:root{--bopi-brand:orange;--bopi-brand-dark:#c70;--bopi-brand-light:#fff3d6;--bopi-brand-grad:linear-gradient(135deg, #ff7a00, #ffd600);--bopi-dark:#111;--bopi-dark-hover:#333;--bopi-root-key:#ff7a00;--bopi-chord-key:#ffd600;--bopi-bg:#f7f7f4;--bopi-card:#fff;--bopi-stage:#1e1e1e;--bopi-ink:#111;--bopi-mid:#555;--bopi-soft:#888;--bopi-faint-text:#aaa;--bopi-faint:#e0e0e0;--bopi-soft-line:#f0f0f0;--bopi-success:#3e7c3e;--bopi-danger:#c0392b;--bopi-playing:#4a9eca;--bopi-font-label:11px;--bopi-font-small:12px;--bopi-font-body:15px;--bopi-font-lead:17px;--bopi-font-title:22px;--bopi-font-display:28px;--bopi-family-body:"Apple SD Gothic Neo", "Noto Sans KR", "Malgun Gothic", sans-serif;--bopi-family-mono:"SFMono-Regular", Consolas, monospace;--bopi-radius-sm:8px;--bopi-radius-md:12px;--bopi-radius-lg:14px;--bopi-radius-pill:20px;--bopi-shadow-card:0 1px 3px #1111110d;--bopi-shadow-raised:0 4px 16px #1111111f}.bopi-grad-text{background:var(--bopi-brand-grad);-webkit-text-fill-color:transparent;-webkit-background-clip:text;background-clip:text}.bopi-tag{background:var(--bopi-brand-grad);color:var(--bopi-dark);font-size:var(--bopi-font-label);letter-spacing:.08em;border-radius:var(--bopi-radius-pill);padding:3px 12px;font-weight:800;display:inline-block}.bopi-label{font-size:var(--bopi-font-label);color:var(--bopi-faint-text);letter-spacing:.08em;text-transform:uppercase;font-weight:700}.bopi-btn{font-family:var(--bopi-family-body);font-size:var(--bopi-font-body);border-radius:var(--bopi-radius-lg);cursor:pointer;border:2px solid #0000;justify-content:center;align-items:center;gap:8px;min-height:48px;padding:12px 24px;font-weight:700;transition:all .15s;display:inline-flex}.bopi-btn:active{transform:translateY(1px)}.bopi-btn:focus-visible{outline:3px solid var(--bopi-brand);outline-offset:2px}.bopi-btn:disabled{opacity:.4;cursor:not-allowed}.bopi-btn--primary{background:var(--bopi-dark);color:#fff}.bopi-btn--primary:hover:not(:disabled){background:var(--bopi-dark-hover)}.bopi-btn--secondary{background:var(--bopi-card);color:var(--bopi-ink);border-color:var(--bopi-faint)}.bopi-btn--secondary:hover:not(:disabled){border-color:var(--bopi-brand)}.bopi-btn--ghost{color:var(--bopi-mid);background:0 0}.bopi-btn--ghost:hover:not(:disabled){background:var(--bopi-soft-line)}.bopi-btn--danger{background:var(--bopi-danger);color:#fff}.bopi-btn--big{min-height:56px;font-size:var(--bopi-font-lead);width:100%;padding:16px 32px}.bopi-choice{border:2px solid var(--bopi-faint);border-radius:var(--bopi-radius-md);background:var(--bopi-card);cursor:pointer;text-align:center;padding:14px 8px 12px;font-family:inherit;transition:all .12s}.bopi-choice:hover{border-color:var(--bopi-soft);transform:translateY(-1px)}.bopi-choice.selected{background:var(--bopi-dark);border-color:var(--bopi-dark);transform:none}.bopi-choice .bopi-choice__main{font-size:var(--bopi-font-title);color:var(--bopi-ink);font-weight:800;display:block}.bopi-choice.selected .bopi-choice__main{background:var(--bopi-brand-grad);-webkit-text-fill-color:transparent;-webkit-background-clip:text;background-clip:text}.bopi-choice .bopi-choice__sub{color:var(--bopi-faint-text);margin-top:3px;font-size:10px;display:block}.bopi-card{background:var(--bopi-card);border:1px solid var(--bopi-faint);border-radius:var(--bopi-radius-md);box-shadow:var(--bopi-shadow-card);padding:16px 18px}.bopi-card__title{font-size:var(--bopi-font-lead);color:var(--bopi-ink);margin:0 0 6px;font-weight:700}.bopi-card__desc{font-size:var(--bopi-font-body);color:var(--bopi-mid);margin:0;line-height:1.7}.bopi-stage{background:var(--bopi-stage);border-radius:var(--bopi-radius-lg);padding:14px 14px 16px}.bopi-stage__title{color:#fff;font-size:var(--bopi-font-body);font-weight:700}.bopi-stage__sub{color:#666;font-size:var(--bopi-font-small);margin-left:8px}.bopi-stage__head{margin-bottom:10px}.bopi-legend{flex-wrap:wrap;gap:14px;margin-top:10px;display:flex}.bopi-legend__item{font-size:var(--bopi-font-label);color:var(--bopi-soft);align-items:center;gap:5px;display:flex}.bopi-legend__dot{border-radius:2px;flex-shrink:0;width:12px;height:12px}.bopi-chord{font-size:var(--bopi-font-lead);color:var(--bopi-ink);background:var(--bopi-card);border:2px solid var(--bopi-faint);border-radius:var(--bopi-radius-sm);padding:4px 14px;font-weight:800;display:inline-block}.bopi-chord--active{background:var(--bopi-dark);border-color:var(--bopi-dark);color:#fff}.bopi-piano{-webkit-user-select:none;user-select:none;width:100%;height:auto;display:block}.bopi-piano__key{cursor:pointer}.bopi-piano__key:focus-visible{outline:3px solid var(--bopi-brand);outline-offset:-3px}.bopi-piano__label{font-family:var(--bopi-family-body);pointer-events:none;font-weight:600}*{box-sizing:border-box}body{background:var(--bopi-bg);color:var(--bopi-ink);font-family:var(--bopi-family-body);font-size:var(--bopi-font-body);margin:0}.shell-login{min-height:100vh;padding:var(--bopi-font-body);justify-content:center;align-items:center;display:flex}.shell-login__panel{background:var(--bopi-card);border:1px solid var(--bopi-faint);border-radius:var(--bopi-radius-lg);width:100%;max-width:380px;box-shadow:var(--bopi-shadow-raised);padding:32px 28px}.shell-login__head{text-align:center;margin-bottom:24px}.shell-login__title{font-size:var(--bopi-font-display);margin:14px 0 6px;font-weight:800}.shell-login__lead{color:var(--bopi-mid);margin:0}.shell-login__form{flex-direction:column;gap:10px;margin-bottom:18px;display:flex}.shell-login__error{color:var(--bopi-danger);border-radius:var(--bopi-radius-sm);font-size:var(--bopi-font-small);background:#fdecea;border:1px solid #f5c6c0;margin-bottom:14px;padding:10px 12px}.shell-login__divider{text-align:center;color:var(--bopi-soft);font-size:var(--bopi-font-small);margin:18px 0;position:relative}.shell-login__divider:before{content:"";background:var(--bopi-faint);height:1px;position:absolute;top:50%;left:0;right:0}.shell-login__divider span{background:var(--bopi-card);padding:0 10px;position:relative}.shell-login__note{font-size:var(--bopi-font-small);color:var(--bopi-mid);margin-top:20px}.shell-login__join{text-align:center;font-size:var(--bopi-font-small);color:var(--bopi-mid);margin:16px 0 0}.shell-login__join a{color:var(--bopi-brand-dark);font-weight:700}.shell-input{border:1px solid var(--bopi-faint);border-radius:var(--bopi-radius-sm);width:100%;font-size:var(--bopi-font-body);padding:11px 14px;font-family:inherit}.shell-input:focus{outline:2px solid var(--bopi-brand);border-color:#0000}.shell-home__bar,.shell-section .shell-home__bar{border-bottom:1px solid var(--bopi-faint);background:var(--bopi-card);justify-content:space-between;align-items:center;padding:14px 20px;display:flex}.shell-home__brand{font-size:var(--bopi-font-title);font-weight:800}.shell-home__left{align-items:center;min-width:80px;display:flex}.shell-home__user{justify-content:flex-end;align-items:center;gap:10px;min-width:80px;display:flex}.shell-home__email{font-size:var(--bopi-font-small);color:var(--bopi-mid)}.shell-home__main{max-width:880px;margin:0 auto;padding:32px 20px}.shell-notice{background:var(--bopi-brand-light);border:1px solid var(--bopi-brand);color:var(--bopi-brand-dark);border-radius:var(--bopi-radius-md);font-size:var(--bopi-font-small);margin-bottom:20px;padding:12px 16px}.shell-grid{grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:16px;margin-top:12px;display:grid}.shell-entry{text-align:left;background:var(--bopi-card);border:1px solid var(--bopi-faint);border-radius:var(--bopi-radius-lg);cursor:pointer;flex-direction:column;gap:6px;padding:22px 20px;font-family:inherit;transition:transform .12s,box-shadow .12s,border-color .12s;display:flex}.shell-entry:hover:not(:disabled){box-shadow:var(--bopi-shadow-raised);border-color:var(--bopi-brand);transform:translateY(-2px)}.shell-entry__emoji{font-size:34px}.shell-entry__title{font-size:var(--bopi-font-lead);font-weight:700}.shell-entry__desc{font-size:var(--bopi-font-small);color:var(--bopi-mid)}.shell-entry__lock{font-size:var(--bopi-font-small);color:var(--bopi-brand-dark);margin-top:4px}.shell-entry__badge{font-size:var(--bopi-font-label);color:var(--bopi-mid);background:var(--bopi-soft-line);border-radius:var(--bopi-radius-pill);align-self:flex-start;margin-top:6px;padding:2px 10px}.shell-entry--locked{opacity:.6;cursor:not-allowed}.shell-section__body{max-width:640px;margin:0 auto;padding:40px 20px}.shell-section__hint{color:var(--bopi-mid);font-size:var(--bopi-font-small);margin-top:10px}