:root {
  --bottom-bar-h: 3rem;
    
    /* base colors */
  --bg-color: #f5f5f5;
  --text-color: #111;
  
    /* buttons */
  --button-bg: #000;
  --button-text: #fff;
  --button-disabled: #222;
  --button-hover: #666;
  --bg-toggle: #bbb;
  --outline-toggle: #aaa;
  
    /* panels and labels */
  --panel-bg: #ddd;  
  --label-bg: #000;
  --label-text: #fff;
  --label-disabled: #888;
  
    /* viewer */
  --viewer-bg: #cccccc;
  
    /* hamburger */
  --ham-color: #000000;
  --ham-hover: 0.2;
  }
  
body.dark-mode {
 --bg-color: #111;
  --text-color: #eee;
  
  --button-bg: #666;
  --button-text: #fff;
  --button-disabled: #444;
  --button-hover: #555;
  --bg-toggle: #bbb;
  --outline-toggle: #bbb;
  
  --panel-bg: #333;
  --label-bg: #666;
  --label-text: #fff;
  --label-disabled: #444;
  
  --viewer-bg: #242424;
  
  --ham-color: #ffffff;
  --ham-hover: 0.4;
  }

body.dark-mode .side-logo {
filter: invert(0.6) brightness(0.7);
}

/* reset and global box-sizing */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

/* full bleed layout and safe area inserts */

html, body {
  width: 100%;
  height: 100%;
  font-family: sans-serif;
  overflow: hidden;
  overflow-x: hidden;
}

body {
  padding-bottom: env(safe-area-inset-bottom);
  padding-top: env(safe-area-inset-top);
  padding-left: env(safe-area-inset-left);
  padding-right: env(safe-area-inset-right);
  background-color: var(--bg-color);
  color: var(--text-color);
}

.hidden {
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.5s ease;
  display: none !important;
  }
  
.quit-screen {
  height: 100vh;
  width: 100vw;
  background: url('/images/logo.png') no-repeat center center / contain;
  background-color: black;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  color: white;
  text-shadow: 0 0 5px black;
  font-family: Arial, sans-serif;
  }

#splash-screen {
  position: fixed;
  inset: 0;
  width: 100vw;
  height: 100vh;
  height: 100dvh;
  z-index: 9999;
  background-image: url('/images/logo.png');
  background-size: contain; /* cover */
  background-repeat: no-repeat;
  background-position: center;
  background-color: black;
  display: flex;
  justify-content: center;
  align-items: center;
  opacity: 1;
  transition: opacity 1s ease-in-out, visibility 0s linear 1s;
  z-index: 9999;
  }

#start-btn {
  position: absolute;        /* stay in main app */
  bottom: 20%;
  left: 50%;
  transform: translateX(-50%);
  z-index: 10000;            /* above splash */
  padding: 0.75rem 2rem;
  font-size: 1.1rem;
  font-weight: bold;
  color: white;
  background: transparent;
  border: 2px solid white;
  border-radius: 6px;
  cursor: pointer;
  opacity: 0;
  transition: opacity 0.5s ease;
  pointer-events: auto;
}

#resume-audio-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background-color: rgba(0,0,0,0.7);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 9999;
  text-align: center;
  color: white;
  font-size: 1.5rem;
  padding: 1rem;
  }

#resume-audio-overlay {
  pointer-events: auto;
  }
  
#resume-audio-overlay.hidden {
  display: none;
  }
  
.fade-out {
  opacity: 0;
  transition: opacity 1s ease;
  pointer-events: none;
  }
  
.splash-overlay {
  text-align: center;
  color: white;
  background: rgba(0,0,0,0.5);
  padding: 30px;
  border-radius: 10px;
  color: white;
  font-size: 1.2rem;
  pointer-events: none;
  }

.spinner-svg {
  animation: rotate 2s linear infinite;
  width: 40px;
  height: 40px;
  margin: 20px auto;
  display: block;
  }

.spinner-svg .path {
stroke: white;
stroke-linecap: round;
stroke-width: 6;
animation: dash 1.5s ease-in-out infinite;
}

@keyframes rotate {
100% {
  transform: rotate(360deg);
  }
}

@keyframes dash {
0% {
  stroke-dasharray: 1, 150;
  stroke-dashoffset: 0;
  }
50% {
  stroke-dasharray: 90, 150;
  stroke-dashoffset: -35;
  }
100% {
  stroke-dasharray: 90, 150;
  stroke-dashoffset: -124;
  }  
}
  
/* App wrapper */
.app {
  display: flex;
  flex-direction: column;
  height: 100%;
  background: var(--bg-color);
}

/* pressure indicator*/
.pressure-btn {
  display: inline-block;
  text-align: center;
  padding: 0.75rem 1rem;
  font-size: clamp(0.875rem, 1.5vw, 1.125rem);
  
  background-color: var(--button-bg);
  color: var(--button-text);
  border: none;
  border-radius: 0;
  transition: background-color 0.1s ease;
  box-sizing: border-box;
  user-select: none;
  pointer-events: none;
  }

/* Top centered label */
#object-label, #nerve-label {
  position: absolute;
  top: 1rem;
  left: calc(50% + (env(safe-area-inset-left) - env(safe-area-inset-right))/2);
  transform: translateX(-50%);
  background-color: var(--label-bg);
  color: var(--label-text);
  padding: 0.5rem 1rem;
  border-radius: 0.25rem;
  z-index: 10;
}

#nerve-label {
  top: 3.5rem;
  }
  
#nerve-label.hidden {
  display: none;
  }

#nerve-segments {
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem;
  justify-content: center;
  }
  
.nerve-segment {
  padding: 0.25rem 0.5rem;
  background: var(--button-bg);
  color: var(--button-text);
  border-radius: 0.25rem;
  font-size: 0.95rem;
  cursor: pointer;
  user-select: none;
  }
  
.nerve-segment:active {
  background: var(--bg-toggle);
  color: #000;
  }

#object-label.paused, #serial-label.paused {
  opacity: 0.5;
  font-style: italic;
  background-color: var(--label-disabled);
  }

/* serial status */
#serial-label {
  position: absolute;
  top: 1rem;
  left: 1rem;
  background-color: var(--label-bg);
  color: var(--label-text);
  padding: 0.5rem 1rem;
  border-radius: 0.25rem;
  z-index: 10;
}

/* Hamburger toggle */
#hamburger {
  position: absolute;
  top: 1rem;
  right: calc(env(safe-area-inset-right, 1rem) + 1rem);
  z-index: 20;
  font-size: 1.5rem;
  background: none;
  border: none;
  color: var(--ham-color);
  padding: 0;
  width: auto;
  box-sizing: content-box
}

#hamburger:hover, #expertMenuButton:hover {
  opacity: var(--ham-hover);
}

/* Main content area */
.content {
  flex: 1;
  display: flex;
  position: relative;
  overflow: hidden;
}

.viewerContainer {
  flex: 1;
  position: relative;
  container-type: inline-size;
  pointer-events: auto;
  overflow: hidden;
  background-color: var(--viewer-bg);
  container-type: "inline-size";
  container-name: "viewerContainer";
}

/* Full-size canvas */
.viewerContainer canvas {
  position: absolute;
  top: 0; left: 0;
  width: 100%;
  height: 100%;
  display: block;
  object-fit: contain;
  background-color: var(--viewer-bg);
}

.bottom-bar, .side-panel {
  display: flex;
  background-color: var(--panel-bg);
  position: fixed;
}

.bottom-bar {
  left: 0;
  right: 0;
  bottom: 0;
  height: calc(var(--bottom-bar-h) + env(safe-area-inset-bottom));
  padding-bottom: env(safe-area-inset-bottom);
  background-color: var(--panel-bg);
  justify-content: space-around;
  z-index: 10;
  }

.bottom-bar {
  padding:
   0.5rem
   env(safe-area-inset-right)
   0.1rem
   env(safe-area-inset-left);
}
  
#expertToggle {
  width: 100%;
  /*margin: 0.5rem 0;*/
  cursor: pointer;
  }

#expertSection {
  display: flex;
  flex-direction: column;
  width: 100%;
  box-sizing: border-box;
  padding: 0.5rem 0;
  }
  
#expertSection button {
  width: 100%;
  text-align: center;
  box-sizing: border-box;
  margin: 0.5rem 0;
  }

#expertSection input[type="range"] {
  margin-bottom: 0.5rem;
  }

#expertSection label {
  font-family: Arial;
  font-size: 0.875rem;
  margin-bottom: 0.25rem;
  margin-top: 0.25rem;
  display: block;
  }
  
/* Side panel (off-canvas) */
.side-panel {
  flex-direction: column;
  align-items: center;
  width: 10rem;
  height: 100vh;
  height: 100dvh;
  max-height: 100vh;
  left: env(safe-area-inset-left, 0);
  padding-top: 0;
  padding: 1rem;
  transform: translateX(-150%);
  transition: transform 0.3s ease;
  overflow-y: scroll; /* auto */
  overflow-x: hidden;
  overscroll-behavior: conains;
  -webkit-overflow-scrolling: touch;
  touch-action: pan-y;
  padding-bottom: 0.25rem;
  z-index: 30;
}

.side-panel > :first-child {
  margin-top: 0;
  }
  
.side-panel.open {
  transform: translateX(0);
  }

#expertToggleContainer {
  display: inline-flex;
  justify-content: center;
  align-items: center;
  gap: 0.25rem;
  padding: 0;
  margin: 0.15rem 0;
  width: auto;
  }

#expertToggleContainer label {
  margin-top: 0;
  padding-top: 0;
  }
  
#expertToggleContainer input[type="checkbox"] {
  margin: 0:
  }
  
.viewer-logo {
  position: absolute;
  width: 3rem;
  aspect-ratio: 1;
  opacity: 0.08;
  pointer-events: none;
  z-index: 10;
  background:  url('/images/logo_light.png') no-repeat center / contain;
  transform: translateY(-1.5rem);
  bottom: 2rem;
}

.viewer-logo-right {
  right: 1rem;
  }

.viewer-logo-left {
  left: 1rem;
}

body.dark-mode .viewer-logo {
    background-image: url('/images/logo_dark.png');
    opacity: 0.15;
  }
  
/* base button */
button {
  display: inline-block;
  padding: 0.75rem 1rem;
  font-size: clamp(0.875rem, 1.5vw, 1.125rem);
  background-color: var(--button-bg);
  color: var(--button-text);
  border: none;
  border-radius: 0;
  transition: background-color 0.1s ease;
  box-sizing: border-box;
  }
  
button:hover:not(:disabled) {
  background-color: var(--button-hover);
}

button:disabled {
  background-color: var(--button-disabled); 
  opacity: 0.5;
  pointer-events: none;
}

button:active {
  background-color: var(--bg-toggle);
  color: #000;
  outline: 2px solid var(--outline-toggle);
  outline-offset: 2px;
  box-shadow: 0 0 5px rgba(160,160,160,0.6);
  transition: background-color 0.25s ease, box-shadow 0.25s ease;  
}

button.toggle-active {
  background-color: var(--bg-toggle) !important;
  color: #000;
  outline: 2px solid var(--outline-toggle);
  outline-offset: 2px;
  box-shadow: 0 0 5px rgba(160,160,160,0.6);
}

.bottom-bar button {
  flex: 1;
  margin: 0 0.25rem;
  padding: 0.5rem;
  max-height: 2.5rem;
  border-radius: 0;
}

.side-panel button {
  width: 100%;
  margin: 0.5rem 0;
}

/* Portrait: enforce 16:9 viewer */
@media (orientation: portrait) {
  .viewerContainer {
    width: 100%;
    aspect-ratio: 16 / 9;
    max-height: calc(100vh - 4rem - env(safe-area-inset-bottom));
    margin: 0 auto;
  }
  .bottom-bar {
  bottom: env(safe-area-inset-bottom, 0.0rem);
  height: calc(var(--bottom-bar-h) + 0.5rem);
  }
  .viewerContainer {
  max-height: calc(100vh - var(--bottom-bar-h) - 1.0rem - env(safe-area-inset-top));
  }
  
  .bottom-bar button {
    flex: 1;
    margin: 0 0.25rem;
    paddin: 0.75rem 1rem;
    max-height: 3.5rem;
    font-size: clamp(0.875rem, 1.5vw, 1.25rem);
    border-radius: 0;
    }
  }