*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
:root{--primary:#0066ff;--primary-dark:#0052cc;--primary-light:#e6f0ff;--secondary:#00c853;--warning:#ff9100;--danger:#ff3d00;--text:#1a1a2e;--text-light:#64748b;--bg:#f8fafc;--white:#ffffff;--border:#e2e8f0;--shadow:0 4px 20px rgba(0,0,0,0.08);--shadow-lg:0 10px 40px rgba(0,0,0,0.12);--radius:16px;--radius-sm:8px;--transition:all 0.3s cubic-bezier(0.4,0,0.2,1)}
html{scroll-behavior:smooth;font-size:16px}
body{font-family:'Noto Sans SC',system-ui,-apple-system,sans-serif;background:var(--bg);color:var(--text);line-height:1.8;min-height:100vh;overflow-x:hidden}
.bg-decoration{position:fixed;top:0;left:0;width:100%;height:100%;pointer-events:none;z-index:-1;background:linear-gradient(135deg,#667eea 0%,#764ba2 50%,#f093fb 100%);opacity:0.03}
header{position:fixed;top:0;left:0;right:0;z-index:1000;background:rgba(255,255,255,0.95);backdrop-filter:blur(20px);border-bottom:1px solid var(--border)}
nav{max-width:1200px;margin:0 auto;padding:1rem 2rem;display:flex;justify-content:space-between;align-items:center}
.logo{display:flex;align-items:center;text-decoration:none}
.logo img{height:40px;width:auto}
.nav-links{display:flex;gap:2rem;list-style:none}
.nav-links a{text-decoration:none;color:var(--text-light);font-weight:500;transition:var(--transition);position:relative}
.nav-links a:hover{color:var(--primary)}
.nav-links a::after{content:'';position:absolute;bottom:-4px;left:0;width:0;height:2px;background:var(--primary);transition:var(--transition)}
.nav-links a:hover::after{width:100%}
main{padding-top:70px}
.hero{background:linear-gradient(135deg,#667eea 0%,#764ba2 100%);color:var(--white);padding:3rem 2rem;text-align:center}
.hero-content{max-width:800px;margin:0 auto}
h1{font-size:clamp(1.5rem,4vw,2.25rem);font-weight:700;margin-bottom:0.75rem}
.subtitle{font-size:1.1rem;opacity:0.9}
.calculator-section{padding:3rem 2rem;margin-top:-2rem;position:relative;z-index:10}
.calculator-container{max-width:1000px;margin:0 auto;display:grid;grid-template-columns:1fr 1fr;gap:2rem}
.calculator-card,.result-card{background:var(--white);border-radius:var(--radius);box-shadow:var(--shadow-lg);overflow:hidden}
.card-header,.result-header{padding:1.5rem 2rem;background:linear-gradient(135deg,#667eea 0%,#764ba2 100%);color:var(--white)}
.card-header h2,.result-header h3{font-size:1.35rem;margin-bottom:0.25rem}
.card-header p{opacity:0.9;font-size:0.95rem}
.bmi-form{padding:2rem}
.input-group{margin-bottom:1.5rem}
.input-group label{display:block;font-weight:600;margin-bottom:0.5rem;color:var(--text)}
.input-wrapper{position:relative;display:flex;align-items:center}
.input-wrapper input{width:100%;padding:1rem 1.25rem;padding-right:4rem;border:2px solid var(--border);border-radius:var(--radius-sm);font-size:1rem;transition:var(--transition);font-family:inherit}
.input-wrapper input:focus{outline:none;border-color:var(--primary);box-shadow:0 0 0 4px var(--primary-light)}
.input-wrapper .unit{position:absolute;right:1rem;color:var(--text-light);font-size:0.9rem;font-weight:600;pointer-events:none}
.input-help{display:block;margin-top:0.5rem;font-size:0.85rem;color:var(--text-light)}
.btn-calculate{width:100%;padding:1rem;background:linear-gradient(135deg,#667eea 0%,#764ba2 100%);color:var(--white);border:none;border-radius:var(--radius-sm);font-size:1.1rem;font-weight:600;cursor:pointer;transition:var(--transition);display:flex;align-items:center;justify-content:center;gap:0.5rem;font-family:inherit}
.btn-calculate:hover{transform:translateY(-2px);box-shadow:0 10px 30px rgba(102,126,234,0.4)}
.btn-calculate:active{transform:translateY(0)}
.result-content{padding:2rem}
.bmi-display{text-align:center;margin-bottom:1.5rem}
.bmi-number{font-size:3.5rem;font-weight:700;background:linear-gradient(135deg,#667eea 0%,#764ba2 100%);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text;line-height:1}
.bmi-label{color:var(--text-light);margin-top:0.5rem}
.bmi-status{text-align:center;margin-bottom:1.5rem}
.status-text{display:inline-block;padding:0.5rem 1.5rem;border-radius:2rem;font-weight:600;font-size:1rem;background:var(--bg);color:var(--text-light)}
.status-text.thin{background:#e3f2fd;color:#1565c0}
.status-text.normal{background:#e8f5e9;color:#2e7d32}
.status-text.overweight{background:#fff3e0;color:#ef6c00}
.status-text.obese{background:#ffebee;color:#c62828}
.bmi-gauge{margin:1.5rem 0}
.gauge-track{position:relative;height:12px;background:linear-gradient(to right,#64b5f6 0%,#81c784 25%,#81c784 45%,#ffb74d 60%,#e57373 100%);border-radius:6px;overflow:visible}
.gauge-fill{height:100%;border-radius:6px}
.gauge-pointer{position:absolute;top:50%;width:20px;height:20px;background:var(--white);border:3px solid var(--text);border-radius:50%;transform:translate(-50%,-50%);transition:left 0.5s ease;left:0}
.gauge-labels{display:flex;justify-content:space-between;margin-top:0.75rem;font-size:0.8rem;color:var(--text-light)}
.health-tips{margin-top:1.5rem;padding:1.25rem;background:var(--bg);border-radius:var(--radius-sm);border-left:4px solid var(--primary)}
.health-tips h4{font-size:1rem;margin-bottom:0.5rem;color:var(--primary)}
.health-tips p{font-size:0.95rem;color:var(--text-light);line-height:1.6}
.container{max-width:1200px;margin:0 auto;padding:0 2rem}
.info-section{padding:4rem 0;background:var(--white)}
.info-section h2,.formula-section h2,.features-section h2,.faq-section h2,.knowledge-section h2,.related-section h2{text-align:center;font-size:1.75rem;margin-bottom:0.5rem;color:var(--text)}
.section-desc{text-align:center;color:var(--text-light);margin-bottom:2rem}
.table-wrapper{overflow-x:auto}
.bmi-table{width:100%;border-collapse:collapse;background:var(--white);border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow)}
.bmi-table caption{padding:1rem;font-weight:600;text-align:left;background:var(--bg)}
.bmi-table th,.bmi-table td{padding:1.25rem 1.5rem;text-align:left;border-bottom:1px solid var(--border)}
.bmi-table th{background:linear-gradient(135deg,#667eea 0%,#764ba2 100%);color:var(--white);font-weight:600}
.bmi-table tbody tr:hover{background:var(--bg)}
.table-note{margin-top:1.5rem;padding:1rem;background:var(--bg);border-radius:var(--radius-sm);font-size:0.9rem;color:var(--text-light)}
.level-badge{display:inline-block;padding:0.35rem 1rem;border-radius:2rem;font-weight:600;font-size:0.9rem}
.level-badge.thin{background:#e3f2fd;color:#1565c0}
.level-badge.normal{background:#e8f5e9;color:#2e7d32}
.level-badge.overweight{background:#fff3e0;color:#ef6c00}
.level-badge.obese{background:#ffebee;color:#c62828}
.formula-section{padding:4rem 0;background:var(--bg)}
.formula-card{max-width:800px;margin:2rem auto 0;background:var(--white);border-radius:var(--radius);padding:2.5rem;box-shadow:var(--shadow)}
.formula-display{text-align:center;padding:2rem;background:linear-gradient(135deg,#667eea 0%,#764ba2 100%);border-radius:var(--radius-sm);margin-bottom:2rem}
.formula-text{font-size:1.5rem;font-weight:700;color:var(--white)}
.formula-detail{margin-bottom:2rem}
.formula-detail h4{margin-bottom:1rem;color:var(--text)}
.formula-detail ul{list-style:none;padding-left:0}
.formula-detail li{padding:0.5rem 0;color:var(--text-light);border-bottom:1px dashed var(--border)}
.formula-example h4{margin-bottom:1rem;color:var(--text)}
.formula-example p{color:var(--text-light);margin-bottom:0.5rem}
.example-steps{background:var(--bg);padding:1.5rem;border-radius:var(--radius-sm);margin:1rem 0}
.step{display:flex;align-items:center;gap:1rem;padding:0.75rem 0;border-bottom:1px solid var(--border)}
.step:last-child{border-bottom:none}
.step-num{width:28px;height:28px;background:linear-gradient(135deg,#667eea 0%,#764ba2 100%);color:white;border-radius:50%;display:flex;align-items:center;justify-content:center;font-weight:600;font-size:0.9rem;flex-shrink:0}
.example-result{color:var(--secondary);font-weight:600;margin-top:1rem;padding:1rem;background:#e8f5e9;border-radius:var(--radius-sm)}
.features-section{padding:4rem 0;background:var(--white)}
.features-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:1.5rem;margin-top:2rem}
.feature-card{background:var(--bg);padding:2rem;border-radius:var(--radius);text-align:center;transition:var(--transition)}
.feature-card:hover{transform:translateY(-5px);box-shadow:var(--shadow)}
.feature-icon{font-size:2.5rem;margin-bottom:1rem}
.feature-card h3{font-size:1.15rem;margin-bottom:0.75rem;color:var(--text)}
.feature-card p{color:var(--text-light);font-size:0.95rem;line-height:1.6}
.knowledge-section{padding:4rem 0;background:var(--bg)}
.knowledge-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(350px,1fr));gap:1.5rem;margin-top:2rem}
.knowledge-card{background:var(--white);padding:2rem;border-radius:var(--radius);border-top:4px solid;border-image:linear-gradient(135deg,#667eea,#764ba2) 1}
.knowledge-card h3{font-size:1.15rem;margin-bottom:1rem;color:var(--text)}
.knowledge-card p{color:var(--text-light);line-height:1.8;font-size:0.95rem}
.faq-section{padding:4rem 0;background:var(--white)}
.faq-list{max-width:900px;margin:2rem auto 0}
.faq-item{background:var(--bg);border-radius:var(--radius-sm);margin-bottom:1rem;overflow:hidden}
.faq-item summary{padding:1.25rem 1.5rem;cursor:pointer;display:flex;justify-content:space-between;align-items:center;font-weight:600;list-style:none;transition:var(--transition)}
.faq-item summary:hover{background:var(--white)}
.faq-item summary::-webkit-details-marker{display:none}
.faq-question{flex:1;font-size:1rem}
.faq-icon{width:24px;height:24px;position:relative;flex-shrink:0}
.faq-icon::before,.faq-icon::after{content:'';position:absolute;background:var(--text);transition:var(--transition)}
.faq-icon::before{width:14px;height:2px;top:11px;left:5px}
.faq-icon::after{width:2px;height:14px;top:5px;left:11px}
.faq-item[open] .faq-icon::after{transform:rotate(90deg);opacity:0}
.faq-answer{padding:0 1.5rem 1.5rem;color:var(--text-light);line-height:1.8}
.faq-answer p{font-size:0.95rem}
.related-section{padding:4rem 0;background:var(--bg)}
.related-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(250px,1fr));gap:1.5rem;margin-top:2rem}
.related-card{background:var(--white);padding:1.5rem;border-radius:var(--radius);box-shadow:var(--shadow)}
.related-card h3{font-size:1.1rem;margin-bottom:0.75rem;color:var(--primary)}
.related-card p{color:var(--text-light);font-size:0.9rem;line-height:1.6}
footer{background:linear-gradient(135deg,#1a1a2e 0%,#16213e 100%);color:var(--white);padding:3rem 2rem 1.5rem}
.footer-content{max-width:1200px;margin:0 auto}
.footer-main{display:grid;grid-template-columns:2fr 1fr 1fr;gap:3rem;margin-bottom:2rem;padding-bottom:2rem;border-bottom:1px solid rgba(255,255,255,0.1)}
.footer-brand .site-name{font-size:1.25rem;font-weight:700;margin-bottom:0.5rem}
.footer-brand .site-desc{color:rgba(255,255,255,0.7);font-size:0.9rem;line-height:1.6}
.footer-nav h4{font-size:1rem;margin-bottom:1rem;color:var(--white)}
.footer-nav ul{list-style:none}
.footer-nav li{margin-bottom:0.5rem}
.footer-nav a{color:rgba(255,255,255,0.7);text-decoration:none;font-size:0.9rem;transition:var(--transition)}
.footer-nav a:hover{color:var(--white)}
.footer-bottom{display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:1rem}
.footer-bottom .copyright{color:rgba(255,255,255,0.7);font-size:0.85rem}
.footer-bottom .icp a{color:rgba(255,255,255,0.7);text-decoration:none;font-size:0.85rem;transition:var(--transition)}
.footer-bottom .icp a:hover{color:var(--white)}
@media(max-width:900px){.calculator-container{grid-template-columns:1fr}.footer-main{grid-template-columns:1fr 1fr}}
@media(max-width:768px){nav{padding:0.75rem 1rem}.nav-links{gap:1rem;font-size:0.9rem}.hero{padding:2rem 1rem}h1{font-size:1.4rem}.subtitle{font-size:0.95rem}.bmi-form{padding:1.5rem}.result-content{padding:1.5rem}.bmi-number{font-size:3rem}.container{padding:0 1rem}.features-grid,.knowledge-grid{grid-template-columns:1fr}.footer-main{grid-template-columns:1fr;gap:2rem}.footer-bottom{flex-direction:column;text-align:center}}
@media(max-width:480px){.nav-links{display:none}.calculator-section{padding:2rem 1rem}.input-wrapper input{padding:0.875rem 1rem;padding-right:3.5rem;font-size:0.95rem}.formula-text{font-size:1.1rem}}
.section-image{max-width:800px;margin:2rem auto 0;text-align:center}
.section-image img{width:100%;height:auto;border-radius:var(--radius);box-shadow:var(--shadow)}
.input-wrapper input.error{border-color:var(--danger);animation:shake 0.5s ease}
@keyframes shake{0%,100%{transform:translateX(0)}25%{transform:translateX(-5px)}75%{transform:translateX(5px)}}
@keyframes fadeInUp{from{opacity:0;transform:translateY(20px)}to{opacity:1;transform:translateY(0)}}
.calculator-card,.result-card{animation:fadeInUp 0.6s ease forwards}
.result-card{animation-delay:0.2s}