:root{--bg: #f5f6f8;--surface: #ffffff;--border: #e3e5ea;--text: #1c1f24;--text-muted: #5b6370;--accent: #2563eb;--accent-soft: #eaf0ff;--radius: 10px;--shadow: 0 1px 2px rgba(15, 23, 42, .04), 0 4px 16px rgba(15, 23, 42, .06);--font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif}*{box-sizing:border-box}html,body{margin:0;padding:0}body{font-family:var(--font-sans);color:var(--text);background:var(--bg);line-height:1.5;min-height:100vh;display:flex;flex-direction:column}.container{width:100%;max-width:720px;margin:0 auto;padding:0 20px}.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.is-hidden{display:none!important}.site-header{background:var(--surface);border-bottom:1px solid var(--border);padding:16px 0}.site-brand{font-weight:700;font-size:1.1rem;color:var(--text);text-decoration:none;letter-spacing:-.01em}main{flex:1;padding:40px 20px 60px}.intro h1{font-size:clamp(1.6rem,4vw,2.2rem);margin:0 0 8px;letter-spacing:-.02em}.intro p{color:var(--text-muted);margin:0 0 32px}.calculator{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow);overflow:hidden}.calc-card{padding:22px 24px}.calc-card+.calc-card{border-top:1px solid var(--border)}.calc-card-title{font-size:.8rem;text-transform:uppercase;letter-spacing:.06em;color:var(--text-muted);font-weight:600;margin:0 0 14px}.calc-row{display:flex;flex-wrap:wrap;align-items:center;gap:10px;font-size:1.1rem}.calc-label{color:var(--text-muted);white-space:nowrap}.calc-field{position:relative;display:inline-flex;align-items:center}.calc-field input{width:110px;padding:10px 12px;font:inherit;font-size:1.1rem;color:var(--text);background:var(--surface);border:1px solid var(--border);border-radius:8px;transition:border-color .15s,box-shadow .15s}.calc-field input:focus{outline:none;border-color:var(--accent);box-shadow:0 0 0 3px var(--accent-soft)}.calc-field input::placeholder{color:#b0b6bf}.calc-field input::-webkit-outer-spin-button,.calc-field input::-webkit-inner-spin-button{-webkit-appearance:none;margin:0}.calc-field input[type=number]{-moz-appearance:textfield}.calc-suffix{position:absolute;right:12px;color:var(--text-muted);pointer-events:none;font-size:1rem}.calc-field:has(.calc-suffix) input{padding-right:28px}.calc-result{display:block;margin-top:14px;font-size:1.6rem;font-weight:700;letter-spacing:-.02em;color:#c7cdd6;word-break:break-all;transition:color .15s}.calc-result.is-ready{color:var(--accent)}.content-section{margin-top:56px}.content-section h2{font-size:1.35rem;letter-spacing:-.01em;margin:0 0 18px}.content-section h3{font-size:1.02rem;margin:24px 0 6px}.content-section p{color:var(--text-muted);margin:0 0 10px}.content-section strong{color:var(--text)}.formula{display:inline-block;font-family:ui-monospace,SF Mono,Menlo,Consolas,monospace;background:var(--accent-soft);color:var(--accent);padding:2px 8px;border-radius:6px;font-size:.92rem;margin-left:4px}.faq-item{border-top:1px solid var(--border);padding:14px 0}.faq-item:last-of-type{border-bottom:1px solid var(--border)}.faq-item summary{cursor:pointer;font-weight:600;color:var(--text);list-style:none;position:relative;padding-right:24px}.faq-item summary::-webkit-details-marker{display:none}.faq-item summary:after{content:"+";position:absolute;right:0;top:50%;transform:translateY(-50%);font-size:1.2rem;color:var(--text-muted);transition:transform .15s}.faq-item[open] summary:after{content:"−"}.faq-item p{margin:10px 0 0}.site-footer{border-top:1px solid var(--border);background:var(--surface);padding:20px 0;text-align:center;color:var(--text-muted);font-size:.9rem}.site-footer p{margin:0}@media(max-width:480px){.mode-tab{font-size:.82rem;padding:12px 6px}.calc-row{font-size:1rem}.calc-field input{width:90px;font-size:1rem}}