:root{--primary:#1a5276;--primary-light:#2980b9;--primary-dark:#0d3b5e;--accent:#2ecc71;--accent-warm:#e67e22;--highlight:#e74c3c;--bg:#f5f6fa;--bg-card:#fff;--text:#2c3e50;--text-light:#7f8c8d;--text-heading:#1a252f;--border:#dcdde1;--shadow:0 2px 12px #00000014;--shadow-hover:0 6px 24px #00000024;--radius:12px;--radius-sm:8px;--sans:"Segoe UI", system-ui, -apple-system, sans-serif;--heading:"Segoe UI", system-ui, -apple-system, sans-serif;--mono:"Consolas", "Monaco", ui-monospace, monospace;font:16px/1.6 var(--sans);color:var(--text);background:var(--bg);-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}*,:before,:after{box-sizing:border-box;margin:0;padding:0}body{min-height:100vh}#root{flex-direction:column;min-height:100vh;display:flex}a{color:var(--primary-light);text-decoration:none}a:hover{text-decoration:underline}img{max-width:100%;display:block}h1,h2,h3,h4{font-family:var(--heading);color:var(--text-heading);font-weight:600}.container{max-width:1200px;margin:0 auto;padding:0 24px}.header{border-bottom:1px solid var(--border);z-index:100;background:#fff;padding:16px 24px;position:sticky;top:0;box-shadow:0 1px 4px #0000000a}.header-inner{justify-content:space-between;align-items:center;max-width:1200px;margin:0 auto;display:flex}.header-logo{color:var(--primary);align-items:center;gap:8px;font-size:1.4rem;font-weight:700;display:flex}.header-logo:hover{text-decoration:none}.header-logo .logo-icon{font-size:1.6rem}.header-right{align-items:center;gap:16px;display:flex}.header-back{color:var(--text-light);font-size:.9rem;transition:color .2s}.header-back:hover{color:var(--primary);text-decoration:none}.lang-switch{border:1px solid var(--border);border-radius:20px;font-size:.85rem;display:flex;overflow:hidden}.lang-switch button{cursor:pointer;color:var(--text-light);background:0 0;border:none;padding:6px 14px;transition:all .2s}.lang-switch button.active{background:var(--primary);color:#fff}.lang-switch button:hover:not(.active){background:var(--bg)}.main{flex:1}.hero-section{text-align:center;color:#fff;background:linear-gradient(135deg,#1a5276 0%,#2980b9 50%,#1a5276 100%);padding:60px 24px 40px}.hero-section h1{color:#fff;letter-spacing:2px;margin-bottom:8px;font-size:3rem}.hero-section .hero-sub{opacity:.85;max-width:600px;margin:0 auto;font-size:1.1rem}.section-title{text-align:center;color:var(--primary-dark);margin:48px 0 24px;font-size:1.8rem;position:relative}.section-title:after{content:"";background:var(--accent);border-radius:2px;width:60px;height:3px;margin:8px auto 0;display:block}.section-desc{text-align:center;color:var(--text-light);max-width:600px;margin-bottom:32px;margin-left:auto;margin-right:auto}.reference-section{max-width:1200px;margin:0 auto;padding:0 24px 16px}.reference-card{background:var(--bg-card);border-radius:var(--radius);box-shadow:var(--shadow);border-left:4px solid var(--accent-warm);align-items:flex-start;gap:24px;padding:24px;display:flex}.reference-card img{border-radius:var(--radius-sm);flex-shrink:0;max-width:300px}.reference-info h3{color:var(--accent-warm);margin-bottom:8px;font-size:1.2rem}.reference-info p{color:var(--text-light);font-size:.9rem;line-height:1.8}.elements-grid{grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:24px;max-width:1200px;margin:0 auto;padding:0 24px 60px;display:grid}.element-card{background:var(--bg-card);border-radius:var(--radius);box-shadow:var(--shadow);cursor:pointer;flex-direction:column;transition:transform .25s,box-shadow .25s;display:flex;overflow:hidden}.element-card:hover{box-shadow:var(--shadow-hover);transform:translateY(-4px)}.element-card .card-img{aspect-ratio:2/3;background:linear-gradient(135deg,#e8f0fe 0%,#d4e6f1 100%);justify-content:center;align-items:center;display:flex;position:relative;overflow:hidden}.element-card .card-img .placeholder-icon{opacity:.6;font-size:5rem}.element-card .card-img .atomic-number{color:var(--primary);opacity:.25;font-size:2rem;font-weight:800;position:absolute;top:12px;right:16px}.element-card .card-body{flex-direction:column;flex:1;padding:18px 20px 20px;display:flex}.element-card .card-body h3{color:var(--text-heading);margin-bottom:4px;font-size:1.3rem}.element-card .card-body .card-en{color:var(--text-light);margin-bottom:10px;font-size:.85rem}.element-card .card-body .card-desc{color:var(--text);flex:1;font-size:.9rem;line-height:1.5}.detail-page{flex-direction:column;min-height:100vh;display:flex}.detail-content{flex:1;gap:32px;width:100%;max-width:1200px;margin:0 auto;padding:24px;display:flex}.model-viewer-panel{background:var(--bg-card);border-radius:var(--radius);min-width:0;box-shadow:var(--shadow);flex-direction:column;flex:1;display:flex;overflow:hidden}.model-viewer-panel .viewer-header{border-bottom:1px solid var(--border);color:var(--text-light);justify-content:space-between;align-items:center;padding:12px 20px;font-size:.9rem;display:flex}.model-viewer-panel canvas{flex:1;display:block}.info-panel{flex-shrink:0;width:380px;max-height:calc(100vh - 80px);position:sticky;top:80px;overflow-y:auto}.info-panel .info-card{background:var(--bg-card);border-radius:var(--radius);box-shadow:var(--shadow);margin-bottom:16px;padding:24px}.info-panel .info-card h3{color:var(--primary);border-bottom:2px solid var(--bg);margin-bottom:12px;padding-bottom:8px;font-size:1.1rem}.info-panel .element-name-zh{color:var(--text-heading);font-size:2rem;font-weight:700}.info-panel .element-name-en{color:var(--text-light);margin-bottom:16px;font-size:1.1rem}.info-panel .info-row{border-bottom:1px dotted var(--border);justify-content:space-between;padding:6px 0;font-size:.9rem;display:flex}.info-panel .info-row .label{color:var(--text-light)}.info-panel .info-row .value{color:var(--text-heading);font-weight:500}.info-panel .info-text{color:var(--text);font-size:.9rem;line-height:1.7}.footer{background:var(--primary-dark);color:#fff9;text-align:center;margin-top:auto;padding:20px;font-size:.85rem}@media (width<=768px){.detail-content{flex-direction:column}.info-panel{width:100%;max-height:none;position:static}.model-viewer-panel{min-height:350px}.reference-card{flex-direction:column}.hero-section h1{font-size:2rem}}.model-placeholder{height:100%;min-height:400px;color:var(--text-light);text-align:center;flex-direction:column;justify-content:center;align-items:center;padding:40px;display:flex}.model-placeholder .placeholder-icon{margin-bottom:16px;font-size:4rem}.model-placeholder p{font-size:.9rem}