*,*:before,*:after{box-sizing:border-box;margin:0;padding:0}:root{--bg: #f5f5f4;--surface: #ffffff;--border: #e5e7eb;--text: #111827;--muted: #6b7280;--primary: #16a34a;--primary-h: #15803d;--danger: #dc2626;--settle: #2563eb;--settle-h: #1d4ed8;--radius: 10px;--shadow: 0 1px 3px rgba(0,0,0,.08), 0 1px 2px rgba(0,0,0,.04)}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif;background:var(--bg);color:var(--text);font-size:15px;line-height:1.5}.app{max-width:820px;margin:0 auto;padding:0 16px 80px}.app-loading{display:flex;align-items:center;justify-content:center;height:100vh;color:var(--muted)}.app-header{display:flex;align-items:center;justify-content:space-between;padding:24px 0 20px}.header-actions{display:flex;align-items:center;gap:4px}.app-header h1{font-size:22px;font-weight:700;letter-spacing:-.3px}.balance-card{display:flex;align-items:center;justify-content:space-between;gap:16px;background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:20px 24px;margin-bottom:24px;box-shadow:var(--shadow)}.balance-card.settled{border-left:4px solid var(--primary)}.balance-card.outstanding{border-left:4px solid var(--settle)}.balance-card.skeleton{height:80px;background:var(--border);animation:pulse 1.2s ease infinite}.balance-info{display:flex;flex-direction:column;gap:2px}.balance-label{font-size:15px;font-weight:500}.balance-amount{font-size:28px;font-weight:700;color:var(--settle)}.expenses-section{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow);overflow:hidden}.settlements-section{margin-top:20px}.section-header{display:flex;align-items:center;justify-content:space-between;padding:16px 20px;border-bottom:1px solid var(--border)}.section-header h2{font-size:16px;font-weight:600}.expense-list-header,.expense-row{display:grid;grid-template-columns:80px 1fr 100px 90px 1fr 64px;gap:8px;align-items:center;padding:10px 20px;font-size:13.5px}.settlement-list-header,.settlement-row{grid-template-columns:80px 1fr 90px 1fr 32px}.expense-list-header{background:var(--bg);color:var(--muted);font-size:12px;font-weight:600;text-transform:uppercase;letter-spacing:.4px;border-bottom:1px solid var(--border)}.expense-row{border-bottom:1px solid var(--border)}.expense-row:last-child{border-bottom:none}.expense-row:hover{background:#fafafa}.exp-date{color:var(--muted);white-space:nowrap}.exp-desc{font-weight:500;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.exp-amount{font-weight:600;text-align:right;padding-right:8px}.exp-split{color:var(--muted);font-size:12.5px}.exp-actions{display:flex;align-items:center;gap:2px;justify-content:flex-end}.settle-amount{color:var(--settle)}.empty,.muted{padding:32px 20px;text-align:center;color:var(--muted)}.btn{display:inline-flex;align-items:center;gap:6px;padding:8px 16px;border-radius:7px;font-size:14px;font-weight:500;cursor:pointer;border:none;transition:background .15s;white-space:nowrap}.btn:disabled{opacity:.55;cursor:not-allowed}.btn-primary{background:var(--primary);color:#fff}.btn-primary:hover:not(:disabled){background:var(--primary-h)}.btn-secondary{background:var(--border);color:var(--text)}.btn-secondary:hover:not(:disabled){background:#d1d5db}.btn-settle{background:var(--settle);color:#fff}.btn-settle:hover{background:var(--settle-h)}.btn-icon{background:none;border:none;cursor:pointer;padding:4px 8px;border-radius:5px;color:var(--muted);font-size:14px;line-height:1;transition:background .15s,color .15s}.btn-icon:hover{background:var(--border);color:var(--text)}.btn-delete:hover{background:#fee2e2;color:var(--danger)}.btn-edit:hover{background:#e0f2fe;color:#0369a1}.btn-undo:hover{background:#fef3c7;color:#92400e}.btn-settings{font-size:18px;padding:4px 8px}.btn-group{display:flex;gap:0}.btn-toggle{flex:1;padding:8px 14px;background:var(--bg);border:1px solid var(--border);cursor:pointer;font-size:14px;font-weight:500;transition:background .12s,color .12s}.btn-toggle:first-child{border-radius:7px 0 0 7px}.btn-toggle:last-child{border-radius:0 7px 7px 0;border-left:none}.btn-toggle.active{background:var(--primary);color:#fff;border-color:var(--primary);z-index:1}.modal-backdrop{position:fixed;top:0;right:0;bottom:0;left:0;background:#0006;display:flex;align-items:center;justify-content:center;z-index:100;padding:16px}.modal{background:var(--surface);border-radius:var(--radius);box-shadow:0 20px 60px #0003;width:100%;max-width:480px;animation:slide-in .18s ease}.modal-header{display:flex;align-items:center;justify-content:space-between;padding:20px 24px 0}.modal-header h2{font-size:17px;font-weight:700}.form{padding:20px 24px 24px;display:flex;flex-direction:column;gap:16px}.field{display:flex;flex-direction:column;gap:5px}.field label{font-size:13px;font-weight:600;color:var(--muted)}.fields-row{display:grid;grid-template-columns:1fr 1fr;gap:12px}input,select{padding:9px 12px;border:1px solid var(--border);border-radius:7px;font-size:14px;outline:none;background:var(--surface);color:var(--text);transition:border-color .15s}input:focus,select:focus{border-color:var(--primary)}input[type=number]{font-variant-numeric:tabular-nums}.optional{font-weight:400;color:var(--muted)}.split-preview{font-size:13px;color:var(--muted);background:var(--bg);border-radius:6px;padding:8px 12px}.form-actions{display:flex;justify-content:flex-end;gap:10px;margin-top:4px}.settle-summary{padding:0 24px;color:var(--muted);font-size:14px;margin-top:16px}.settle-summary strong{color:var(--text)}.login-page{display:flex;align-items:center;justify-content:center;min-height:100vh;padding:16px}.login-card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow);width:100%;max-width:360px;padding:32px 32px 28px}.login-title{font-size:22px;font-weight:700;letter-spacing:-.3px;margin-bottom:24px}.error{color:var(--danger);font-size:13px}@keyframes pulse{0%,to{opacity:1}50%{opacity:.4}}@keyframes slide-in{0%{opacity:0;transform:translateY(-12px)}to{opacity:1;transform:translateY(0)}}@media(max-width:600px){.expense-list-header,.expense-row{grid-template-columns:70px 1fr 80px 28px}.exp-payer,.exp-split,.expense-list-header span:nth-child(3),.expense-list-header span:nth-child(5){display:none}.settlement-list-header,.settlement-row{grid-template-columns:70px 1fr 80px 28px}.settlement-row .exp-split{display:none}.settlement-list-header span:nth-child(4){display:none}.balance-amount{font-size:22px}.fields-row{grid-template-columns:1fr}}