.b2a-tool{display:flex;flex-direction:column;gap:1.25rem;margin-bottom:2rem;}
.b2a-panel{background:var(--surface,#fff);border:1px solid var(--border-color,#e5e7eb);border-radius:12px;padding:1.25rem;box-shadow:0 1px 3px rgba(0,0,0,.06);}
.b2a-panel-input .b2a-form{display:flex;flex-direction:column;gap:1rem;}
.b2a-hint{display:flex;align-items:flex-start;gap:0.5rem;font-size:0.875rem;color:var(--text-muted);margin:0 0 0.25rem;padding:0.75rem 1rem;background:var(--surface-muted,#f9fafb);border-radius:8px;border-left:3px solid var(--primary,#2563eb);}
.b2a-hint-icon{flex-shrink:0;color:var(--primary,#2563eb);}
.b2a-field{display:flex;flex-direction:column;gap:0.375rem;}
.b2a-label{display:inline-flex;align-items:center;gap:0.5rem;font-weight:600;font-size:0.9375rem;color:var(--text-main,#111);}
.b2a-label-text{flex:1;}
.b2a-tooltip-wrap{position:relative;}
.tooltip-trigger{width:1.25rem;height:1.25rem;padding:0;border-radius:50%;border:1px solid var(--border-color);background:var(--surface);color:var(--text-muted);font-size:0.7rem;font-weight:700;cursor:help;display:inline-flex;align-items:center;justify-content:center;}
.tooltiptext{visibility:hidden;opacity:0;position:absolute;bottom:100%;left:0;margin-bottom:4px;padding:0.5rem 0.75rem;font-size:0.8125rem;font-weight:400;color:var(--text-main);background:var(--surface);border:1px solid var(--border-color);border-radius:6px;box-shadow:0 4px 12px rgba(0,0,0,.1);white-space:normal;max-width:280px;z-index:10;transition:visibility .15s,opacity .15s;}
.tooltip-trigger:hover+.tooltiptext,.tooltip-trigger:focus+.tooltiptext,.tooltiptext:hover{visibility:visible;opacity:1;}
.b2a-textarea{width:100%;min-height:180px;padding:0.875rem 1rem;font-size:0.875rem;font-family:ui-monospace,monospace;line-height:1.5;color:var(--text-main);background:var(--surface);border:1px solid var(--border-color);border-radius:8px;resize:vertical;transition:border-color .2s,box-shadow .2s;}
.b2a-textarea:focus{outline:0;border-color:var(--primary);box-shadow:0 0 0 3px rgba(37,99,235,.15);}
.b2a-textarea::placeholder{color:var(--text-muted);}
.b2a-meta{font-size:0.8125rem;color:var(--text-muted);}
.b2a-meta i{margin-right:0.375rem;}
.b2a-actions{display:flex;flex-wrap:wrap;gap:0.5rem;}
.b2a-btn{display:inline-flex;align-items:center;gap:0.5rem;padding:0.5rem 0.875rem;font-size:0.875rem;font-weight:500;border-radius:8px;border:1px solid transparent;cursor:pointer;transition:background .2s,color .2s,border-color .2s;}
.b2a-btn-ghost{background:transparent;color:var(--text-main);border-color:var(--border-color);}
.b2a-btn-ghost:hover{background:var(--surface-muted,#f3f4f6);}
.b2a-btn-primary{background:var(--primary,#2563eb);color:#fff;border-color:var(--primary);}
.b2a-btn-primary:hover:not(:disabled){background:var(--primary-dark,#1d4ed8);}
.b2a-btn-primary:disabled{opacity:0.6;cursor:not-allowed;}
.b2a-btn.copied{background:var(--accent,#059669);border-color:var(--accent);color:#fff;}
.b2a-panel-output{min-height:200px;}
.b2a-empty{display:flex;align-items:center;justify-content:center;padding:2rem;}
.b2a-empty-inner{text-align:center;max-width:320px;}
.b2a-empty-icon{display:inline-block;color:var(--text-muted);opacity:0.7;margin-bottom:0.75rem;}
.b2a-empty-title{font-size:1.125rem;font-weight:600;margin:0 0 0.375rem;color:var(--text-main);}
.b2a-empty-desc{font-size:0.875rem;color:var(--text-muted);margin:0;}
.b2a-results{display:flex;flex-direction:column;gap:1rem;}
.b2a-results-head{margin:0;}
.b2a-results-title{font-size:1rem;font-weight:600;margin:0;color:var(--text-main);}
.b2a-player-wrap{min-height:140px;padding:1.25rem;background:var(--surface-muted,#f8fafc);border-radius:8px;border:1px dashed var(--border-color);display:flex;flex-direction:column;align-items:center;justify-content:center;}
.b2a-player-wrap:hover{border-color:var(--primary);}
.b2a-output-meta{margin-top:0.25rem;}
.b2a-result-actions{padding-top:1rem;border-top:1px solid var(--border-color);}
.b2a-action-row{display:flex;flex-wrap:wrap;gap:0.5rem;align-items:center;}
.b2a-share{margin-top:1rem;}
.b2a-share-title{font-size:0.8125rem;font-weight:600;color:var(--text-muted);margin:0 0 0.5rem;}
.b2a-share-btns{display:flex;flex-wrap:wrap;gap:0.5rem;}
.b2a-share-btn{display:inline-flex;align-items:center;gap:0.375rem;padding:0.375rem 0.625rem;font-size:0.8125rem;color:var(--text-main);background:var(--surface-muted);border-radius:6px;text-decoration:none;transition:background .2s;}
.b2a-share-btn:hover{background:var(--border-color);}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0;}
.preview-placeholder{text-align:center;color:var(--text-muted);}
.preview-placeholder i{opacity:0.5;margin-bottom:0.5rem;}
.preview-placeholder .mt-2{margin-top:0.5rem;margin-bottom:0;font-size:0.875rem;}
.audio-player{width:100%;max-width:100%;margin:0.75rem 0;border-radius:8px;}
.audio-info{font-size:0.8125rem;font-weight:500;color:var(--text-main);background:var(--surface);border:1px solid var(--border-color);padding:0.5rem 0.75rem;border-radius:6px;margin-top:0.5rem;text-align:center;}
.waveform-visualization{width:100%;max-width:100%;height:64px;background:linear-gradient(135deg,var(--primary,#2563eb) 0%,var(--primary-dark,#1d4ed8) 100%);margin:0.5rem 0;border-radius:8px;overflow:hidden;}
.waveform-bars{display:flex;align-items:flex-end;height:100%;padding:8px 12px;gap:2px;justify-content:center;}
.waveform-bar{background:rgba(255,255,255,.85);border-radius:2px;flex:1;min-width:3px;min-height:10%;animation:b2a-pulse 1.5s ease-in-out infinite alternate;}
.waveform-bar:nth-child(odd){animation-delay:.1s;}
.waveform-bar:nth-child(even){animation-delay:.2s;}
@keyframes b2a-pulse{0%{opacity:.5;transform:scaleY(.8);}100%{opacity:1;transform:scaleY(1);}}
.b2a-edu{margin-top:2.5rem;padding:2rem 0;}
.b2a-edu-inner{background:var(--surface,#fff);border:1px solid var(--border-color,#e5e7eb);border-radius:12px;padding:1.5rem 1.25rem;box-shadow:0 1px 3px rgba(0,0,0,.06);}
.b2a-edu-inner h2{font-size:1.5rem;font-weight:700;margin:0 0 0.75rem;color:var(--text-main);}
.b2a-edu-inner p{margin:0 0 1rem;font-size:1rem;line-height:1.6;color:var(--text-main);}
.b2a-edu-inner code{font-size:0.875em;padding:0.15em 0.4em;background:var(--surface-muted,#f9fafb);border:1px solid var(--border-color);border-radius:4px;}
.b2a-edu-h3{font-size:1.125rem;font-weight:600;margin:1.5rem 0 0.5rem;color:var(--text-main);}
.b2a-edu-inner a{color:var(--primary);text-decoration:underline;}
.b2a-edu-inner a:hover{text-decoration:none;}
@media (min-width:768px){.b2a-edu-inner{padding:2rem 2.25rem;}}
@media (min-width:768px){.b2a-tool{gap:1.5rem;}.b2a-panel{padding:1.5rem;}.b2a-textarea{min-height:220px;}.b2a-player-wrap{min-height:200px;padding:1.5rem;}}
@media (min-width:992px){.b2a-tool{display:grid;grid-template-columns:1fr 1fr;align-items:stretch;gap:1.5rem;}.b2a-panel-input{grid-column:1;grid-row:1;}.b2a-panel-output{grid-column:2;grid-row:1;}}