/* ============================
   3D EduTech — Premium Design System
   Dark-first Glassmorphism + Cyber Teal
   ============================ */

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

:root{
  --bg-primary:#06080d;
  --bg-secondary:#0d1117;
  --bg-tertiary:#161b22;
  --bg-card:rgba(255,255,255,0.03);
  --bg-glass:rgba(13,17,23,0.75);
  --accent:#00d4aa;
  --accent-hover:#00eabc;
  --accent-glow:rgba(0,212,170,0.25);
  --accent-subtle:rgba(0,212,170,0.08);
  --gradient:linear-gradient(135deg,#00d4aa,#667eea);
  --gradient-warm:linear-gradient(135deg,#667eea,#764ba2);
  --text-primary:#e8edf5;
  --text-secondary:#7a8599;
  --border-color:rgba(255,255,255,0.06);
  --border-hover:rgba(0,212,170,0.3);
  --shadow-sm:0 2px 8px rgba(0,0,0,0.3);
  --shadow-md:0 8px 24px rgba(0,0,0,0.4);
  --shadow-glow:0 0 24px var(--accent-glow);
  --radius-sm:0.5rem;
  --radius-md:0.75rem;
  --radius-lg:1rem;
  --radius-xl:1.5rem;
  --transition:all 0.25s cubic-bezier(0.4,0,0.2,1);
}

[data-theme="light"]{
  --bg-primary:#f4f6f9;
  --bg-secondary:#ffffff;
  --bg-tertiary:#edf0f5;
  --bg-card:rgba(0,0,0,0.02);
  --bg-glass:rgba(255,255,255,0.8);
  --accent:#0099cc;
  --accent-hover:#00aadd;
  --accent-glow:rgba(0,153,204,0.2);
  --accent-subtle:rgba(0,153,204,0.07);
  --text-primary:#1a1d23;
  --text-secondary:#6b7280;
  --border-color:rgba(0,0,0,0.07);
  --border-hover:rgba(0,153,204,0.3);
  --shadow-sm:0 2px 8px rgba(0,0,0,0.06);
  --shadow-md:0 8px 24px rgba(0,0,0,0.1);
}

html{scroll-behavior:smooth}

body{
  font-family:'Inter',-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
  background:var(--bg-primary);
  color:var(--text-primary);
  line-height:1.6;
  overflow-x:hidden;
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
}

.container{max-width:1280px;margin:0 auto;padding:0 2rem}

/* === UTILITIES === */
.glass{
  background:var(--bg-glass);
  backdrop-filter:blur(20px);
  -webkit-backdrop-filter:blur(20px);
  border:1px solid var(--border-color);
}
.gradient-text{
  background:var(--gradient);
  -webkit-background-clip:text;
  -webkit-text-fill-color:transparent;
  background-clip:text;
}
.glow{box-shadow:var(--shadow-glow)}

/* === HEADER === */
.header{
  position:fixed;top:0;left:0;right:0;z-index:1000;
  background:var(--bg-glass);
  backdrop-filter:blur(20px);
  -webkit-backdrop-filter:blur(20px);
  border-bottom:1px solid var(--border-color);
  padding:0 2rem;
}
.header::after{
  content:'';position:absolute;bottom:0;left:0;width:100%;height:1px;
  background:var(--gradient);opacity:0.35;
}
.header-content{
  display:flex;align-items:center;justify-content:space-between;
  max-width:1280px;margin:0 auto;padding:0.875rem 0;
}
.logo{display:flex;align-items:center;gap:0.625rem;text-decoration:none;color:inherit}
.logo-icon{font-size:1.5rem}
.logo-text{font-size:1.25rem;font-weight:700;letter-spacing:-0.02em}
.nav{display:flex;gap:2rem;align-items:center}
.nav-link{
  color:var(--text-secondary);text-decoration:none;font-weight:500;
  font-size:0.9375rem;transition:var(--transition);position:relative;padding:0.25rem 0;
}
.nav-link::after{
  content:'';position:absolute;bottom:-2px;left:0;width:0;height:2px;
  background:var(--accent);border-radius:1px;transition:width 0.3s ease;
}
.nav-link:hover,.nav-link.active{color:var(--accent)}
.nav-link:hover::after,.nav-link.active::after{width:100%}

/* Theme Toggle */
.theme-toggle{
  background:var(--bg-tertiary);border:1px solid var(--border-color);
  border-radius:var(--radius-lg);padding:0.5rem 0.75rem;cursor:pointer;
  transition:var(--transition);display:flex;align-items:center;gap:0.375rem;
  color:var(--text-secondary);font-size:0.9375rem;font-family:inherit;
}
.theme-toggle:hover{border-color:var(--accent);color:var(--accent);box-shadow:var(--shadow-glow)}
.theme-icon{font-size:1.125rem}

/* === 3D VIEWER PAGE === */
.viewer-container{
  display:flex;height:calc(100vh - 56px);margin-top:56px;
  background:var(--bg-primary);
}

/* Sidebar */
.viewer-sidebar{
  width:300px;background:var(--bg-secondary);
  border-right:1px solid var(--border-color);
  display:flex;flex-direction:column;overflow:hidden;flex-shrink:0;
}
.sidebar-header{
  padding:1.25rem 1.25rem 1rem;border-bottom:1px solid var(--border-color);
}
.sidebar-title{
  font-size:1rem;font-weight:600;color:var(--text-primary);
  margin-bottom:0.125rem;letter-spacing:-0.01em;
}
.sidebar-subtitle{font-size:0.75rem;color:var(--text-secondary)}

.components-list{flex:1;overflow-y:auto;padding:0.625rem}
.components-list::-webkit-scrollbar{width:3px}
.components-list::-webkit-scrollbar-track{background:transparent}
.components-list::-webkit-scrollbar-thumb{background:var(--border-color);border-radius:2px}
.components-list::-webkit-scrollbar-thumb:hover{background:var(--accent)}

.component-item{
  padding:0.75rem 0.875rem;background:transparent;
  border:1px solid transparent;border-left:3px solid transparent;
  border-radius:var(--radius-md);margin-bottom:0.375rem;cursor:pointer;
  transition:var(--transition);
}
.component-item:hover{
  background:var(--accent-subtle);border-left-color:var(--accent);
  border-color:var(--border-hover);transform:translateX(3px);
}
.component-item.active{
  background:var(--accent-subtle);border-left-color:var(--accent);
  border-color:var(--border-hover);
}
.component-name{font-weight:600;font-size:0.875rem;margin-bottom:0.1rem}
.component-category{
  font-size:0.6875rem;color:var(--text-secondary);
  text-transform:uppercase;letter-spacing:0.04em;
}
.component-item.active .component-name{color:var(--accent)}

/* Viewer Main */
.viewer-main{flex:1;display:flex;flex-direction:column;position:relative}
.viewer-canvas{
  flex:1;position:relative;
  background:radial-gradient(ellipse at 40% 40%,#0f1923 0%,#06080d 100%);
}
#canvas-container{width:100%;height:100%}

/* Viewer Controls */
.viewer-controls{
  position:absolute;bottom:1.5rem;left:1.5rem;
  display:flex;gap:0.5rem;z-index:10;
}
.control-btn{
  padding:0.5rem 0.875rem;
  background:rgba(6,8,13,0.8);
  backdrop-filter:blur(12px);
  border:1px solid var(--border-color);
  border-radius:var(--radius-md);
  color:var(--text-primary);
  font-size:0.8rem;cursor:pointer;
  transition:var(--transition);
  display:flex;align-items:center;gap:0.375rem;
  font-weight:500;font-family:inherit;
}
.control-btn:hover{border-color:var(--accent);box-shadow:var(--shadow-glow);color:var(--accent)}

/* Controls Hint */
.controls-hint{
  position:absolute;top:1.25rem;right:1.25rem;
  background:rgba(6,8,13,0.75);backdrop-filter:blur(12px);
  padding:0.75rem 1rem;border-radius:var(--radius-md);
  border:1px solid var(--border-color);
  font-size:0.75rem;color:var(--text-secondary);
}
.controls-hint p{margin:0.2rem 0}
.controls-hint strong{color:var(--text-primary)}

/* Info Panel Bottom */
.viewer-info{
  padding:1rem 1.25rem;background:var(--bg-secondary);
  border-top:1px solid var(--border-color);max-height:200px;overflow-y:auto;
}
.info-title{font-size:1.125rem;font-weight:600;margin-bottom:0.375rem}
.info-description{
  color:var(--text-secondary);line-height:1.6;
  margin-bottom:0.75rem;font-size:0.9rem;
}
.info-specs{
  display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:0.375rem;
}
.spec-item{
  padding:0.375rem 0.625rem;background:var(--bg-card);
  border:1px solid var(--border-color);border-left:2px solid var(--accent);
  border-radius:var(--radius-sm);font-size:0.8rem;color:var(--text-secondary);
}
.loading-message{text-align:center;padding:2rem;color:var(--text-secondary)}

/* === SCENE.JS SIDEBAR (components-menu) === */
.main-container{display:flex;height:calc(100vh - 56px);gap:0;padding:0;margin-top:56px}
.scene-container{
  flex:1;position:relative;
  background:radial-gradient(ellipse at 40% 40%,#0f1923 0%,#06080d 100%);
  overflow:hidden;margin-left:300px;transition:margin-left 0.3s;
}
#canvas-container{width:100%;height:100%;position:relative}

.components-menu{
  position:absolute;top:0;left:0;bottom:0;width:300px;
  background:var(--bg-secondary);border-right:1px solid var(--border-color);
  padding:1.5rem 0;z-index:100;display:flex;flex-direction:column;
  overflow:hidden;animation:slideIn 0.35s cubic-bezier(0.4,0,0.2,1);
}
@keyframes slideIn{from{opacity:0;transform:translateX(-16px)}to{opacity:1;transform:translateX(0)}}

.components-menu h3{
  color:var(--text-primary);font-size:1rem;font-weight:600;
  margin:0 1.25rem 1rem;padding-bottom:0.875rem;
  border-bottom:1px solid var(--border-color);
  display:flex;align-items:center;gap:0.5rem;letter-spacing:-0.01em;
}
.menu-buttons{
  display:flex;flex-direction:column;gap:0.25rem;
  overflow-y:auto;padding:0 0.625rem;flex:1;
}
.menu-buttons::-webkit-scrollbar{width:3px}
.menu-buttons::-webkit-scrollbar-track{background:transparent}
.menu-buttons::-webkit-scrollbar-thumb{background:var(--border-color);border-radius:2px}
.menu-buttons::-webkit-scrollbar-thumb:hover{background:var(--accent)}

.menu-button{
  background:transparent;color:var(--text-primary);
  border:1px solid transparent;border-left:3px solid transparent;
  border-radius:var(--radius-md);padding:0.7rem 0.875rem;cursor:pointer;
  font-size:0.875rem;font-weight:500;transition:var(--transition);
  display:flex;align-items:center;gap:0.625rem;position:relative;font-family:inherit;
}
.menu-button::before{
  content:attr(data-icon);font-size:1.125rem;width:2rem;height:2rem;
  display:flex;align-items:center;justify-content:center;
  background:var(--bg-tertiary);border-radius:var(--radius-sm);
  flex-shrink:0;transition:var(--transition);
}
.menu-button:hover{
  background:var(--accent-subtle);border-left-color:var(--accent);
  border-color:var(--border-hover);transform:translateX(3px);
}
.menu-button:hover::before{background:var(--accent);color:#000}
.menu-button.active{
  background:var(--accent-subtle);border-left-color:var(--accent);border-color:var(--border-hover);
}
.menu-button.active::before{background:var(--accent);color:#000}
.menu-button .button-name{
  flex:1;text-align:left;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;
}
.menu-loading{
  color:var(--text-secondary);font-size:0.8125rem;
  text-align:center;padding:1rem;animation:pulse 1.5s ease-in-out infinite;
}

/* === INFO PANEL (left side, scene_standalone) === */
.info-panel{
  min-width:340px;max-width:55vw;flex-basis:360px;flex-shrink:0;
  background:var(--bg-secondary);border-right:1px solid var(--border-color);
  padding:1.75rem;display:flex;flex-direction:column;overflow-y:auto;
  position:relative;order:-1;
}
.info-panel::-webkit-scrollbar{width:3px}
.info-panel::-webkit-scrollbar-track{background:transparent}
.info-panel::-webkit-scrollbar-thumb{background:var(--accent);border-radius:2px}

.info-content{animation:fadeUp 0.35s cubic-bezier(0.4,0,0.2,1)}
@keyframes fadeUp{from{opacity:0;transform:translateY(12px)}to{opacity:1;transform:translateY(0)}}

.welcome-message h2{
  font-size:1.25rem;font-weight:600;margin-bottom:0.875rem;letter-spacing:-0.02em;
}
.welcome-message p{color:var(--text-secondary);line-height:1.6;margin-bottom:1.25rem;font-size:0.9375rem}

.component-info h2{font-size:1.5rem;font-weight:700;margin-bottom:0.5rem;letter-spacing:-0.02em}
.component-info .component-type{
  display:inline-block;background:var(--gradient);color:#000;
  padding:0.3rem 0.75rem;border-radius:2rem;
  font-size:0.6875rem;font-weight:700;margin-bottom:1.125rem;
  text-transform:uppercase;letter-spacing:0.05em;
}
.component-info p{color:var(--text-secondary);line-height:1.7;margin-bottom:0.875rem;font-size:0.9rem}
.component-info .specs{
  background:var(--bg-card);padding:1.25rem;border-radius:var(--radius-lg);
  margin-top:1.25rem;border:1px solid var(--border-color);
}
.component-info .specs h3{
  color:var(--accent);margin-bottom:0.875rem;font-size:0.75rem;
  font-weight:700;text-transform:uppercase;letter-spacing:0.06em;
}
.component-info .specs ul{list-style:none}
.component-info .specs li{
  padding:0.5rem 0;color:var(--text-secondary);
  border-bottom:1px solid var(--border-color);font-size:0.875rem;
  padding-left:1rem;position:relative;
}
.component-info .specs li:last-child{border-bottom:none}
.component-info .specs li::before{
  content:'';position:absolute;left:0;top:50%;transform:translateY(-50%);
  width:4px;height:4px;background:var(--accent);border-radius:50%;
}

/* Resize Handle */
.resize-handle{
  position:absolute;right:-6px;top:0;bottom:0;width:12px;
  cursor:col-resize;z-index:100;
}
.resize-handle:hover,.resize-handle.active{background:var(--accent-subtle)}
.resize-handle:hover::after,.resize-handle.active::after{
  content:'';position:absolute;width:2px;height:100%;
  left:5px;background:var(--accent);box-shadow:0 0 6px var(--accent);opacity:0.5;
}

/* === LOADER === */
.loader-overlay{
  position:absolute;inset:0;display:flex;flex-direction:column;
  align-items:center;justify-content:center;gap:1rem;
  background:rgba(6,8,13,0.88);backdrop-filter:blur(16px);
  z-index:200;pointer-events:none;opacity:0;transition:opacity 0.3s;
}
.loader-overlay[style*="display: flex"]{opacity:1}
.loader-content{display:flex;flex-direction:column;align-items:center;gap:1rem}
.loader-icon{
  width:52px;height:52px;position:relative;
  display:flex;align-items:center;justify-content:center;
}
.loader-icon::before{
  content:'';position:absolute;inset:0;border-radius:50%;
  border:2px solid var(--border-color);border-top-color:var(--accent);border-right-color:var(--accent);
  animation:spin 0.8s linear infinite;
}
.loader-icon svg{width:24px;height:24px;fill:var(--text-primary)}
.loader-progress-bar{
  width:160px;height:2px;background:rgba(255,255,255,0.06);border-radius:1px;overflow:hidden;
}
.loader-progress-fill{
  height:100%;background:var(--gradient);border-radius:1px;transition:width 0.3s;
}
.loader-percent,.loader-copy{
  font-size:0.75rem;color:var(--accent);font-weight:600;
  text-transform:uppercase;letter-spacing:0.06em;
}

/* === TOASTS === */
.toast-container{
  position:fixed;bottom:1.5rem;right:1.5rem;
  display:flex;flex-direction:column;gap:0.5rem;z-index:1000;
}
.toast{
  background:var(--bg-glass);backdrop-filter:blur(16px);
  border-left:3px solid var(--accent);color:var(--text-primary);
  padding:0.875rem 1.125rem;border-radius:var(--radius-md);
  box-shadow:var(--shadow-md);min-width:260px;
  display:flex;align-items:center;justify-content:space-between;
  font-size:0.875rem;border:1px solid var(--border-color);
  animation:slideInToast 0.3s cubic-bezier(0.4,0,0.2,1);
  transition:all 0.3s;
}
.toast.error{border-left-color:#ef4444}
.toast.warning{border-left-color:#f59e0b}
.toast.success{border-left-color:#10b981}
.toast.hiding{opacity:0;transform:translateX(100%)}
.toast-close{
  background:none;border:none;color:var(--text-secondary);
  cursor:pointer;font-size:1.125rem;padding:0 0.25rem;font-family:inherit;
}
.toast-close:hover{color:var(--text-primary)}

/* === LESSON MODE === */
.lesson-start-container{
  padding:1rem 1.75rem;border-top:1px solid var(--border-color);
  background:var(--bg-secondary);
}
.lesson-start-btn{
  width:100%;background:var(--gradient);color:#000;font-weight:700;
  padding:0.75rem;border-radius:var(--radius-md);border:none;cursor:pointer;
  font-size:0.9rem;display:flex;align-items:center;justify-content:center;
  gap:0.5rem;transition:var(--transition);text-transform:uppercase;
  letter-spacing:0.04em;font-family:inherit;
}
.lesson-start-btn:hover{transform:translateY(-2px);box-shadow:var(--shadow-glow)}

.lesson-controls{
  margin-top:1rem;padding:1rem;background:var(--bg-card);
  border-radius:var(--radius-lg);border:1px solid var(--accent);
  display:flex;flex-wrap:wrap;gap:0.5rem;align-items:center;
  box-shadow:0 0 16px var(--accent-glow);
}
.lesson-progress{
  display:flex;justify-content:space-between;align-items:center;
  color:var(--accent);font-size:0.75rem;font-weight:600;
  text-transform:uppercase;letter-spacing:0.06em;width:100%;
}
.progress-bar{height:2px;background:rgba(255,255,255,0.06);border-radius:1px;overflow:hidden;width:100%}
.progress-fill{height:100%;background:var(--accent);width:0;transition:width 0.3s}
.lesson-buttons{display:flex;gap:0.5rem;width:100%}
.lesson-btn,.lesson-nav-btn{
  flex:1;padding:0.625rem;background:transparent;border:1px solid var(--border-color);
  color:var(--text-primary);border-radius:var(--radius-sm);cursor:pointer;
  font-weight:500;transition:var(--transition);display:flex;align-items:center;
  justify-content:center;gap:0.375rem;font-family:inherit;font-size:0.875rem;
}
.lesson-btn:hover,.lesson-nav-btn:hover{
  background:rgba(255,255,255,0.04);border-color:var(--text-secondary);
}
.lesson-btn.primary,.lesson-nav-btn.primary{
  background:var(--accent);border-color:var(--accent);color:#000;font-weight:700;
}
.lesson-btn.primary:hover,.lesson-nav-btn.primary:hover{
  background:var(--accent-hover);box-shadow:var(--shadow-glow);
}
.lesson-btn.danger,.lesson-nav-btn.danger{
  border-color:rgba(239,68,68,0.3);color:#ef4444;
}
.lesson-btn.danger:hover,.lesson-nav-btn.danger:hover{background:rgba(239,68,68,0.06)}
.lesson-nav-btn{flex:none}
.lesson-nav-btn.danger{width:100%;margin-top:0.25rem}
#lesson-step-counter{font-family:'JetBrains Mono',monospace;color:var(--accent);font-weight:700}
.component-info.lesson-active{border:1px solid var(--accent);box-shadow:0 0 16px var(--accent-glow)}

/* === COMPONENTS INFO LIST === */
#components-info-list{list-style:none;display:flex;flex-direction:column;gap:0.5rem;margin-top:1rem}
#components-info-list li{
  background:var(--bg-card);color:var(--text-secondary);padding:0.75rem 1rem;
  border-radius:var(--radius-md);border-left:3px solid var(--accent);
  cursor:pointer;font-size:0.875rem;transition:var(--transition);
}
#components-info-list li:hover{
  background:var(--accent-subtle);color:var(--text-primary);transform:translateX(3px);
}

/* === ANIMATIONS === */
@keyframes spin{to{transform:rotate(360deg)}}
@keyframes pulse{0%,100%{opacity:0.5}50%{opacity:1}}
@keyframes fadeIn{from{opacity:0;transform:translateY(12px)}to{opacity:1;transform:translateY(0)}}
@keyframes slideInToast{from{opacity:0;transform:translateY(12px)}to{opacity:1;transform:translateY(0)}}

/* === SCROLLBAR === */
::-webkit-scrollbar{width:4px}
::-webkit-scrollbar-track{background:transparent}
::-webkit-scrollbar-thumb{background:var(--border-color);border-radius:2px}
::-webkit-scrollbar-thumb:hover{background:var(--accent)}

/* === TYPOGRAPHY === */
h1,h2,h3,h4{text-rendering:optimizeLegibility;letter-spacing:-0.01em}
a,button{transition:var(--transition)}

/* === RESPONSIVE === */
@media(max-width:1024px){
  .viewer-container{flex-direction:column}
  .viewer-sidebar{width:100%;height:160px}
  .components-list{display:flex;overflow-x:auto;overflow-y:hidden;padding:0.625rem}
  .component-item{min-width:160px;margin-right:0.375rem;margin-bottom:0}
  .info-panel{min-width:100%;max-width:100%;border-right:none;border-top:1px solid var(--border-color)}
  .scene-container{margin-left:0}
  .components-menu{width:100%;position:static;border:none;border-top:1px solid var(--border-color)}
}
@media(max-width:768px){
  .nav{display:none}
  .controls-hint{display:none}
  .container{padding:0 1rem}
  .menu-buttons{
    display:grid;grid-template-columns:repeat(auto-fit,minmax(90px,1fr));gap:0.375rem;
  }
  .menu-button{padding:0.5rem;font-size:0.75rem;justify-content:center}
  .menu-button .button-name{display:none}
  .toast-container{bottom:1rem;right:1rem}
  .toast{min-width:220px}
}