/* ============================================================
   SDT WIREFRAME v2 — clean, client-readable
   Neutral sans-serif, no annotations, one accent.
   ============================================================ */

:root {
  --bg: #ededed;
  --paper: #ffffff;
  --ink: #1a1a1a;
  --ink-2: #4a4a4a;
  --ink-3: #8a8a8a;
  --ink-4: #c4c4c4;
  --line: #d4d4d4;
  --line-2: #1a1a1a;
  --rail: rgba(20, 20, 22, 0.92);
  --rail-fg: #f0f0f0;
  --rail-fg-dim: #8a8a8a;
  --accent: #0066b3;       /* SDT-ish blue */
  --accent-soft: #e6f1fa;
  --accent-ink: #ffffff;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: #2a2a2c;
  font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
  font-feature-settings: "kern" 1, "liga" 1;
  -webkit-font-smoothing: antialiased;
  color: var(--ink);
  overflow: hidden;
  height: 100vh;
  width: 100vw;
}

.app {
  height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px;
}

/* ----- 16:9 canvas ----- */
.canvas-frame {
  width: 1600px;
  height: 900px;
  position: relative;
  box-shadow: 0 24px 60px rgba(0,0,0,0.45);
  transform-origin: center center;
  overflow: hidden;
  /* Full-bleed immersive background placeholder */
  background: #d6d8da;
  background-image:
    repeating-linear-gradient(
      135deg,
      transparent 0,
      transparent 22px,
      rgba(0,0,0,0.04) 22px,
      rgba(0,0,0,0.04) 23px
    );
  transition: background 0.5s ease;
}

/* Levels: compact loop vs exploded loop — different bg pattern */
.canvas-frame.bg-levels-exploded {
  background-color: #cfd4d8;
  background-image:
    repeating-linear-gradient(
      45deg,
      transparent 0,
      transparent 18px,
      rgba(0,102,179,0.07) 18px,
      rgba(0,102,179,0.07) 19px
    );
}

/* Key Characteristics: each highlighted char gets its own bg loop */
.canvas-frame.bg-char-data {
  background-color: #cfd9e0;
  background-image:
    repeating-linear-gradient(
      90deg,
      transparent 0,
      transparent 20px,
      rgba(0,102,179,0.08) 20px,
      rgba(0,102,179,0.08) 21px
    );
}
.canvas-frame.bg-char-connectivity {
  background-color: #d0d6dc;
  background-image:
    repeating-linear-gradient(
      0deg,
      transparent 0,
      transparent 26px,
      rgba(0,102,179,0.08) 26px,
      rgba(0,102,179,0.08) 27px
    ),
    repeating-linear-gradient(
      90deg,
      transparent 0,
      transparent 26px,
      rgba(0,102,179,0.05) 26px,
      rgba(0,102,179,0.05) 27px
    );
}
.canvas-frame.bg-char-evolvability {
  background-color: #d4d8d4;
  background-image:
    repeating-linear-gradient(
      135deg,
      transparent 0,
      transparent 14px,
      rgba(0,102,179,0.07) 14px,
      rgba(0,102,179,0.07) 15px
    );
}

/* Corner tag describing the immersive bg for the current scene */
.bg-tag {
  position: absolute;
  top: 24px;
  right: 24px;
  background: rgba(26,26,26,0.85);
  color: #fff;
  font-size: 10px;
  padding: 4px 8px;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  font-weight: 500;
  z-index: 23;
  pointer-events: none;
}

/* ============================================================
   FLOATING CHROME — logo + home + airy left nav
   ============================================================ */

/* Persistent corner: Alstom logo + home button */
.chrome {
  position: absolute;
  top: 36px;
  left: 40px;
  z-index: 25;
  display: flex;
  align-items: center;
  gap: 10px;
}
.chrome .logo {
  /* Placeholder — client to drop the real Alstom logo here */
  width: 96px;
  height: 28px;
  border: 1px dashed var(--ink-2);
  background: rgba(255,255,255,0.55);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 11px;
  letter-spacing: 2px;
  color: var(--ink-2);
  font-weight: 500;
}
.chrome .home {
  width: 28px;
  height: 28px;
  border: 1px solid var(--ink-2);
  background: rgba(255,255,255,0.55);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  color: var(--ink);
  font-family: inherit;
  font-size: 14px;
  padding: 0;
}
.chrome .home:hover {
  background: var(--ink);
  color: #fff;
  border-color: var(--ink);
}

/* Airy left navigation — overlays the scene, no background */
.nav-airy {
  position: absolute;
  left: 40px;
  top: 50%;
  transform: translateY(-50%);
  z-index: 22;
  display: flex;
  flex-direction: column;
  gap: 10px;
  /* let scene receive events except on the items */
  pointer-events: none;
}
.nav-item {
  pointer-events: auto;
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 6px 0;
  background: transparent;
  border: 0;
  font-family: inherit;
  font-size: 13px;
  letter-spacing: 0.3px;
  color: var(--ink-3);
  cursor: pointer;
  text-align: left;
  position: relative;
  transition: color 0.15s, transform 0.15s;
}
.nav-item:hover { color: var(--ink); }
.nav-item .ni-bar {
  width: 18px;
  height: 1px;
  background: var(--ink-3);
  transition: width 0.2s, background 0.2s;
  flex-shrink: 0;
}
.nav-item:hover .ni-bar { background: var(--ink); }
.nav-item .ni-num {
  font-size: 10px;
  letter-spacing: 1.5px;
  font-variant-numeric: tabular-nums;
  width: 20px;
  color: inherit;
}
.nav-item .ni-label {
  white-space: nowrap;
}
.nav-item.active {
  color: var(--ink);
}
.nav-item.active .ni-bar {
  width: 32px;
  background: var(--accent);
  height: 1.5px;
}
.nav-item.active .ni-label {
  font-weight: 600;
}

/* Scene container — full canvas, content shifts right when nav is shown */
.scene {
  position: absolute;
  left: 220px;
  top: 0;
  right: 0;
  bottom: 0;
  overflow: hidden;
}
.scene.full {
  left: 0;
}

/* ============================================================
   PRIMITIVES
   ============================================================ */

/* Video / immersive placeholder */
.placeholder {
  position: absolute;
  background: #d6d8da;
  background-image:
    repeating-linear-gradient(
      135deg,
      transparent 0,
      transparent 22px,
      rgba(0,0,0,0.04) 22px,
      rgba(0,0,0,0.04) 23px
    );
  border: 1px solid var(--ink-4);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  text-align: center;
  color: var(--ink-3);
  padding: 12px;
  font-size: 12px;
  letter-spacing: 0.5px;
}
.placeholder .ph-tag {
  position: absolute;
  top: 10px;
  left: 10px;
  background: rgba(26,26,26,0.85);
  color: #fff;
  font-size: 10px;
  padding: 3px 7px;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  font-weight: 500;
}
.placeholder .ph-label {
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  color: var(--ink-2);
  font-weight: 500;
}
.placeholder .ph-desc {
  font-size: 11px;
  color: var(--ink-3);
  margin-top: 6px;
  max-width: 70%;
  letter-spacing: 0.2px;
}

/* Wireframe surfaces */
.wf-box {
  position: absolute;
  border: 1px solid var(--line-2);
  background: var(--paper);
}
.wf-box.dashed { border-style: dashed; }
.wf-box.soft { border-color: var(--line); }

/* ----- Buttons ----- */
.wf-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  border: 1px solid var(--ink);
  background: var(--paper);
  color: var(--ink);
  font-family: inherit;
  font-size: 13px;
  font-weight: 500;
  padding: 10px 18px;
  cursor: pointer;
  letter-spacing: 0.3px;
  position: relative;
  white-space: nowrap;
  transition: background 0.12s, color 0.12s;
}
.wf-btn:hover {
  background: var(--ink);
  color: var(--paper);
}
.wf-btn.primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
  font-size: 14px;
  padding: 12px 22px;
}
.wf-btn.primary:hover {
  background: #004d87;
  border-color: #004d87;
}
.wf-btn.ghost {
  background: transparent;
  border-color: var(--ink-4);
  color: var(--ink-2);
}
.wf-btn.ghost:hover {
  border-color: var(--ink);
  background: var(--paper);
  color: var(--ink);
}
.wf-btn.icon {
  width: 38px;
  height: 38px;
  padding: 0;
  font-size: 14px;
}
.wf-btn.lg {
  font-size: 15px;
  padding: 15px 28px;
}

/* ----- Typography ----- */
.wf-title {
  font-size: 32px;
  font-weight: 600;
  letter-spacing: -0.3px;
  margin: 0;
  line-height: 1.15;
  color: var(--ink);
}
.wf-subtitle {
  font-size: 16px;
  font-weight: 400;
  color: var(--ink-2);
  margin: 0;
  line-height: 1.4;
}
.wf-body {
  font-size: 13px;
  color: var(--ink-2);
  line-height: 1.55;
}
.wf-eyebrow {
  font-size: 10px;
  letter-spacing: 1.8px;
  text-transform: uppercase;
  color: var(--ink-3);
  font-weight: 500;
}

/* Placeholder text bars */
.txt-bar {
  height: 8px;
  background: var(--ink-4);
  opacity: 0.6;
  border-radius: 1px;
}

/* ----- Popups ----- */
.popup {
  position: absolute;
  background: var(--paper);
  border: 1px solid var(--ink);
  box-shadow: 0 14px 40px rgba(0,0,0,0.18);
  padding: 24px;
  z-index: 30;
}
.popup .close {
  position: absolute;
  top: 12px;
  right: 12px;
  width: 28px;
  height: 28px;
  border: 1px solid var(--line);
  background: var(--paper);
  font-family: inherit;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  color: var(--ink-2);
}
.popup .close:hover {
  border-color: var(--ink);
  color: var(--ink);
}
.popup-eyebrow {
  font-size: 10px;
  letter-spacing: 1.8px;
  color: var(--ink-3);
  text-transform: uppercase;
  margin-bottom: 6px;
  font-weight: 500;
}

/* ----- Sliders ----- */
.h-slider {
  position: absolute;
  height: 44px;
  display: flex;
  align-items: center;
  cursor: pointer;
  user-select: none;
}
.h-slider .track {
  position: absolute;
  left: 0; right: 0;
  height: 4px;
  background: var(--ink-4);
}
.h-slider .track-fill {
  position: absolute;
  height: 4px;
  background: var(--accent);
  left: 0;
}
.h-slider .handle {
  position: absolute;
  width: 32px;
  height: 32px;
  background: var(--paper);
  border: 1.5px solid var(--ink);
  border-radius: 50%;
  transform: translate(-50%, -50%);
  top: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: grab;
  font-size: 11px;
  color: var(--ink-2);
}
.h-slider .handle:active { cursor: grabbing; background: var(--accent); color: #fff; border-color: var(--accent); }
.h-slider .tick {
  position: absolute;
  top: 50%;
  width: 1px;
  height: 12px;
  background: var(--ink-4);
  transform: translate(-50%, -50%);
}

.v-slider {
  position: absolute;
  width: 44px;
  display: flex;
  justify-content: center;
  cursor: pointer;
  user-select: none;
}
.v-slider .track {
  position: absolute;
  top: 0; bottom: 0;
  width: 4px;
  background: var(--ink-4);
}
.v-slider .track-fill {
  position: absolute;
  width: 4px;
  background: var(--accent);
  left: 50%;
  transform: translateX(-50%);
}
.v-slider .handle {
  position: absolute;
  width: 32px;
  height: 32px;
  background: var(--paper);
  border: 1.5px solid var(--ink);
  border-radius: 50%;
  transform: translate(-50%, -50%);
  left: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: grab;
  font-size: 11px;
  color: var(--ink-2);
}
.v-slider .handle:active { cursor: grabbing; background: var(--accent); color: #fff; border-color: var(--accent); }

/* ----- Misc ----- */
.chip {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 10px;
  padding: 3px 8px;
  border: 1px solid var(--line);
  background: var(--paper);
  color: var(--ink-2);
  letter-spacing: 0.5px;
  text-transform: uppercase;
  font-weight: 500;
}
.chip.accent { background: var(--accent); border-color: var(--accent); color: #fff; }
.chip.soft { background: var(--accent-soft); border-color: var(--accent); color: var(--accent); }

.numdot {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  border: 1px solid var(--ink);
  background: var(--paper);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 11px;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  color: var(--ink);
}
.numdot.active { background: var(--accent); border-color: var(--accent); color: #fff; }

/* Video player */
.video-controls {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 18px;
  border-top: 1px solid var(--line);
  background: var(--paper);
}
.scrubber {
  flex: 1;
  height: 4px;
  background: var(--ink-4);
  position: relative;
  cursor: pointer;
}
.scrubber .fill {
  position: absolute;
  left: 0; top: 0; bottom: 0;
  background: var(--accent);
  width: 35%;
}
.scrubber .knob {
  position: absolute;
  top: 50%;
  left: 35%;
  width: 12px;
  height: 12px;
  background: var(--ink);
  border-radius: 50%;
  transform: translate(-50%, -50%);
}

/* Connecting line SVG for key chars */
.connect-svg {
  position: absolute;
  inset: 0;
  pointer-events: none;
  z-index: 1;
}

/* Pillars */
.pillar {
  border: 1px solid var(--ink);
  background: var(--paper);
  display: flex;
  flex-direction: column;
  align-items: stretch;
  padding: 18px 16px;
  cursor: pointer;
  transition: all 0.25s ease;
  position: relative;
}
.pillar.active {
  background: var(--accent-soft);
  border-color: var(--accent);
}
.pillar.dim { opacity: 0.55; }
.pillar:hover:not(.active) {
  border-color: var(--accent);
}

.pillar-num {
  font-size: 11px;
  letter-spacing: 1.5px;
  color: var(--ink-3);
  margin-bottom: 14px;
}
.pillar-label {
  font-size: 20px;
  font-weight: 600;
  writing-mode: vertical-rl;
  transform: rotate(180deg);
  margin: auto;
  letter-spacing: 0.3px;
}
.pillar.active .pillar-label {
  writing-mode: horizontal-tb;
  transform: none;
  font-size: 26px;
  margin: 0 0 14px 0;
}

/* Use case tile */
.uc-tile {
  border: 1px solid var(--ink);
  background: var(--paper);
  padding: 16px;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  gap: 14px;
  transition: border-color 0.12s, transform 0.15s;
  position: relative;
}
.uc-tile:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}
.uc-tile .uc-thumb {
  height: 110px;
  position: relative;
  flex-shrink: 0;
}
.uc-tile .uc-thumb .play-icon {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 22px;
  color: var(--ink-2);
}

/* Layer card (screen 2 exploded) */
.layer-card {
  border: 1px solid var(--ink);
  background: var(--paper);
  padding: 16px 22px;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  gap: 6px;
  transition: all 0.2s;
  position: relative;
}
.layer-card:hover { border-color: var(--accent); }
.layer-card.active {
  background: var(--accent-soft);
  border-color: var(--accent);
}

/* Transition full overlay (during nav) */
.transition-overlay {
  position: absolute;
  inset: 0;
  z-index: 50;
  pointer-events: none;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #000;
}
.transition-overlay.forward {
  animation: tover 0.6s ease both;
}
.transition-overlay.reverse {
  animation: toverR 0.6s ease both;
}
.transition-overlay.shader {
  background:
    repeating-linear-gradient(0deg, transparent 0, transparent 4px, rgba(0,102,179,0.45) 4px, rgba(0,102,179,0.45) 5px),
    repeating-linear-gradient(90deg, transparent 0, transparent 4px, rgba(255,255,255,0.06) 4px, rgba(255,255,255,0.06) 5px),
    #050a14;
  animation: tshader 0.6s ease both;
}
@keyframes tover {
  0% { transform: translateX(100%); }
  50% { transform: translateX(0); }
  100% { transform: translateX(-100%); }
}
@keyframes toverR {
  0% { transform: translateX(-100%); }
  50% { transform: translateX(0); }
  100% { transform: translateX(100%); }
}
@keyframes tshader {
  0% { opacity: 0; }
  50% { opacity: 1; }
  100% { opacity: 0; }
}

/* Utilities */
.stack { display: flex; flex-direction: column; }
.row { display: flex; align-items: center; }