:root {
  --accent: #0cc;
  --accent-rgb: 0, 204, 204;
}

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

html, body {
  background: #000;
  color: #fff;
  font-family: 'Share Tech Mono', monospace;
  overflow-x: hidden;
}

h1, h2 {
  font-family: 'Major Mono Display', monospace;
}

/* -- Canvas container -------------------------------------------------- */
#canvas-container {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
}

#canvas-container canvas { display: block; }

/* -- Runway (scroll spacer) -------------------------------------------- */
#runway {
  position: relative;
  pointer-events: none;
}

#runway-buffer {
  position: relative;
  height: 80vh;
  pointer-events: none;
}

/* -- Nav button override (safe-area + z-index) ------------------------- */
.nav-btn {
  top: max(16px, env(safe-area-inset-top, 0px));
  z-index: 100;
}

/* -- Progress bar ------------------------------------------------------ */
#progress-bar {
  position: fixed;
  top: 0;
  left: 0;
  height: 2px;
  background: var(--accent);
  z-index: 200;
  width: 0;
}

/* -- Scroll hint ------------------------------------------------------- */
#scroll-hint {
  position: fixed;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 100;
  text-align: center;
  font-size: 18px;
  color: rgba(255, 255, 255, 0.4);
  transition: opacity 0.6s;
}

#scroll-hint .arrow {
  display: block;
  margin-top: 4px;
  animation: bounce 2s ease-in-out infinite;
}

@keyframes bounce {
  0%, 100% { transform: translateY(0); }
  50%      { transform: translateY(6px); }
}

/* -- Header panel ------------------------------------------------------ */
#header-panel {
  position: fixed;
  top: 4%;
  left: 50%;
  transform: translateX(-50%);
  z-index: 15;
  pointer-events: none;
  background: rgba(0, 0, 0, 0.5);
  border-radius: 16px;
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  text-align: center;
  transition: opacity 0.4s ease;
}

/* -- Tech subtitle ----------------------------------------------------- */
#tech-subtitle {
  font-family: 'Major Mono Display', monospace;
  font-size: clamp(20px, 3vw, 32px);
  color: rgba(255, 255, 255, 0.35);
  letter-spacing: 0.15em;
  font-weight: bold;
  margin-top: 8px;
  opacity: 0;
}

/* -- Tech content container -------------------------------------------- */
#tech-content {
  position: relative;
  z-index: 11;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 32px 24px;
  background: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border: 1px solid rgba(255, 255, 255, 0.06);
  border-radius: 16px;
  margin-bottom: 4vh;
}

/* -- Row grid system --------------------------------------------------- */
.rows {
  display: flex;
  flex-direction: column;
  gap: 32px;
  padding: 16px 0;
}

.row {
  display: grid;
  grid-template-columns: 42% 1fr;
  grid-template-rows: auto 1fr;
  align-items: center;
  gap: 0 40px;
  opacity: 0;
  transform: translateY(24px);
}

.row-title {
  grid-column: 2;
  grid-row: 1;
  font-family: 'Major Mono Display', monospace;
  font-size: clamp(18px, 2.2vw, 26px);
  color: var(--accent);
  margin-bottom: 8px;
}

.row-visual {
  grid-column: 1;
  grid-row: 1 / -1;
  display: flex;
  align-items: center;
  justify-content: center;
}

.row-text {
  grid-column: 2;
  grid-row: 2;
}

.row--reverse {
  grid-template-columns: 1fr 42%;
}

.row--reverse .row-title  { grid-column: 1; }
.row--reverse .row-visual { grid-column: 2; }
.row--reverse .row-text   { grid-column: 1; }

/* -- Row text list ----------------------------------------------------- */
.row-text ul {
  list-style: none;
  padding: 0;
}

.row-text li {
  font-size: clamp(15px, 1.4vw, 18px);
  line-height: 1.6;
  color: rgba(255, 255, 255, 0.8);
  padding-left: 20px;
  position: relative;
  margin-bottom: 6px;
}

.row-text li::before {
  content: '\25B8';
  position: absolute;
  left: 0;
  color: rgba(var(--accent-rgb), 0.5);
}

/* -- Architecture SVG -------------------------------------------------- */
.arch-svg {
  width: 100%;
  max-width: 440px;
  height: auto;
}

.arch-node {
  fill: rgba(var(--accent-rgb), 0.08);
  stroke: rgba(var(--accent-rgb), 0.4);
  stroke-width: 1.5;
}

.arch-label {
  fill: var(--accent);
  font-family: 'Share Tech Mono', monospace;
  font-size: 20px;
  text-anchor: middle;
  dominant-baseline: central;
}

.arch-line {
  stroke: rgba(var(--accent-rgb), 0.45);
  stroke-width: 2;
  stroke-dasharray: 10 7;
  animation: dash-flow 2s linear infinite;
}

.arch-hub-glow {
  animation: hub-glow 2s ease-in-out infinite;
}

@keyframes dash-flow {
  to { stroke-dashoffset: -14; }
}

@keyframes hub-glow {
  0%, 100% { opacity: 0.3; }
  50%      { opacity: 1; }
}

/* -- Tooltip ----------------------------------------------------------- */
#tooltip {
  position: absolute;
  left: 0;
  z-index: 20;
  background: rgba(0, 0, 0, 0.85);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border: 1px solid rgba(var(--accent-rgb), 0.3);
  border-radius: 8px;
  padding: 10px 14px;
  color: #fff;
  font-size: 16px;
  line-height: 1.5;
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.2s;
  white-space: nowrap;
  transform: translateY(-100%) translateY(-8px);
}

#tooltip.visible { opacity: 1; }

.tooltip-name {
  color: var(--accent);
  font-style: italic;
  font-size: 18px;
  margin-bottom: 4px;
}

.tooltip-pos { color: #4f8; }
.tooltip-neg { color: #f64; }

/* -- Toggle buttons ---------------------------------------------------- */
.pref-btn,
.flow-btn {
  background: rgba(0, 0, 0, 0.4);
  border: 1px solid rgba(255, 255, 255, 0.15);
  color: rgba(255, 255, 255, 0.5);
  font-family: 'Share Tech Mono', monospace;
  font-size: clamp(14px, 1.3vw, 17px);
  padding: 10px 14px;
  min-height: 44px;
  border-radius: 4px;
  cursor: pointer;
  transition: border-color 0.3s, color 0.3s, box-shadow 0.3s;
}

.pref-btn:hover,
.flow-btn:hover {
  color: rgba(255, 255, 255, 0.8);
  border-color: rgba(255, 255, 255, 0.3);
}

.pref-btn.active,
.flow-btn.active {
  color: #fff;
  border-color: var(--accent);
  box-shadow: 0 0 8px rgba(var(--accent-rgb), 0.3);
}

.pref-btn:focus-visible,
.flow-btn:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* -- Tech footer ------------------------------------------------------- */
.tech-footer {
  padding: 20px 0 24px;
  text-align: center;
  font-size: clamp(14px, 1.3vw, 16px);
  color: rgba(255, 255, 255, 0.35);
  opacity: 0;
  transform: translateY(24px);
}

.tech-footer span {
  color: rgba(var(--accent-rgb), 0.5);
}

/* -- Responsive: tech content collapse --------------------------------- */
@media (max-width: 800px) {
  #tech-content { padding: 0 20px 16px; }
  .row, .row--reverse {
    display: flex;
    flex-direction: column;
    gap: 16px;
  }
  .row-title { order: 1; }
  .row-visual {
    order: 2;
    width: 100%;
    max-width: 320px;
  }
  .row-text { order: 3; }
  .rows { gap: 40px; padding: 24px 0; }
}

/* -- Responsive: touch device ------------------------------------------ */
@media (hover: none) {
  .nav-btn,
  #header-panel,
  #tooltip {
    background: rgba(0, 0, 0, 0.75);
    backdrop-filter: none;
    -webkit-backdrop-filter: none;
  }
  #tech-content {
    background: rgba(0, 0, 0, 0.85);
    backdrop-filter: none;
    -webkit-backdrop-filter: none;
  }
}

/* -- Responsive: mid-small (400–600px gap) ----------------------------- */
@media (max-width: 480px) {
  #tooltip {
    white-space: normal;
    max-width: 90vw;
  }
}

/* -- Responsive: small header ------------------------------------------ */
@media (max-width: 600px) {
  #header-panel {
    padding: 16px 20px 12px;
    max-width: 94vw;
    top: 68px;
  }
}

/* -- Reduced motion ---------------------------------------------------- */
@media (prefers-reduced-motion: reduce) {
  .arch-line { animation: none; }
  .arch-hub-glow { animation: none; opacity: 0.6; }
  #scroll-hint .arrow { animation: none; }
}