.tool-container{max-width:900px;margin:0 auto;padding:var(--spacing-loose)}.tool-card{background:var(--bg-primary);border-radius:12px;box-shadow:0 2px 8px #00000014;padding:var(--spacing-loose);transition:box-shadow .2s ease-in-out}.tool-card:hover{box-shadow:0 4px 16px #0000001f}.tool-title{font-size:24px;font-weight:600;color:var(--text-primary);margin-bottom:var(--spacing-loose);line-height:1.3}.mode-switch{display:flex;gap:var(--spacing-tight);margin-bottom:var(--spacing-loose);background:var(--bg-secondary);padding:4px;border-radius:8px}.mode-btn{flex:1;padding:10px 20px;background:transparent;color:var(--text-secondary);border:none;border-radius:6px;font-size:14px;font-weight:500;cursor:pointer;transition:all .2s ease-in-out}.mode-btn:hover{color:var(--text-primary);background:#ffffff80}.mode-btn.active{background:var(--bg-primary);color:var(--primary);box-shadow:0 1px 3px #0000001a}.split-layout{display:grid;grid-template-columns:1fr 1fr;gap:var(--spacing-loose);margin-bottom:var(--spacing-standard)}.input-panel,.output-panel{display:flex;flex-direction:column}.input-label{display:block;font-size:14px;font-weight:500;color:var(--text-primary);margin-bottom:var(--spacing-tight);line-height:1.6}.input-textarea,.output-textarea{width:100%;min-height:200px;max-height:400px;padding:12px 16px;border:1px solid var(--border-primary);border-radius:8px;font-family:Consolas,Monaco,Courier New,monospace;font-size:14px;line-height:1.6;color:var(--text-primary);background:var(--bg-primary);resize:vertical;outline:none;transition:all .2s ease-in-out}.input-textarea:focus,.output-textarea:focus{border-color:var(--primary);box-shadow:0 0 0 3px #3b82f633}.input-textarea.error{border-color:var(--error);box-shadow:0 0 0 3px #ef444433}.input-textarea::placeholder,.output-textarea::placeholder{color:var(--text-tertiary)}.output-textarea{background:var(--bg-secondary)}.error-message{display:none;color:var(--error);font-size:12px;margin-top:var(--spacing-tight);line-height:1.5;animation:slideIn .3s ease-out}.error-message.show{display:block}@keyframes slideIn{0%{opacity:0;transform:translateY(-8px)}to{opacity:1;transform:translateY(0)}}.option-section{margin-top:var(--spacing-standard)}.checkbox-label{display:flex;align-items:center;gap:var(--spacing-tight);cursor:pointer;font-size:14px;color:var(--text-secondary)}.checkbox-label input[type=checkbox]{width:18px;height:18px;cursor:pointer;accent-color:var(--primary)}.checkbox-text{-webkit-user-select:none;user-select:none}.output-actions{margin-top:var(--spacing-tight);display:flex;justify-content:flex-end}.btn-copy-result{background:transparent;color:var(--text-tertiary);border:1px solid var(--border-primary);border-radius:6px;padding:6px 16px;font-size:13px;font-weight:500;cursor:pointer;transition:all .2s ease-in-out}.btn-copy-result:hover{color:var(--primary);border-color:var(--primary)}.btn-copy-result.copied{color:var(--success);border-color:var(--success)}.button-section{display:flex;gap:var(--spacing-tight);margin-top:var(--spacing-standard)}.btn-encode{background:#3b82f6;color:#fff;border-radius:8px;padding:10px 24px;font-size:14px;font-weight:500;cursor:pointer;transition:all .2s ease-in-out;border:none;outline:none}.btn-encode:hover{background:#2563eb;transform:translateY(-2px)}.btn-encode:active{background:#1d4ed8;transform:translateY(1px)}.btn-decode{background:#22c55e;color:#fff;border-radius:8px;padding:10px 24px;font-size:14px;font-weight:500;cursor:pointer;transition:all .2s ease-in-out;border:none;outline:none}.btn-decode:hover{background:#16a34a;transform:translateY(-2px)}.btn-decode:active{background:#15803d;transform:translateY(1px)}.btn-secondary{background:var(--text-tertiary);color:#fff;border-radius:8px;padding:10px 24px;font-size:14px;font-weight:500;cursor:pointer;transition:all .2s ease-in-out;border:none;outline:none}.btn-secondary:hover{background:#7b8a9a;transform:translateY(-2px)}.btn-secondary:active{background:#6b7a8a;transform:translateY(1px)}.file-drop-zone{border:2px dashed var(--border-primary);border-radius:8px;padding:var(--spacing-extra);text-align:center;cursor:pointer;transition:all .2s ease-in-out;background:var(--bg-secondary);min-height:200px;display:flex;align-items:center;justify-content:center}.file-drop-zone:hover{border-color:var(--primary);background:#3b82f60d}.file-drop-zone.drag-over{border-color:var(--primary);background:#3b82f61a}.file-drop-zone.error{border-color:var(--error)}.file-drop-zone.has-file{border-color:var(--success);background:#22c55e0d}.drop-content{pointer-events:none}.upload-icon{margin-bottom:var(--spacing-standard)}.drop-text{color:var(--text-secondary);font-size:14px}.file-input{display:none}.file-info{margin-top:var(--spacing-standard);padding:var(--spacing-standard);background:var(--bg-secondary);border-radius:8px;animation:fadeIn .3s ease-out}.file-info.hidden{display:none}.info-item{display:flex;align-items:center;padding:var(--spacing-tight) 0;border-bottom:1px solid var(--border-primary)}.info-item:last-child{border-bottom:none}.info-label{font-size:13px;font-weight:500;color:var(--text-secondary);min-width:60px}.info-value{font-size:13px;color:var(--text-primary);word-break:break-all}.hidden{display:none!important}@keyframes fadeIn{0%{opacity:0;transform:translateY(8px)}to{opacity:1;transform:translateY(0)}}.navbar{background:var(--bg-primary);box-shadow:0 2px 8px #00000014;position:sticky;top:0;z-index:100}.navbar-container{display:flex;align-items:center;justify-content:space-between;padding:var(--spacing-standard) 0}.logo{display:flex;align-items:center;gap:var(--spacing-standard);cursor:pointer;transition:all .2s ease-in-out}.logo:hover{transform:translateY(-2px)}.logo span{font-size:20px;font-weight:600;color:var(--text-primary)}.nav-links{display:flex;gap:var(--spacing-loose)}.nav-links a{color:var(--text-secondary);font-weight:500}.main-content{min-height:calc(100vh - 300px);padding:var(--spacing-extra) 0}.footer{background:var(--bg-tertiary);padding:var(--spacing-extra) 0;margin-top:var(--spacing-extra)}.footer-container{display:grid;grid-template-columns:repeat(4,1fr);gap:var(--spacing-loose)}.footer-column h3{font-size:16px;font-weight:600;color:var(--text-primary);margin-bottom:var(--spacing-standard)}.footer-column p{color:var(--text-secondary);font-size:14px;line-height:1.6;margin-bottom:var(--spacing-tight)}.footer-column ul{list-style:none}.footer-column ul li{margin-bottom:var(--spacing-tight)}.footer-column ul li a{color:var(--text-secondary);font-size:14px}.footer-column ul li a:hover{color:var(--primary)}.copyright{margin-top:var(--spacing-standard);font-size:12px;color:var(--text-tertiary)}@media(max-width:767px){.tool-container,.tool-card{padding:var(--spacing-standard)}.tool-title{font-size:20px}.split-layout{grid-template-columns:1fr;gap:var(--spacing-standard)}.input-textarea,.output-textarea{min-height:150px}.button-section{flex-direction:column}.btn-encode,.btn-decode,.btn-secondary{width:100%}.mode-switch{flex-direction:column}.file-drop-zone{min-height:150px;padding:var(--spacing-loose)}.navbar-container{flex-wrap:wrap}.logo{width:100%;justify-content:center;margin-bottom:var(--spacing-standard)}.nav-links{width:100%;justify-content:center}.footer-container{grid-template-columns:1fr}}