*,*::before,*::after{margin:0;padding:0;box-sizing:border-box}
:root{--bg:#0F1219;--card:rgba(15,18,25,0.8);--border:rgba(99,102,241,0.12);--primary:#6366F1;--primary-l:#818CF8;--text:#E2E8F0;--muted:#94A3B8;--dim:#475569;--r:12px;--rs:8px;--font:'Inter',system-ui,sans-serif}
body{font-family:var(--font);background:var(--bg);color:var(--text);min-height:100vh;display:flex;align-items:center;justify-content:center;-webkit-font-smoothing:antialiased}
body::before{content:'';position:fixed;inset:0;pointer-events:none;background:radial-gradient(ellipse 50% 40% at 50% 20%,rgba(99,102,241,0.05),transparent 70%)}
.app{max-width:480px;width:100%;padding:20px;position:relative;z-index:1}
h1{font-size:1.3rem;font-weight:700;text-align:center;margin-bottom:16px;background:linear-gradient(135deg,var(--primary),var(--primary-l));-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}
.panel{background:var(--card);border:1px solid var(--border);border-radius:var(--r);padding:16px;backdrop-filter:blur(12px);margin-bottom:12px}
.panel h3{font-size:0.85rem;font-weight:600;margin-bottom:8px;color:var(--muted)}
.form-row{margin-bottom:8px}
.form-row label{display:block;font-size:0.78rem;color:var(--dim);margin-bottom:4px}
.form-row select,.form-row input{width:100%;background:rgba(0,0,0,0.3);border:1px solid var(--border);border-radius:var(--rs);padding:10px 12px;font-family:var(--font);font-size:0.9rem;color:var(--text);color-scheme:dark}
.form-row select:focus,.form-row input:focus{outline:none;border-color:var(--primary)}
.swap-row{text-align:center;margin:6px 0}
.btn-swap{background:rgba(99,102,241,0.08);border:1px solid var(--border);color:var(--primary-l);padding:6px 16px;border-radius:20px;cursor:pointer;font-size:1rem;transition:all 200ms}
.btn-swap:hover{background:rgba(99,102,241,0.15)}
.formula{font-size:0.78rem;color:var(--dim);text-align:center;margin-top:8px;font-family:'SF Mono',monospace}
.history{max-height:150px;overflow-y:auto;display:flex;flex-direction:column;gap:4px}
.hist-item{font-size:0.78rem;color:var(--muted);padding:4px 8px;background:rgba(0,0,0,0.15);border-radius:4px}
.footer{text-align:center;color:var(--dim);font-size:0.7rem;margin-top:16px}