:root{--primary-color: #667eea;--primary-dark: #5a67d8;--secondary-color: #764ba2;--accent-color: #f093fb;--success-color: #48bb78;--error-color: #f56565;--warning-color: #ed8936;--info-color: #4299e1;--bg-primary: #ffffff;--bg-secondary: #f8fafc;--bg-tertiary: #edf2f7;--text-primary: #2d3748;--text-secondary: #4a5568;--text-muted: #718096;--border-color: #e2e8f0;--shadow-color: rgba(0, 0, 0, .1);--dark-bg-primary: #1a202c;--dark-bg-secondary: #2d3748;--dark-bg-tertiary: #4a5568;--dark-text-primary: #f7fafc;--dark-text-secondary: #e2e8f0;--dark-text-muted: #a0aec0;--dark-border-color: #4a5568;--dark-shadow-color: rgba(0, 0, 0, .3);--spacing-xs: .25rem;--spacing-sm: .5rem;--spacing-md: 1rem;--spacing-lg: 1.5rem;--spacing-xl: 2rem;--spacing-2xl: 3rem;--font-family-primary: "Poppins", -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", sans-serif;--font-size-xs: .75rem;--font-size-sm: .875rem;--font-size-md: 1rem;--font-size-lg: 1.125rem;--font-size-xl: 1.25rem;--font-size-2xl: 1.5rem;--font-size-3xl: 2rem;--radius-sm: .375rem;--radius-md: .5rem;--radius-lg: .75rem;--radius-xl: 1rem;--transition-fast: .15s ease;--transition-normal: .3s ease;--transition-slow: .5s ease;--z-dropdown: 10;--z-sticky: 20;--z-fixed: 30;--z-modal: 40;--z-toast: 50}[data-theme=dark]{--bg-primary: var(--dark-bg-primary);--bg-secondary: var(--dark-bg-secondary);--bg-tertiary: var(--dark-bg-tertiary);--text-primary: var(--dark-text-primary);--text-secondary: var(--dark-text-secondary);--text-muted: var(--dark-text-muted);--border-color: var(--dark-border-color);--shadow-color: var(--dark-shadow-color)}*,*:before,*:after{box-sizing:border-box;margin:0;padding:0}html{font-size:16px;scroll-behavior:smooth}body{font-family:var(--font-family-primary);font-size:var(--font-size-md);line-height:1.6;color:var(--text-primary);background-color:var(--bg-primary);transition:background-color var(--transition-normal),color var(--transition-normal)}h1,h2,h3,h4,h5,h6{font-weight:600;line-height:1.3;margin-bottom:var(--spacing-sm)}h1{font-size:var(--font-size-3xl)}h2{font-size:var(--font-size-2xl)}h3{font-size:var(--font-size-xl)}h4{font-size:var(--font-size-lg)}p{margin-bottom:var(--spacing-md)}a{color:var(--primary-color);text-decoration:none;transition:color var(--transition-fast)}a:hover{color:var(--primary-dark)}button{font-family:inherit;font-size:inherit;border:none;background:none;cursor:pointer;transition:all var(--transition-fast)}input,select,textarea{font-family:inherit;font-size:inherit;border:1px solid var(--border-color);border-radius:var(--radius-md);padding:var(--spacing-sm) var(--spacing-md);background-color:var(--bg-primary);color:var(--text-primary);transition:all var(--transition-fast)}input:focus,select:focus,textarea:focus{outline:none;border-color:var(--primary-color);box-shadow:0 0 0 3px #667eea1a}.hidden{display:none!important}.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}.text-center{text-align:center}.text-left{text-align:left}.text-right{text-align:right}.font-light{font-weight:300}.font-normal{font-weight:400}.font-medium{font-weight:500}.font-semibold{font-weight:600}.font-bold{font-weight:700}.text-xs{font-size:var(--font-size-xs)}.text-sm{font-size:var(--font-size-sm)}.text-md{font-size:var(--font-size-md)}.text-lg{font-size:var(--font-size-lg)}.text-xl{font-size:var(--font-size-xl)}@media (max-width: 768px){:root{--font-size-3xl: 1.75rem;--font-size-2xl: 1.375rem;--spacing-xl: 1.5rem;--spacing-2xl: 2rem}}@keyframes fadeIn{0%{opacity:0}to{opacity:1}}@keyframes slideUp{0%{opacity:0;transform:translateY(20px)}to{opacity:1;transform:translateY(0)}}@keyframes pulse{0%,to{opacity:1}50%{opacity:.5}}@keyframes spin{0%{transform:rotate(0)}to{transform:rotate(360deg)}}.animate-fade-in{animation:fadeIn var(--transition-normal)}.animate-slide-up{animation:slideUp var(--transition-normal)}.animate-pulse{animation:pulse 2s infinite}.animate-spin{animation:spin 1s linear infinite}.converter-form{background:var(--bg-secondary);padding:var(--spacing-xl);border-radius:var(--radius-xl);box-shadow:0 10px 25px var(--shadow-color);margin-bottom:var(--spacing-xl);transition:all var(--transition-normal)}.converter-form:hover{transform:translateY(-2px);box-shadow:0 15px 35px var(--shadow-color)}.input-group{display:flex;gap:var(--spacing-md);margin-bottom:var(--spacing-lg);align-items:stretch}.url-input{flex:1;padding:var(--spacing-md) var(--spacing-lg);font-size:var(--font-size-md);border:2px solid var(--border-color);border-radius:var(--radius-lg);background:var(--bg-primary);color:var(--text-primary);transition:all var(--transition-normal)}.url-input:focus{border-color:var(--primary-color);box-shadow:0 0 0 3px #667eea1a;transform:scale(1.02)}.url-input.valid{border-color:var(--success-color);background-color:#48bb780d}.url-input.invalid{border-color:var(--error-color);background-color:#f565650d}.url-input::-moz-placeholder{color:var(--text-muted)}.url-input::placeholder{color:var(--text-muted)}.convert-btn{padding:var(--spacing-md) var(--spacing-xl);background:linear-gradient(135deg,var(--primary-color),var(--secondary-color));color:#fff;border:none;border-radius:var(--radius-lg);font-weight:600;font-size:var(--font-size-md);cursor:pointer;transition:all var(--transition-normal);white-space:nowrap;min-width:120px;display:flex;align-items:center;justify-content:center;gap:var(--spacing-xs)}.convert-btn:hover:not(:disabled){transform:translateY(-2px);box-shadow:0 10px 25px #667eea4d;background:linear-gradient(135deg,var(--primary-dark),var(--secondary-color))}.convert-btn:active:not(:disabled){transform:translateY(0)}.convert-btn:disabled{opacity:.6;cursor:not-allowed;background:var(--text-muted)}.convert-btn.loading{position:relative;color:transparent}.convert-btn.loading:after{content:"";position:absolute;top:50%;left:50%;transform:translate(-50%,-50%);width:20px;height:20px;border:2px solid transparent;border-top:2px solid white;border-radius:50%;animation:spin 1s linear infinite}.quality-selector{display:flex;align-items:center;gap:var(--spacing-md)}.quality-selector label{font-weight:500;color:var(--text-secondary);min-width:100px}.audio-quality{flex:1;max-width:200px;padding:var(--spacing-sm) var(--spacing-md);border:2px solid var(--border-color);border-radius:var(--radius-md);background:var(--bg-primary);color:var(--text-primary);cursor:pointer;transition:all var(--transition-fast)}.audio-quality:focus{border-color:var(--primary-color);box-shadow:0 0 0 3px #667eea1a}.audio-quality:hover{border-color:var(--primary-color)}.validation-message{margin-top:var(--spacing-sm);padding:var(--spacing-sm) var(--spacing-md);border-radius:var(--radius-sm);font-size:var(--font-size-sm);display:flex;align-items:center;gap:var(--spacing-xs)}.validation-message.error{background-color:#f565651a;color:var(--error-color);border:1px solid rgba(245,101,101,.2)}.validation-message.success{background-color:#48bb781a;color:var(--success-color);border:1px solid rgba(72,187,120,.2)}@media (max-width: 768px){.converter-form{padding:var(--spacing-lg);margin-bottom:var(--spacing-lg)}.input-group{flex-direction:column;gap:var(--spacing-sm)}.convert-btn{width:100%;padding:var(--spacing-md)}.quality-selector{flex-direction:column;align-items:stretch;gap:var(--spacing-sm)}.quality-selector label{min-width:auto}.audio-quality{max-width:none}}@media (max-width: 480px){.converter-form{padding:var(--spacing-md)}.url-input,.convert-btn{padding:var(--spacing-sm) var(--spacing-md);font-size:var(--font-size-sm)}}.converter-form.submitting{pointer-events:none}.converter-form.submitting .url-input{background-color:var(--bg-tertiary)}.converter-form.error{border:2px solid var(--error-color);background-color:#f5656505}.converter-form.success{border:2px solid var(--success-color);background-color:#48bb7805}.converter-form:focus-within{outline:2px solid var(--primary-color);outline-offset:2px}@media (prefers-reduced-motion: reduce){.converter-form,.url-input,.convert-btn,.audio-quality{transition:none}.convert-btn:hover:not(:disabled){transform:none}}