:root{--primary-color: #4f46e5;--primary-hover: #4338ca;--success-color: #10b981;--danger-color: #ef4444;--danger-hover: #dc2626;--gray-50: #f9fafb;--gray-100: #f3f4f6;--gray-200: #e5e7eb;--gray-300: #d1d5db;--gray-400: #9ca3af;--gray-500: #6b7280;--gray-700: #374151;--gray-800: #1f2937;--gray-900: #111827;--white: #ffffff;--shadow: 0 1px 3px 0 rgb(0 0 0 / .1), 0 1px 2px -1px rgb(0 0 0 / .1);--shadow-lg: 0 10px 15px -3px rgb(0 0 0 / .1), 0 4px 6px -4px rgb(0 0 0 / .1)}*{box-sizing:border-box;margin:0;padding:0}body{font-family:Segoe UI,Tahoma,Geneva,Verdana,sans-serif;background:linear-gradient(135deg,#667eea,#764ba2);min-height:100vh;padding:20px;color:var(--gray-800)}.auth-container{display:flex;justify-content:center;align-items:center;min-height:calc(100vh - 40px)}.auth-card{background:var(--white);border-radius:16px;padding:40px;box-shadow:var(--shadow-lg);width:100%;max-width:400px;text-align:center}.auth-card h1{font-size:2.5rem;font-weight:700;margin-bottom:30px;background:linear-gradient(135deg,var(--primary-color) 0%,var(--primary-hover) 100%);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}.auth-tabs{display:flex;margin-bottom:30px;border-radius:8px;overflow:hidden;border:1px solid var(--gray-200)}.auth-tab{flex:1;padding:12px 20px;background:var(--gray-50);border:none;cursor:pointer;font-weight:500;transition:all .2s ease;color:var(--gray-600)}.auth-tab.active{background:var(--primary-color);color:var(--white)}.auth-tab:hover:not(.active){background:var(--gray-100)}.auth-form{text-align:left}.auth-btn{width:100%;background:var(--primary-color);color:var(--white);border:none;padding:14px;border-radius:8px;font-size:1.1rem;font-weight:600;cursor:pointer;transition:all .2s ease;margin-top:10px}.auth-btn:hover{background:var(--primary-hover);transform:translateY(-1px);box-shadow:var(--shadow-lg)}.expense-tracker{max-width:800px;margin:0 auto;background:var(--white);border-radius:16px;box-shadow:var(--shadow-lg);overflow:hidden}.header{background:linear-gradient(135deg,var(--primary-color) 0%,var(--primary-hover) 100%);color:var(--white);padding:30px}.header-content{display:flex;justify-content:space-between;align-items:center;margin-bottom:20px}.header h1{font-size:2.5rem;font-weight:700}.user-info{display:flex;align-items:center;gap:15px;font-size:.9rem}.logout-btn{background:#fff3;color:var(--white);border:1px solid rgba(255,255,255,.3);padding:8px 16px;border-radius:6px;cursor:pointer;font-size:.875rem;transition:all .2s ease}.logout-btn:hover{background:#ffffff4d;transform:translateY(-1px)}.summary{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:20px}.summary-item{background:#ffffff1a;padding:15px;border-radius:8px;-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px)}.summary-label{font-size:.875rem;opacity:.9;margin-bottom:5px}.summary-value{font-size:1.5rem;font-weight:700}.expense-form{padding:30px;background:var(--gray-50);border-bottom:1px solid var(--gray-200)}.form-group{margin-bottom:20px}.form-group label{display:block;font-weight:600;margin-bottom:8px;color:var(--gray-700)}.form-group input,.form-group select{width:100%;padding:12px 16px;border:2px solid var(--gray-200);border-radius:8px;font-size:1rem;transition:all .2s ease;background:var(--white)}.form-group input:focus,.form-group select:focus{outline:none;border-color:var(--primary-color);box-shadow:0 0 0 3px #4f46e51a}.add-btn{width:100%;background:var(--success-color);color:var(--white);border:none;padding:14px;border-radius:8px;font-size:1.1rem;font-weight:600;cursor:pointer;transition:all .2s ease}.add-btn:hover{background:#059669;transform:translateY(-1px);box-shadow:var(--shadow-lg)}.filters{padding:20px 30px;background:var(--white);border-bottom:1px solid var(--gray-200);display:flex;gap:15px;align-items:center}.filters select{padding:8px 12px;border:1px solid var(--gray-300);border-radius:6px;font-size:.875rem}.refresh-btn{background:var(--primary-color);color:var(--white);border:none;padding:8px 16px;border-radius:6px;font-size:.875rem;font-weight:500;cursor:pointer;transition:all .2s ease;margin-left:auto}.refresh-btn:hover{background:var(--primary-hover)}.expenses-list{max-height:500px;overflow-y:auto;padding:20px 30px 30px}.expense-item{display:flex;align-items:center;gap:15px;padding:16px 0;border-bottom:1px solid var(--gray-100);transition:all .2s ease}.expense-item:hover{background:var(--gray-50);margin:0 -20px;padding-left:20px;padding-right:20px;border-radius:8px}.expense-item:last-child{border-bottom:none}.expense-info{flex:1}.expense-description{font-weight:600;font-size:1.1rem;color:var(--gray-800);margin-bottom:4px}.expense-meta{display:flex;gap:15px;font-size:.875rem;color:var(--gray-500)}.expense-category{background:var(--gray-100);padding:2px 8px;border-radius:12px;font-size:.75rem;font-weight:500}.expense-amount{font-size:1.25rem;font-weight:700;color:var(--primary-color);min-width:100px;text-align:right}.delete-btn{background:none;border:none;cursor:pointer;padding:8px;border-radius:6px;transition:all .2s ease;opacity:.6}.delete-btn:hover{opacity:1;background:var(--gray-100);transform:scale(1.1)}.empty-state{text-align:center;padding:60px 20px;color:var(--gray-500)}.empty-state p{margin-bottom:10px;font-size:1.1rem}.empty-state p:last-child{font-size:1.5rem}.message{margin-top:15px;padding:10px;border-radius:6px;font-weight:500;text-align:center;transition:all .3s ease}.message.success{background:#d1fae5;color:#065f46;border:1px solid #a7f3d0}.message.error{background:#fee2e2;color:#991b1b;border:1px solid #fca5a5}@media (max-width: 768px){body{padding:10px}.auth-card{padding:30px 20px}.header h1{font-size:2rem}.header-content{flex-direction:column;gap:15px;align-items:flex-start}.user-info{align-self:flex-end}.summary{grid-template-columns:repeat(2,1fr)}.expense-form,.filters,.expenses-list{padding:20px}.filters{flex-direction:column;align-items:stretch}.refresh-btn{margin-left:0;margin-top:10px}.expense-item{flex-direction:column;align-items:flex-start;gap:10px}.expense-amount{align-self:flex-end;min-width:auto}.delete-btn{align-self:flex-end;position:absolute;margin-top:-10px}}.expenses-list::-webkit-scrollbar{width:6px}.expenses-list::-webkit-scrollbar-track{background:var(--gray-100);border-radius:3px}.expenses-list::-webkit-scrollbar-thumb{background:var(--gray-300);border-radius:3px}.expenses-list::-webkit-scrollbar-thumb:hover{background:var(--gray-400)}@keyframes slideIn{0%{opacity:0;transform:translateY(10px)}to{opacity:1;transform:translateY(0)}}.expense-item{animation:slideIn .3s ease}.loading{opacity:.7;pointer-events:none}.loading:after{content:"";position:absolute;top:50%;left:50%;width:20px;height:20px;margin:-10px 0 0 -10px;border:2px solid var(--gray-300);border-top:2px solid var(--primary-color);border-radius:50%;animation:spin 1s linear infinite}@keyframes spin{0%{transform:rotate(0)}to{transform:rotate(360deg)}}