/* Link Biz - ログイン画面スタイル */
.login-overlay{position:fixed;inset:0;background:linear-gradient(135deg,#16162a 0%,#0f0f1f 60%,#1a1a35 100%);display:none;align-items:center;justify-content:center;z-index:1000;padding:1rem}
.login-overlay:not([hidden]){display:flex}
.login-card{background:#fff;border-radius:1rem;padding:2.5rem;width:100%;max-width:22rem;box-shadow:0 20px 60px rgba(0,0,0,.3)}
.login-logo{text-align:center;margin-bottom:2rem}
.login-logo-icon{width:4rem;height:4rem;background:var(--color-primary);border-radius:.875rem;display:flex;align-items:center;justify-content:center;font-size:1.75rem;color:#fff;margin:0 auto .75rem}
.login-title{font-size:1.5rem;font-weight:800;color:var(--text-primary);letter-spacing:.04em;margin-bottom:.25rem}
.login-subtitle{font-size:var(--font-size-sm);color:var(--text-muted)}
.login-form{display:flex;flex-direction:column;gap:0}
.login-error{display:none;align-items:center;gap:.5rem;padding:.6rem .85rem;background:#fee2e2;color:#991b1b;border-radius:var(--border-radius);font-size:var(--font-size-sm);margin-bottom:.75rem}
.login-error:not([hidden]){display:flex}
.btn-login{width:100%;padding:.7rem;background:var(--color-primary);color:#fff;border:none;border-radius:var(--border-radius);font-size:var(--font-size-base);font-weight:700;cursor:pointer;transition:background var(--transition);display:flex;align-items:center;justify-content:center;gap:.5rem;margin-top:.25rem}
.btn-login:hover{background:var(--color-primary-dark)}
.btn-login:disabled{opacity:.65;cursor:not-allowed}