.pc-wrap{margin-bottom:2rem;}
.pc-card{background:var(--surface,#fff);border:1px solid var(--border,#e5e7eb);border-radius:14px;box-shadow:0 2px 16px var(--shadow-soft,rgba(0,0,0,.06));padding:1.25rem;overflow:hidden;}
.pc-type-row{display:flex;flex-wrap:wrap;align-items:center;gap:0.75rem;margin-bottom:1.25rem;}
.pc-type-label{font-size:0.75rem;font-weight:600;color:var(--text-muted,#6b7280);text-transform:uppercase;letter-spacing:0.05em;}
.pc-type-tabs{display:flex;flex-wrap:wrap;gap:0.35rem;}
.pc-tab{padding:0.5rem 1rem;font-size:0.875rem;font-weight:600;color:var(--text-muted,#6b7280);background:var(--surface-muted,#f3f4f6);border:1px solid var(--border,#e5e7eb);border-radius:10px;cursor:pointer;transition:background .2s,border-color .2s,color .2s;}
.pc-tab:hover{color:var(--text-main,#111);border-color:var(--primary,#5e35b1);background:rgba(94,53,177,.06);}
.pc-tab-active,.pc-tab[aria-selected="true"]{color:#fff;background:var(--primary,#5e35b1);border-color:var(--primary,#5e35b1);}
.pc-tab-active:hover,.pc-tab[aria-selected="true"]:hover{background:var(--primary-dark,#4527a0);border-color:var(--primary-dark,#4527a0);color:#fff;}
.pc-equation{display:flex;flex-wrap:wrap;align-items:center;justify-content:center;gap:0.5rem 0.35rem;margin-bottom:0.75rem;}
.pc-eq-part{min-width:0;flex:1 1 4rem;max-width:6rem;}
.pc-input{width:100%;padding:0.75rem 0.65rem;font-size:1rem;font-family:ui-monospace,monospace;text-align:center;color:var(--text-main,#111);background:var(--surface,#fff);border:1px solid var(--border,#e5e7eb);border-radius:10px;box-sizing:border-box;transition:border-color .15s,box-shadow .15s;-webkit-appearance:none;appearance:none;}
.pc-input:focus{outline:none;border-color:var(--primary,#5e35b1);box-shadow:0 0 0 3px rgba(94,53,177,.12);}
.pc-input::placeholder{color:var(--text-muted,#9ca3af);}
.pc-input[readonly]{background:var(--surface-muted,#f3f4f6);color:var(--text-muted,#6b7280);}
.pc-eq-op,.pc-eq-eq{font-size:1.25rem;font-weight:600;color:var(--text-muted,#6b7280);flex-shrink:0;}
.pc-eq-eq{margin:0 0.1rem;}
.pc-eq-part-b2[hidden],.pc-eq-part-d[hidden]{display:none !important;}
.pc-hint{font-size:0.8125rem;color:var(--text-muted,#6b7280);margin:0 0 1rem;}
.pc-actions{display:flex;flex-wrap:wrap;gap:0.5rem;margin-bottom:1rem;}
.pc-btn{padding:0.6rem 1.25rem;font-size:0.9375rem;font-weight:600;border-radius:10px;cursor:pointer;transition:background .2s,border-color .2s,color .2s;border:1px solid transparent;}
.pc-btn-solve{color:#fff;background:var(--primary,#5e35b1);border-color:var(--primary,#5e35b1);}
.pc-btn-solve:hover{background:var(--primary-dark,#4527a0);border-color:var(--primary-dark,#4527a0);}
.pc-btn-copy{color:var(--text-main,#111);background:var(--surface,#fff);border-color:var(--border,#e5e7eb);}
.pc-btn-copy:hover{border-color:var(--primary,#5e35b1);color:var(--primary,#5e35b1);}
.pc-examples{display:flex;flex-wrap:wrap;align-items:center;gap:0.5rem;margin-bottom:1.25rem;}
.pc-examples-label{font-size:0.7rem;font-weight:600;color:var(--text-muted,#9ca3af);text-transform:uppercase;letter-spacing:0.04em;}
.pc-example{padding:0.35rem 0.65rem;font-size:0.8125rem;color:var(--primary,#5e35b1);background:transparent;border:1px solid var(--border,#e5e7eb);border-radius:8px;cursor:pointer;transition:background .15s,border-color .15s;}
.pc-example:hover{background:rgba(94,53,177,.08);border-color:var(--primary,#5e35b1);}
.pc-result{padding-top:1rem;border-top:1px solid var(--border,#e5e7eb);}
.pc-result[hidden]{display:none !important;}
.pc-answer{padding:0.875rem 1rem;background:var(--surface-muted,#f8f9fa);border:1px solid var(--border,#e5e7eb);border-radius:10px;font-size:1.125rem;font-weight:700;font-family:ui-monospace,monospace;color:var(--primary,#5e35b1);margin-bottom:0.75rem;}
.pc-steps-block{border:1px solid var(--border,#e5e7eb);border-radius:10px;overflow:hidden;background:var(--surface,#fff);margin-bottom:0.75rem;}
.pc-steps-heading{padding:0.75rem 1rem;font-size:0.9375rem;font-weight:600;color:var(--text-main,#111);margin:0;border-bottom:1px solid var(--border,#e5e7eb);}
.pc-steps-body{padding:1rem;font-size:0.875rem;line-height:1.6;color:var(--text-muted,#6b7280);}
.pc-step{padding:0.5rem 0 0.5rem 0.75rem;margin:0.35rem 0;border-left:3px solid var(--border,#e5e7eb);}
.pc-step.final{border-left-color:var(--primary,#5e35b1);background:rgba(94,53,177,.06);margin-left:-0.75rem;padding-left:0.75rem;border-radius:0 8px 8px 0;}
.pc-verify{padding:0.875rem 1rem;background:rgba(94,53,177,.06);border:1px solid rgba(94,53,177,.2);border-radius:10px;font-size:0.875rem;line-height:1.5;color:var(--text-muted,#6b7280);}
.pc-verify h6{font-size:0.8125rem;font-weight:600;color:var(--text-main,#111);margin:0 0 0.35rem;}
.pc-verify p{margin:0 0 0.25rem;}
.pc-verify p:last-child{margin-bottom:0;}
.pc-edu{margin-top:1.5rem;padding-top:1.5rem;border-top:1px solid var(--border,#e5e7eb);}
.pc-edu-h2{font-size:1.25rem;font-weight:700;color:var(--text-main,#111);margin:0 0 0.5rem;}
.pc-edu p{font-size:0.9375rem;color:var(--text-muted,#6b7280);line-height:1.6;margin:0;}
@media (min-width:480px){.pc-eq-part{max-width:5.5rem;}.pc-equation{gap:0.5rem 0.5rem;}}
@media (min-width:640px){.pc-card{padding:1.5rem;}.pc-equation{justify-content:flex-start;}.pc-eq-part{flex:0 1 5rem;max-width:6rem;}}