:root{--ink:#172033;--muted:#6d7688;--line:#e4e8ef;--blue:#3478f6;--bg:#f5f7fb}*{box-sizing:border-box}body{margin:0;min-height:100vh;color:var(--ink);background:radial-gradient(circle at 15% 10%,#eaf1ff 0,#f5f7fb 38%),var(--bg);font-family:system-ui,-apple-system,"Noto Sans JP",sans-serif}.auth-shell{max-width:980px;margin:auto;min-height:100vh;display:grid;grid-template-columns:1fr 390px;gap:70px;align-items:center;padding:32px}.brand span{color:var(--blue);font-size:12px;font-weight:800;letter-spacing:.18em}.brand h1{font-size:clamp(34px,5vw,60px);line-height:1.08;letter-spacing:-.06em;margin:16px 0}.brand p{color:var(--muted)}.auth-card{background:#fff;border:1px solid var(--line);border-radius:20px;padding:25px;box-shadow:0 20px 60px #17203312}.tabs{display:grid;grid-template-columns:1fr 1fr;gap:4px;background:#f3f5f8;border-radius:10px;padding:4px;margin-bottom:25px}.tab{border:0;background:transparent;padding:10px;border-radius:8px;color:var(--muted);font-weight:700;cursor:pointer}.tab.active{background:#fff;color:var(--ink);box-shadow:0 2px 7px #17203314}.auth-form h2{margin:0 0 8px}.hint{color:var(--muted);font-size:13px;margin:0 0 20px}.auth-form label{display:block;font-size:13px;font-weight:700;margin:14px 0}.auth-form input{display:block;width:100%;border:1px solid var(--line);border-radius:9px;padding:12px;margin-top:7px;font:inherit}.auth-form small{display:block;color:var(--muted);font-weight:400;margin-top:5px}.primary{width:100%;margin-top:10px;border:0;border-radius:10px;padding:13px;background:var(--ink);color:#fff;font-weight:800;cursor:pointer}.primary:disabled{opacity:.55;cursor:wait}.message{min-height:22px;color:var(--muted);font-size:13px;line-height:1.6;margin:18px 0 0}.message.error{color:#bd4141}.hidden{display:none}@media(max-width:760px){.auth-shell{grid-template-columns:1fr;gap:20px;align-content:center;padding:22px}.brand h1{font-size:39px}.brand p{margin-bottom:8px}}