
.cyber-grid {
  position: fixed;
  inset: 0;
  background-size: 60px 60px;
  background-image: 
    linear-gradient(to right, rgba(0, 240, 255, 0.015) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(0, 240, 255, 0.015) 1px, transparent 1px);
  z-index: 1;
  pointer-events: none;
}

/* ==========================================================================
   NAVIGATION HEADER
   ========================================================================== */
#main-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 80px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0 48px;
  background-color: rgba(1, 8, 19, 0.65);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  z-index: 100; /* Keep active navbar above the blur! */
}

.logo {
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 1.3rem;
  letter-spacing: 0.05em;
  color: var(--color-text-primary);
}

.logo-accent {
  color: var(--neon-cyan);
  text-shadow: 0 0 10px rgba(0, 240, 255, 0.4);
}

nav {
  display: flex;
  gap: 36px;
}

.nav-link {
  color: var(--color-text-secondary);
  font-family: var(--font-primary);
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  cursor: pointer;
  padding: 8px 0;
  position: relative;
  transition: var(--transition-smooth);
}

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

/* Selected indicator block (solid under-bar) */
.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0%;
  height: 2px;
  background-color: var(--neon-cyan);
  box-shadow: 0 0 8px var(--neon-cyan);
  transition: var(--transition-smooth);
}

nav[selected='about'] [data-id='about']::after,
nav[selected='classes'] [data-id='classes']::after,
nav[selected='showcase'] [data-id='showcase']::after,
nav[selected='contact'] [data-id='contact']::after {
  width: 100%;
}

nav[selected='about'] [data-id='about'],
nav[selected='classes'] [data-id='classes'],
nav[selected='showcase'] [data-id='showcase'],
nav[selected='contact'] [data-id='contact'] {
  color: var(--color-text-primary);
}

/* ==========================================================================
   VERTICAL LAYOUT SECTIONS
   ========================================================================== */
.content-wrapper {
  max-width: 1000px;
  margin: 0 auto;
  padding: 0 24px;
}

section {
  min-height: 100vh;
  padding: 140px 0;
  display: flex;
  flex-direction: column;
  justify-content: center;
  position: relative;
  z-index: 10; /* Sitting under the blur overlay */
}

.section-tag {
  font-family: monospace;
  font-size: 0.75rem;
  letter-spacing: 0.2em;
  color: var(--neon-cyan);
  text-shadow: 0 0 8px rgba(0, 240, 255, 0.25);
  margin-bottom: 24px;
}

.hero-title {
  font-family: var(--font-heading);
  font-size: 3.25rem;
  font-weight: 800;
  line-height: 1.15;
  color: var(--color-text-primary);
  letter-spacing: -0.02em;
  margin-bottom: 32px;
  max-width: 700px;
}

.section-title {
  font-family: var(--font-heading);
  font-size: 2.25rem;
  font-weight: 700;
  line-height: 1.2;
  color: var(--color-text-primary);
  margin-bottom: 48px;
}

.info-wrapper {
  max-width: 600px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.info-wrapper p {
  color: var(--color-text-secondary);
  font-size: 1rem;
}

.info-wrapper p strong {
  color: var(--color-text-primary);
}

/* ==========================================================================
   CLASSES CARD GRID (GLASSMORPHISM)
   ========================================================================== */
.classes-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.class-card {
  background: var(--bg-card);
  border: 1px solid var(--color-border);
  border-radius: 16px;
  padding: 36px;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  display: flex;
  flex-direction: column;
  gap: 16px;
  transition: var(--transition-smooth);
}

.class-card:hover {
  border-color: rgba(0, 240, 255, 0.25);
  background: rgba(0, 240, 255, 0.015);
  transform: translateY(-4px);
  box-shadow: 0 12px 30px rgba(0, 240, 255, 0.03);
}

.class-num {
  font-family: monospace;
  font-size: 0.85rem;
  color: var(--neon-cyan);
  font-weight: 700;
}

.class-card h3 {
  font-family: var(--font-heading);
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--color-text-primary);
}

.class-card p {
  font-size: 0.9rem;
  color: var(--color-text-secondary);
  line-height: 1.5;
}

/* ==========================================================================
   CONTACT CARD
   ========================================================================== */
.contact-card {
  background: var(--bg-card);
  border: 1px solid var(--color-border);
  border-radius: 16px;
  padding: 40px;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  display: flex;
  flex-direction: column;
  gap: 32px;
}

.contact-details {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.detail-item {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.detail-label {
  font-family: monospace;
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  color: var(--color-text-secondary);
}

.detail-val {
  font-size: 0.95rem;
  color: var(--color-text-primary);
  font-weight: 500;
}

.contact-links {
  display: flex;
  gap: 16px;
}

/* Sleek modern cyber buttons */
.cyber-btn {
  background: transparent;
  color: var(--color-text-primary);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08); /* Override default dotted border */
  border-radius: 8px;
  padding: 12px 24px;
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  transition: var(--transition-smooth);
  cursor: pointer;
}

.cyber-btn:hover {
  background: var(--color-text-primary);
  color: var(--bg-dark);
  border-color: var(--color-text-primary);
}

/* ==========================================================================
   FLOATING NEON CANVAS OVERLAY
   ========================================================================== */
#bg-canvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  z-index: 1000; /* Run athlete above the blur! */
  pointer-events: none;
  display: block;
}

/* ==========================================================================
   RESPONSIVE OVERRIDES
   ========================================================================== */
@media screen and (max-width: 900px) {
  #main-header {
    padding: 0 24px;
  }
  
  .hero-title {
    font-size: 2.5rem;
  }
  
  .classes-grid {
    grid-template-columns: 1fr;
  }
  
  .contact-details {
    grid-template-columns: 1fr;
    gap: 16px;
  }
}

@media screen and (max-width: 600px) {
  #main-header {
    flex-direction: column;
    height: auto;
    padding: 16px;
    gap: 12px;
  }
  
  nav {
    gap: 16px;
  }
  
  section {
    padding-top: 100px;
  }
}