:root{--primary-color:#4361ee;--secondary-color:#3a0ca3;--accent-color:#7209b7;--light-color:#f8f9fa;--dark-color:#212529;--gray-color:#6c757d;--success-color:#4cc9f0;--warning-color:#f72585;--temp-primary:#ef4444;--temp-cold:#3b82f6;--temp-hot:#f97316;--temp-gradient:linear-gradient(135deg,#3b82f6 0%,#ef4444 100%);--border-radius:12px;--box-shadow:0 8px 24px rgba(0,0,0,0.1);--transition:all 0.3s ease}*{margin:0;padding:0;box-sizing:border-box;font-family:'Segoe UI','Microsoft YaHei',sans-serif}body{background-color:#f0f2f5;color:var(--dark-color);line-height:1.6}.container{width:100%;max-width:1200px;margin:0 auto;padding:0 20px}header{background:linear-gradient(135deg,var(--primary-color),var(--secondary-color));color:white;padding:20px 0;box-shadow:0 4px 12px rgba(0,0,0,0.1);position:sticky;top:0;z-index:100}.header-content{display:flex;justify-content:space-between;align-items:center}.logo{display:flex;align-items:center;gap:15px}.logo i{font-size:2.5rem}.logo h1{font-size:1.8rem;font-weight:700}.logo span{color:var(--success-color)}nav ul{display:flex;list-style:none;gap:25px}nav a{color:white;text-decoration:none;font-weight:600;font-size:1.1rem;padding:8px 12px;border-radius:6px;transition:var(--transition)}nav a:hover,nav a.active{background-color:rgba(255,255,255,0.2)}main{padding:40px 0}.section-title{font-size:1.8rem;margin-bottom:25px;color:var(--secondary-color);display:flex;align-items:center;gap:10px}.section-title i{color:var(--accent-color)}.tools-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:25px;margin-bottom:40px}.tool-card{background:white;border-radius:var(--border-radius);padding:25px;box-shadow:var(--box-shadow);transition:var(--transition);cursor:pointer;border:2px solid transparent}.tool-card:hover{transform:translateY(-5px);border-color:var(--primary-color)}.tool-card i{font-size:2.5rem;color:var(--primary-color);margin-bottom:15px}.tool-card h3{font-size:1.4rem;margin-bottom:10px;color:var(--dark-color)}.tool-card p{color:var(--gray-color);margin-bottom:20px}.use-tool-btn{background-color:var(--primary-color);color:white;border:none;padding:10px 20px;border-radius:6px;font-weight:600;cursor:pointer;transition:var(--transition);width:100%}.use-tool-btn:hover{background-color:var(--secondary-color)}.tool-detail{background:white;border-radius:var(--border-radius);padding:30px;box-shadow:var(--box-shadow);margin-top:30px;display:none}.tool-detail.active{display:block}.tool-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:25px;padding-bottom:15px;border-bottom:2px solid #f0f2f5}.tool-header h2{font-size:1.6rem;color:var(--secondary-color)}.close-tool{background:none;border:none;font-size:1.5rem;color:var(--gray-color);cursor:pointer;transition:var(--transition)}.close-tool:hover{color:var(--warning-color)}.temp-wrapper{max-width:1000px;margin:0 auto}.converter-deck{display:grid;grid-template-columns:repeat(auto-fit,minmax(300px,1fr));gap:30px;margin-bottom:30px}.temp-card{background:#f8f9fa;border:1px solid #e9ecef;border-radius:16px;padding:30px 20px;text-align:center;transition:var(--transition);position:relative;overflow:hidden}.temp-card::before{content:'';position:absolute;top:0;left:0;width:100%;height:6px}.temp-card.celsius::before{background:var(--temp-cold)}.temp-card.fahrenheit::before{background:var(--temp-hot)}.temp-card.kelvin::before{background:var(--accent-color)}.temp-card:hover{box-shadow:0 10px 20px rgba(0,0,0,0.08);transform:translateY(-5px);border-color:#cbd5e1}.card-icon{font-size:3rem;margin-bottom:20px;opacity:0.8}.celsius .card-icon{color:var(--temp-cold)}.fahrenheit .card-icon{color:var(--temp-hot)}.kelvin .card-icon{color:var(--accent-color)}.unit-label{font-size:1.2rem;font-weight:700;margin-bottom:15px;color:var(--gray-color)}.temp-input{width:100%;border:none;background:transparent;text-align:center;font-size:3.5rem;font-weight:700;font-family:'Consolas',monospace;color:var(--dark-color);outline:none;padding:10px 0;border-radius:8px;transition:var(--transition)}.temp-input:focus{background:white;box-shadow:0 4px 12px rgba(0,0,0,0.05)}.unit-symbol{font-size:1.2rem;color:var(--gray-color);font-weight:600;margin-top:5px;display:block}.copy-row{margin-top:20px;display:flex;justify-content:center;gap:10px}.btn-sm{padding:8px 15px;background:white;border:1px solid #e0e0e0;border-radius:6px;cursor:pointer;font-size:0.9rem;transition:var(--transition);display:inline-flex;align-items:center;gap:5px}.btn-sm:hover{background:#f1f5f9;border-color:var(--primary-color);color:var(--primary-color)}.info-bar{background:#eff6ff;border-left:4px solid var(--primary-color);padding:15px 20px;border-radius:4px;font-size:0.95rem;color:#1e40af;display:flex;align-items:center;gap:10px;transition:all 0.2s ease}.copy-feedback{transition:all 0.2s}@media (max-width:768px){.temp-input{font-size:2.5rem}.converter-deck{grid-template-columns:1fr}}