*{box-sizing:border-box}
:root{--c:#3b5bdb;--bg:#f5f6fb;--ok:#2b8a3e;--err:#c92a2a;--warn:#e67700}
html{-webkit-text-size-adjust:100%}
body{margin:0;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,sans-serif;background:var(--bg);color:#212529;line-height:1.45;padding-bottom:env(safe-area-inset-bottom)}
.top{background:var(--c);color:#fff;padding:.7rem 1rem;padding-top:calc(.7rem + env(safe-area-inset-top))}
.top h1{margin:0;font-size:1.25rem}.top h1 span{font-weight:400;opacity:.8;font-size:.95rem}
.tabs{display:flex;overflow-x:auto;background:#fff;border-bottom:1px solid #dee2e6;position:sticky;top:0;z-index:5;-webkit-overflow-scrolling:touch}
.tabs button{flex:1 0 auto;border:0;background:none;padding:.75rem .8rem;font-size:.95rem;color:#495057;border-bottom:3px solid transparent}
.tabs button.active{color:var(--c);border-bottom-color:var(--c);font-weight:600}
main{max-width:780px;margin:0 auto;padding:.8rem}
.tab{display:none}.tab.active{display:block}
.card{background:#fff;border-radius:12px;padding:1rem;margin-bottom:.8rem;box-shadow:0 1px 3px rgba(0,0,0,.06)}
.lbl{display:block;font-weight:600;margin:.6rem 0 .25rem;font-size:.9rem}
input.math-input,textarea,select{width:100%;font-size:16px;padding:.6rem;border:1px solid #ced4da;border-radius:8px;font-family:ui-monospace,Menlo,monospace;background:#fff}
select{font-family:inherit}
textarea{resize:vertical}
.btn{display:inline-block;margin-top:.7rem;padding:.7rem 1rem;font-size:1rem;border-radius:8px;border:1px solid #ced4da;background:#fff;cursor:pointer}
.btn.primary{background:var(--c);color:#fff;border-color:var(--c)}
.btn:disabled{opacity:.5}
.row{display:flex;gap:.5rem;flex-wrap:wrap}
.preview{min-height:1.6rem;margin:.4rem 0;overflow-x:auto;color:#495057;font-size:.95rem}
.preview .err{color:var(--warn);font-size:.85rem}
.examples,.chips{display:flex;flex-wrap:wrap;gap:.4rem;margin-top:.3rem}
.chip{border:1px solid #c5d0f5;background:#eef2ff;color:#364fc7;border-radius:999px;padding:.35rem .7rem;font-size:.85rem;cursor:pointer}
.steps{list-style:none;padding:0;margin:0;counter-reset:s}
.steps li{border-left:3px solid #c5d0f5;padding:.4rem .7rem;margin:.6rem 0;counter-increment:s}
.steps .m{overflow-x:auto;overflow-y:hidden;padding:.2rem 0}
.steps .why{font-size:.9rem;color:#495057}
.steps .why:before{content:counter(s) ". ";font-weight:700;color:var(--c)}
.answer{background:#ebfbee;border:1px solid #b2f2bb;border-radius:10px;padding:.7rem;overflow-x:auto}
.errbox{background:#fff5f5;border:1px solid #ffc9c9;border-radius:10px;padding:.7rem;margin:.6rem 0}
.okbox{background:#ebfbee;border:1px solid #b2f2bb;border-radius:10px;padding:.7rem;margin:.6rem 0}
.lines{list-style:none;padding:0;margin:.4rem 0}
.lines li{display:flex;gap:.5rem;align-items:flex-start;padding:.35rem 0;border-bottom:1px dashed #e9ecef;overflow-x:auto}
.lines .st{flex:0 0 1.4rem;font-weight:700}
.lines .ok .st{color:var(--ok)}.lines .error .st{color:var(--err)}.lines .warn .st{color:var(--warn)}.lines .follows .st,.lines .unknown .st,.lines .unparsed .st,.lines .echo .st{color:#868e96}
.small{font-size:.82rem;color:#6c757d}
.note{background:#fff9db;border:1px solid #ffe066;border-radius:8px;padding:.6rem;font-size:.9rem}
.reason{font-size:.85rem;color:#5c7cfa;margin:.2rem 0 .5rem}
.bar{height:.6rem;background:#e9ecef;border-radius:4px;overflow:hidden;margin:.2rem 0 .6rem}.bar i{display:block;height:100%;background:var(--c)}
table{width:100%;border-collapse:collapse;font-size:.88rem}td,th{padding:.35rem;border-bottom:1px solid #eee;text-align:left}
#foto-preview{max-width:100%;max-height:260px;margin:.5rem 0;border-radius:8px}
.foot{text-align:center;padding:1rem}
.katex{font-size:1.08em}
.ai{background:#f3f0ff;border:1px solid #d0bfff;border-radius:10px;padding:.7rem;margin:.6rem 0;white-space:pre-wrap}
@media (max-width:520px){main{padding:.5rem}.card{padding:.8rem}.tabs button{padding:.7rem .6rem;font-size:.88rem}}