:root{--bg: #f8fafc;--surface: #ffffff;--border: #e2e8f0;--text: #0f172a;--text-muted: #64748b;--text-tag: #475569;--tag-bg: #e2e8f0;--neutral-bg: #f1f5f9;--accent: #3b82f6;--insight-bg: #eff6ff;--insight-text: #1e40af;--insight-border: #3b82f6;--error-bg: #fef2f2;--error-text: #b91c1c}[data-theme=dark]{--bg: #0f172a;--surface: #1e293b;--border: #334155;--text: #f1f5f9;--text-muted: #94a3b8;--text-tag: #94a3b8;--tag-bg: #334155;--neutral-bg: #0f172a;--accent: #60a5fa;--insight-bg: #1e3a5f;--insight-text: #93c5fd;--insight-border: #60a5fa;--error-bg: #450a0a;--error-text: #fca5a5}*,*:before,*:after{box-sizing:border-box;margin:0;padding:0}.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}input,button{font-family:inherit}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif;background:var(--bg);color:var(--text);min-height:100vh;padding:24px 16px}main{max-width:480px;margin:0 auto}header{display:flex;justify-content:space-between;align-items:flex-start;margin-bottom:32px}.header-left{flex:1}.brand{display:flex;align-items:center;gap:8px}.brand-icon{font-size:1.6rem;line-height:1}h1{font-size:2rem;font-weight:800;line-height:1.1;letter-spacing:-.02em}.brand-accent{color:var(--accent)}.subtitle{color:var(--text-muted);font-size:.875rem;margin-top:6px}.feature-tags{display:flex;flex-wrap:wrap;gap:6px;margin-top:10px}.tag{background:var(--tag-bg);color:var(--text-tag);border-radius:20px;padding:2px 10px;font-size:.75rem;font-weight:500;letter-spacing:.01em}.tag--link{display:inline-block;margin-top:6px;background:var(--insight-bg);color:var(--accent);border:1px solid color-mix(in srgb,var(--accent) 30%,transparent);text-decoration:none;cursor:pointer}.tag--link:hover{background:color-mix(in srgb,var(--accent) 15%,transparent)}.theme-toggle{background:var(--neutral-bg);border:1px solid var(--border);border-radius:20px;padding:7px 13px;font-size:.8125rem;font-weight:500;color:var(--text);display:flex;align-items:center;gap:5px;cursor:pointer;transition:background .15s;white-space:nowrap;margin-left:12px;flex-shrink:0;margin-top:4px}.theme-toggle:hover{background:var(--border)}.theme-toggle:focus-visible{outline:2px solid var(--accent);outline-offset:2px}.mode-toggle{display:flex;background:var(--neutral-bg);border-radius:20px;padding:3px;margin-bottom:20px}.mode-btn{flex:1;padding:8px 12px;border:none;border-radius:16px;font-size:.8125rem;font-weight:500;color:var(--text-muted);background:transparent;cursor:pointer;text-decoration:none;transition:all .15s}.mode-btn.active{background:var(--surface);color:var(--text);font-weight:600;box-shadow:0 1px 3px #00000026}[data-theme=dark] .mode-btn.active{box-shadow:0 1px 4px #00000080}form{background:var(--surface);border-radius:12px;padding:24px;border:1px solid var(--border);margin-bottom:24px}.field{margin-bottom:16px}label{display:block;font-size:.75rem;font-weight:500;color:var(--text-muted);margin-bottom:6px}input{width:100%;padding:10px 14px;font-size:1rem;border:1.5px solid var(--border);border-radius:8px;background:var(--surface);color:var(--text);transition:border-color .15s;-webkit-appearance:none;-moz-appearance:none;appearance:none}input[type=number]::-webkit-outer-spin-button,input[type=number]::-webkit-inner-spin-button{-webkit-appearance:none}input[type=number]{-moz-appearance:textfield}input:focus{border-color:var(--accent)}input:focus:not(:focus-visible){outline:none}input:focus-visible{outline:2px solid var(--accent);outline-offset:2px}.time-wrapper{position:relative}.time-wrapper input{padding-right:28px;border-radius:8px}.time-arrows{position:absolute;right:0;top:0;bottom:0;width:26px;display:flex;flex-direction:column;border-left:1.5px solid var(--border)}.time-arrow-btn{flex:1;background:var(--bg);border:none;cursor:pointer;display:flex;align-items:center;justify-content:center;font-size:.5rem;color:var(--text-muted);padding:0;line-height:1;transition:background .1s}.time-arrow-btn:first-child{border-radius:0 6px 0 0;border-bottom:1px solid var(--border)}.time-arrow-btn:last-child{border-radius:0 0 6px}.time-arrow-btn:hover{background:var(--border);color:var(--text)}.time-wrapper:focus-within .time-arrows{border-left-color:var(--accent)}button[type=submit]{width:100%;padding:12px;background:var(--text);color:var(--surface);font-size:.875rem;font-weight:600;border:none;border-radius:8px;cursor:pointer;margin-top:8px;transition:background .15s}button[type=submit]:hover{background:var(--text-tag)}button[type=submit]:focus-visible{outline:2px solid var(--accent);outline-offset:2px}#results,#treadmill-results{background:var(--surface);border-radius:12px;padding:24px;border:1px solid var(--border)}#treadmill-results .pace-hero{margin-bottom:0}.pace-hero{text-align:center;margin-bottom:24px}.label{display:block;font-size:.6875rem;font-weight:400;text-transform:uppercase;letter-spacing:.08em;color:var(--text-muted);margin-top:0;margin-bottom:4px}.pace-value{display:block;font-size:3rem;font-weight:800;line-height:1;color:var(--text)}.pace-unit{font-size:.875rem;color:var(--text-muted)}.prediction-grid{display:grid;grid-template-columns:1fr 1fr;gap:12px;background:var(--neutral-bg);border-radius:8px;padding:16px;margin-bottom:16px}.prediction{text-align:center}.race-label{display:block;font-size:.6875rem;text-transform:uppercase;letter-spacing:.08em;color:var(--text-muted);margin-bottom:2px}output{display:block;font-size:.9375rem;font-weight:600;color:var(--text)}.insight{background:var(--insight-bg);border-left:3px solid var(--insight-border);padding:10px 14px;border-radius:4px;color:var(--insight-text);font-size:.8125rem;line-height:1.5}.error{color:var(--error-text);font-size:.875rem;padding:10px 14px;background:var(--error-bg);border-radius:8px;margin-top:8px}.error:empty{padding:0;margin:0;background:transparent}.label-row{display:flex;justify-content:space-between;align-items:center;margin-bottom:6px}.label-row label{margin-bottom:0}.unit-toggle{display:flex;background:var(--neutral-bg);border-radius:12px;padding:2px}.unit-btn{padding:3px 10px;border:none;border-radius:10px;font-size:.6875rem;font-weight:500;color:var(--text-muted);background:transparent;cursor:pointer;transition:all .15s}.unit-btn.active{background:var(--surface);color:var(--text);font-weight:600;box-shadow:0 1px 2px #0000001a}.unit-btn:focus-visible{outline:2px solid var(--accent);outline-offset:2px}.section-heading{font-size:1rem;font-weight:600;color:var(--text-muted);margin-bottom:12px;letter-spacing:-.01em}.seo-content{margin-top:40px;padding-top:32px;border-top:1px solid var(--border);color:var(--text)}.seo-content h2{font-size:1.125rem;font-weight:700;margin-bottom:16px;margin-top:32px;color:var(--text)}.seo-content h2:first-child{margin-top:0}.seo-grid{display:grid;grid-template-columns:1fr;gap:16px;margin-bottom:32px}.seo-card{background:var(--surface);border:1px solid var(--border);border-radius:10px;padding:16px 20px}.seo-card h3{font-size:.875rem;font-weight:600;margin-bottom:6px;color:var(--text)}.seo-card p{font-size:.8125rem;color:var(--text-muted);line-height:1.6}.faq-list{display:flex;flex-direction:column}.faq-list dt{background:var(--surface);border:1px solid var(--border);border-radius:10px 10px 0 0;border-bottom:none;padding:16px 20px 6px;font-size:.875rem;font-weight:600;color:var(--text);margin-top:16px}.faq-list dt:first-child{margin-top:0}.faq-list dd{background:var(--surface);border:1px solid var(--border);border-top:none;border-radius:0 0 10px 10px;font-size:.8125rem;color:var(--text-muted);line-height:1.6;margin:0;padding:0 20px 16px}footer{max-width:480px;margin:40px auto 0;padding:24px 16px 32px;border-top:1px solid var(--border)}footer p{font-size:.75rem;color:var(--text-muted);text-align:center;line-height:1.6}footer a{color:var(--accent);text-decoration:none}footer a:hover{text-decoration:underline}.back-link{display:inline-flex;align-items:center;gap:6px;font-size:.8125rem;color:var(--accent);text-decoration:none;font-weight:500;margin-bottom:20px}.back-link:hover{text-decoration:underline}.page-title{font-size:1.125rem;font-weight:700;letter-spacing:-.01em;margin-bottom:6px}.page-desc{font-size:.8125rem;color:var(--text-muted);margin-bottom:20px;line-height:1.5}.gender-toggle{display:flex;background:var(--neutral-bg);border-radius:20px;padding:3px;width:fit-content;margin-bottom:16px}section+section{margin-top:16px}.stats-table-wrap{background:var(--surface);border:1px solid var(--border);border-radius:10px;overflow:hidden;margin-top:6px}.stats-table{width:100%;border-collapse:collapse}.stats-table th{padding:8px 10px;font-size:.6875rem;font-weight:500;color:var(--text-muted);background:var(--bg);border-bottom:1px solid var(--border);text-align:center}.stats-table th:first-child{text-align:left}.stats-table td{padding:9px 10px;font-size:.8125rem;border-bottom:1px solid var(--neutral-bg);text-align:center}.stats-table td:first-child{text-align:left;font-weight:600}.stats-table tr:last-child td{border-bottom:none}.stats-table tr:nth-child(2n) td{background:color-mix(in srgb,var(--neutral-bg) 60%,transparent)}.level-badge{display:inline-block;padding:2px 7px;border-radius:4px;font-size:.6875rem;font-weight:500}.level-beginner{background:#fef3c7;color:#92400e}.level-intermediate{background:#dbeafe;color:#1d4ed8}.level-advanced{background:#dcfce7;color:#15803d}[data-theme=dark] .level-beginner{background:#451a03;color:#fcd34d}[data-theme=dark] .level-intermediate{background:#1e3a5f;color:#93c5fd}[data-theme=dark] .level-advanced{background:#052e16;color:#86efac}.td-beginner{color:#92400e}.td-intermediate{color:#1d4ed8;font-weight:500}.td-advanced{color:#15803d;font-weight:600}[data-theme=dark] .td-beginner{color:#fcd34d}[data-theme=dark] .td-intermediate{color:#93c5fd}[data-theme=dark] .td-advanced{color:#86efac}.sources{margin-top:32px;padding-top:20px;border-top:1px solid var(--border)}.sources-heading{font-size:.6875rem;font-weight:600;text-transform:uppercase;letter-spacing:.08em;color:var(--text-muted);margin-bottom:10px}.sources-list{list-style:none;display:flex;flex-direction:column;gap:6px}.sources-list li{font-size:.75rem;color:var(--text-muted);display:flex;gap:6px;align-items:baseline}.sources-list li:before{content:"↗";color:var(--accent);flex-shrink:0}.sources-list a{color:var(--accent);text-decoration:none}.sources-list a:hover{text-decoration:underline}