*{margin:0;padding:0;box-sizing:border-box}:root{--primary-color: #4a90e2;--primary-hover: #357abd;--text-primary: #2c3e50;--text-secondary: #5a6c7d;--text-light: #8b9dc3;--bg-primary: #e6ebf0;--bg-secondary: #dce4ec;--shadow-light: #ffffff;--shadow-dark: #b8c5d1;--border-radius: 20px;--border-radius-small: 12px;--transition: all .3s ease}[data-theme=dark]{--primary-color: #5aa3f0;--primary-hover: #4a90e2;--text-primary: #e8eef5;--text-secondary: #b0bcc9;--text-light: #6b7d8f;--bg-primary: #2c3e50;--bg-secondary: #34495e;--shadow-light: #3a4d63;--shadow-dark: #1e2a3a}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,sans-serif;line-height:1.6;color:var(--text-primary);background:#000;transition:var(--transition);overflow:hidden}.navbar{position:fixed;top:0;width:100%;z-index:1000;padding:1rem 0}.nav-container{max-width:1200px;margin:0 auto;padding:0 2rem;display:flex;justify-content:space-between;align-items:center;background:var(--bg-primary);border-radius:var(--border-radius);padding:1rem 2rem}.nav-logo a{font-size:1.5rem;font-weight:700;color:var(--text-primary);text-decoration:none}.nav-menu{display:flex;gap:2rem;align-items:center}.nav-link{color:var(--text-secondary);text-decoration:none;font-weight:500;padding:.5rem 1rem;border-radius:var(--border-radius-small);transition:var(--transition)}.nav-link:hover,.nav-link.active{color:var(--primary-color);background:var(--bg-primary);box-shadow:inset 3px 3px 6px var(--shadow-dark),inset -3px -3px 6px var(--shadow-light)}.theme-toggle{background:var(--bg-primary);border:none;border-radius:50%;width:50px;height:50px;cursor:pointer;display:flex;align-items:center;justify-content:center;color:var(--text-primary);margin-left:1rem;transition:var(--transition);box-shadow:6px 6px 12px var(--shadow-dark),-6px -6px 12px var(--shadow-light)}.theme-toggle:hover{box-shadow:inset 3px 3px 6px var(--shadow-dark),inset -3px -3px 6px var(--shadow-light)}.theme-toggle:active{box-shadow:inset 6px 6px 12px var(--shadow-dark),inset -6px -6px 12px var(--shadow-light)}.theme-toggle svg{width:20px;height:20px}.theme-toggle .sun-icon{display:none}[data-theme=dark] .theme-toggle .sun-icon{display:block}[data-theme=dark] .theme-toggle .moon-icon{display:none}.nav-toggle{display:none;flex-direction:column;cursor:pointer;background:var(--bg-primary);border:none;border-radius:var(--border-radius-small);padding:.5rem;box-shadow:4px 4px 8px var(--shadow-dark),-4px -4px 8px var(--shadow-light)}.bar{width:24px;height:3px;background:var(--text-primary);margin:3px 0;border-radius:2px;transition:var(--transition)}.fullscreen-viewer{position:fixed;inset:0}.threejs-container{width:100%;height:100%}.placeholder-3d{display:flex;flex-direction:column;justify-content:center;align-items:center;height:100%;color:var(--text-light)}.placeholder-cube{width:120px;height:120px;background:var(--bg-primary);border-radius:var(--border-radius-small);margin-bottom:2rem;animation:float 4s ease-in-out infinite;box-shadow:12px 12px 24px var(--shadow-dark),-12px -12px 24px var(--shadow-light)}@keyframes float{0%,to{transform:translateY(0) rotateX(0) rotateY(0)}50%{transform:translateY(-20px) rotateX(15deg) rotateY(15deg)}}.viewer-info{position:absolute;bottom:2rem;left:2rem;background:#e6ebf0e6;-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);padding:1rem 2rem;border-radius:var(--border-radius);color:var(--text-secondary);font-size:.9rem;max-width:300px;z-index:100}[data-theme=dark] .viewer-info{background:#2c3e50e6}.performance-info,.controls-info,.loading-message,.error-message,#back-to-blackboard{display:none!important}@media (max-width: 768px){.navbar{top:1rem;left:1rem;right:1rem;transform:none;width:auto}.nav-container{padding:1rem}.nav-menu{position:fixed;left:-100%;top:100px;flex-direction:column;background:#e6ebf0f2;-webkit-backdrop-filter:blur(15px);backdrop-filter:blur(15px);width:calc(100% - 2rem);margin:0 1rem;text-align:center;transition:var(--transition);padding:2rem;border-radius:var(--border-radius);box-shadow:12px 12px 24px var(--shadow-dark),-12px -12px 24px var(--shadow-light)}[data-theme=dark] .nav-menu{background:#2c3e50f2}.nav-menu.active{left:0}.nav-toggle{display:flex}.viewer-info{left:1rem;bottom:1rem;max-width:calc(100% - 2rem);font-size:.8rem;padding:.8rem 1.5rem}}.paper-overlay{position:fixed;top:0;left:0;width:100%;height:100%;background:#000c;display:flex;justify-content:center;align-items:center;z-index:1000;opacity:0;visibility:hidden;transition:opacity .3s ease,visibility .3s ease;padding:20px;box-sizing:border-box}.paper-overlay.show{opacity:1;visibility:visible}.paper-modal{background:#fff;border-radius:8px;max-width:800px;max-height:90vh;width:100%;box-shadow:0 10px 30px #0000004d;overflow:hidden;transform:scale(.9);transition:transform .3s ease}.paper-overlay.show .paper-modal{transform:scale(1)}.paper-header{background:#f8f9fa;padding:20px;border-bottom:1px solid #e9ecef;display:flex;justify-content:space-between;align-items:center}.paper-header h1{margin:0;color:#333;font-size:1.5rem}.close-paper{background:none;border:none;font-size:2rem;cursor:pointer;color:#666;padding:0;width:30px;height:30px;display:flex;align-items:center;justify-content:center;border-radius:50%;transition:background-color .2s ease}.close-paper:hover{background-color:#e9ecef}.paper-content{padding:20px;max-height:calc(90vh - 100px);overflow-y:auto;color:#333;line-height:1.6}.paper-content h2{color:#2c3e50;margin-top:2rem;margin-bottom:1rem;font-size:1.3rem}.paper-content p{margin-bottom:1rem;text-align:justify}[data-theme=dark] .paper-modal{background:#2d3748;color:#e2e8f0}[data-theme=dark] .paper-header{background:#4a5568;border-bottom-color:#2d3748}[data-theme=dark] .paper-header h1,[data-theme=dark] .paper-content{color:#e2e8f0}[data-theme=dark] .paper-content h2{color:#63b3ed}[data-theme=dark] .close-paper{color:#a0aec0}[data-theme=dark] .close-paper:hover{background-color:#4a5568}@media (max-width: 768px){.paper-overlay{padding:10px}.paper-modal{max-height:95vh}.paper-header{padding:15px}.paper-header h1{font-size:1.2rem}.paper-content{padding:15px;max-height:calc(95vh - 80px)}}.nav-toggle.active .bar:nth-child(1){transform:rotate(45deg) translate(5px,5px)}.nav-toggle.active .bar:nth-child(2){opacity:0}.nav-toggle.active .bar:nth-child(3){transform:rotate(-45deg) translate(7px,-6px)}.mobile-menu-overlay{position:fixed;top:0;left:0;width:100%;height:100vh;background:#00000080;-webkit-backdrop-filter:blur(5px);backdrop-filter:blur(5px);z-index:999;opacity:0;visibility:hidden;transition:var(--transition)}.mobile-menu-overlay.active{opacity:1;visibility:visible}.mobile-menu{position:fixed;top:0;right:-100%;width:300px;height:100vh;background:var(--bg-primary);z-index:1000;transition:var(--transition);padding:2rem;box-shadow:-10px 0 30px var(--shadow-dark),10px 0 30px var(--shadow-light)}.mobile-menu.active{right:0}.mobile-menu-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:3rem;padding-top:1rem}.mobile-logo a{font-size:1.3rem;font-weight:700;color:var(--text-primary);text-decoration:none}.mobile-close{background:var(--bg-primary);border:none;border-radius:50%;width:40px;height:40px;cursor:pointer;display:flex;align-items:center;justify-content:center;color:var(--text-primary);transition:var(--transition);box-shadow:4px 4px 8px var(--shadow-dark),-4px -4px 8px var(--shadow-light)}.mobile-close:hover{box-shadow:inset 3px 3px 6px var(--shadow-dark),inset -3px -3px 6px var(--shadow-light)}.mobile-nav-links{display:flex;flex-direction:column;gap:1rem}.mobile-nav-link{color:var(--text-secondary);text-decoration:none;font-weight:500;padding:1rem 1.5rem;border-radius:var(--border-radius-small);transition:var(--transition);background:var(--bg-primary);box-shadow:6px 6px 12px var(--shadow-dark),-6px -6px 12px var(--shadow-light);text-align:center}.mobile-nav-link:hover,.mobile-nav-link.active{color:var(--primary-color);box-shadow:inset 4px 4px 8px var(--shadow-dark),inset -4px -4px 8px var(--shadow-light)}.mobile-theme-toggle{margin-top:2rem;display:flex;justify-content:center}.mobile-theme-toggle .theme-toggle{margin-left:0}@media (max-width: 768px){.nav-menu{display:none}.nav-toggle{display:flex}}@media (max-width: 480px){.mobile-menu{width:100%;right:-100%}}.loading-screen{position:fixed;top:0;left:0;width:100%;height:100vh;background:linear-gradient(135deg,#0f0f0f,#1a1a1a);display:flex;justify-content:center;align-items:center;z-index:10000;opacity:1;visibility:visible;transition:opacity .8s ease,visibility .8s ease}.loading-screen.hidden{opacity:0;visibility:hidden}.loading-container{text-align:center;max-width:500px;padding:2rem}.loading-logo{font-size:2.5rem;font-weight:700;color:#fff;margin-bottom:.5rem;letter-spacing:-.02em}.loading-title{font-size:1.2rem;color:#fffc;margin-bottom:3rem;font-weight:400}.progress-container{margin-bottom:3rem}.progress-bar{width:100%;height:4px;background:#ffffff1a;border-radius:2px;overflow:hidden;margin-bottom:1rem}.progress-fill{height:100%;background:linear-gradient(90deg,#4a90e2,#5aa3f0);border-radius:2px;width:0%;transition:width .3s ease}.progress-text{font-size:.9rem;color:#ffffffb3;font-weight:500}.loading-stages{display:flex;flex-direction:column;align-items:flex-start;gap:.8rem;margin-bottom:2rem;max-width:300px;margin-left:auto;margin-right:auto}.stage-item{display:flex;align-items:center;gap:1rem;color:#ffffff80;font-size:.9rem;transition:color .3s ease}.stage-item.active{color:#4a90e2}.stage-item.completed{color:#4ade80}.stage-dot{width:8px;height:8px;border-radius:50%;background:#fff3;transition:background .3s ease;flex-shrink:0}.stage-item.active .stage-dot{background:#4a90e2;animation:pulse 1.5s infinite}.stage-item.completed .stage-dot{background:#4ade80}@keyframes pulse{0%,to{opacity:1;transform:scale(1)}50%{opacity:.7;transform:scale(1.2)}}.loading-tip{font-size:.8rem;color:#fff6;margin-top:2rem;line-height:1.5}[data-theme=dark] .loading-screen{background:linear-gradient(135deg,#0f0f0f,#1a1a1a)}@media (max-width: 768px){.loading-container{padding:1.5rem}.loading-logo{font-size:2rem}.loading-title{font-size:1rem;margin-bottom:2rem}.loading-stages{max-width:250px}.stage-item{font-size:.8rem}}