:root {
  --bg: #efefed;
  --panel: rgba(255,255,255,.90);
  --text: #171717;
  --muted: #777;
  --line: rgba(0,0,0,.12);
  --red: #e32620;
}

* {
  box-sizing: border-box;
}

html,
body {
  width: 100%;
  height: 100%;
  margin: 0;
  overflow: hidden;

  font-family:
    -apple-system,
    BlinkMacSystemFont,
    "Segoe UI",
    Helvetica,
    Arial,
    sans-serif;

  background: var(--bg);
  color: var(--text);
}

button,
input,
select {
  font: inherit;
}

button {
  border: 0;
}

canvas {
  display: block;
  touch-action: none;
}


/* ======================================================
   START SCREEN
====================================================== */

#startScreen {
  position: fixed;
  inset: 0;
  z-index: 100;

  display: grid;
  place-items: center;

  background: #fff;

  transition:
    opacity .35s ease,
    visibility .35s ease;
}

#startScreen.hidden {
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

.drop-card {
  width: min(520px, calc(100vw - 40px));
  padding: 42px 34px;

  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;

  text-align: center;

  border: 1px solid var(--line);
  border-radius: 18px;

  background: #fff;
  box-shadow: 0 24px 50px rgba(0,0,0,.24);

  transition:
    transform .15s ease,
    background .15s ease;
}

body.dragging .drop-card {
  transform: scale(1.015);
  background: white;
}

.logo {
  margin-bottom: 42px;

  font-size: 13px;
  font-weight: 700;
  letter-spacing: .18em;
}

.drop-title {
  margin-bottom: 12px;

  font-size: clamp(28px,5vw,44px);
  line-height: 1.03;
  letter-spacing: -.04em;
}

.drop-subtitle {
  margin-bottom: 28px;

  color: var(--muted);
  font-size: 15px;
}

.drop-action {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 14px;

  font-size: 16px;
}

.open-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;

  min-width: 150px;
  height: 46px;

  padding: 0 22px;

  border-radius: 23px;

  background: #111;
  color: white;

  font-size: 15px;
  font-weight: 500;
  letter-spacing: .08em;

  cursor: pointer;
}

.open-button:hover {
  opacity: .82;
}


/* ======================================================
   VIEWER UI
====================================================== */

#viewerUI {
  position: fixed;
  inset: 0;
  z-index: 20;

  pointer-events: none;
}

#topbar {
  position: absolute;

  top: 16px;
  left: 16px;
  right: 16px;

  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto auto;
  gap: 10px;
  align-items: flex-start;

  pointer-events: none;
}

.brand,
.brand-group,
.style-toolbar,
.view-toolbar,
.controls-button,
.panel {
  pointer-events: auto;
}

.brand {
  border: 0;

  padding: 10px 14px;

  border-radius: 10px;

  background: var(--panel);
  backdrop-filter: blur(14px);

  font-size: 12px;
  font-weight: 700;
  letter-spacing: .12em;

  cursor: pointer;
}

.brand-group {
  display: flex;
  align-items: center;
  gap: 10px;
}

.brand-credit {
  color: #777;
  font-size: 11px;
  letter-spacing: .04em;
  white-space: nowrap;
}

.style-toolbar,
.view-toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;

  gap: 5px;
}

.style-toolbar {
  justify-content: center;
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
}

.view-toolbar {
  justify-content: flex-end;
}

.controls-button {
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .12em;
  text-transform: uppercase;
}

.tool-button {
  min-height: 36px;

  padding: 0 12px;

  border-radius: 8px;

  background: var(--panel);
  backdrop-filter: blur(14px);

  cursor: pointer;

  color: #222;
}

.tool-button:hover {
  background: white;
}

.tool-button.active {
  background: #111;
  color: white;
}

.tool-button.red.active {
  background: var(--red);
}


/* ======================================================
   SIDE PANEL
====================================================== */

#sidePanel {
  position: absolute;

  top: 66px;
  right: 16px;

  width: 280px;
  max-height: calc(100vh - 100px);

  overflow: auto;

  padding: 15px;

  border-radius: 12px;

  background: var(--panel);
  backdrop-filter: blur(16px);

  pointer-events: auto;

  transition:
    opacity .2s ease,
    transform .2s ease;
}

#sidePanel.hidden {
  opacity: 0;
  transform: translateX(12px);
  pointer-events: none;
}

.panel-section + .panel-section {
  border-top: 1px solid var(--line);

  margin-top: 15px;
  padding-top: 15px;
}

.panel-title {
  margin-bottom: 10px;

  font-size: 11px;
  font-weight: 700;

  letter-spacing: .1em;
  text-transform: uppercase;
}

.panel-section.disabled {
  opacity: .42;
}

.panel-section.disabled input {
  cursor: not-allowed;
}

.row {
  display: flex;
  align-items: center;
  justify-content: space-between;

  gap: 10px;

  margin: 8px 0;

  font-size: 13px;
}

.row label {
  color: #555;
}

.row input[type="range"] {
  width: 145px;
}

.color-row {
  align-items: flex-start;
}

.section-colors {
  display: grid;
  grid-template-columns: repeat(6, 16px);
  gap: 5px;
}

.color-swatch {
  width: 16px;
  height: 16px;
  padding: 0;
  border: 1px solid rgba(0,0,0,.16);
  border-radius: 4px;
  background: var(--swatch);
  cursor: pointer;
}

.color-swatch.active {
  border: 2px solid #111;
  box-shadow: 0 0 0 1px white;
}

.hidden-section-control {
  display: none;
}

.axis-buttons {
  display: grid;
  grid-template-columns: repeat(3,1fr);

  gap: 5px;
}

.axis-buttons button {
  padding: 8px;

  border-radius: 6px;

  cursor: pointer;

  background: #ddd;
}

.axis-buttons button.active {
  background: var(--red);
  color: white;
}

.model-stat {
  display: flex;
  justify-content: space-between;

  padding: 3px 0;

  font-size: 12px;
}

.material-list {
  max-height: 180px;
  overflow: auto;
}

.material-item {
  padding: 4px 0;

  border-bottom: 1px solid rgba(0,0,0,.05);

  font-size: 11px;
}

.navigation-hint {
  margin-top: 15px;
  padding-top: 12px;

  border-top: 1px solid var(--line);

  color: #888;
  font-size: 11px;
  text-align: center;
}

.support-link {
  display: block;
  margin-top: 9px;

  color: #777;
  font-size: 11px;
  text-align: center;
  text-decoration: none;
}

.support-link:hover {
  color: #222;
  text-decoration: underline;
}

.section-debug-stats {
  margin-top: 10px;
  padding: 9px 10px;

  border-radius: 6px;

  background: rgba(0,0,0,.045);

  font-family:
    ui-monospace,
    SFMono-Regular,
    Menlo,
    Consolas,
    monospace;
  font-size: 10px;
  line-height: 1.55;
  color: #444;
}

.section-debug-stats:empty {
  display: none;
}


/* ======================================================
   MOBILE
====================================================== */

@media (max-width:720px) {

  #topbar {
    top: max(10px,env(safe-area-inset-top));
    left: 10px;
    right: 10px;
  }

  .brand {
    display: none;
  }

  .brand-group {
    display: none;
  }

  #topbar {
    grid-template-columns: 1fr;
    gap: 6px;
  }

  .style-toolbar,
  .view-toolbar,
  .controls-button {
    justify-self: end;
  }

  .style-toolbar {
    position: static;
    transform: none;
  }

  .tool-button {
    min-height: 34px;

    padding: 0 10px;

    font-size: 12px;
  }

  #sidePanel {
    top: auto;
    left: 10px;
    right: 10px;

    bottom: max(10px,env(safe-area-inset-bottom));

    width: auto;
    max-height: 45vh;
  }

}