* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

:root {
    --bg-color: #080b12;
    --card-bg: rgba(18, 25, 43, 0.65);
    --card-border: rgba(255, 255, 255, 0.08);
    --card-border-glow: rgba(59, 130, 246, 0.3);
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --accent: #3b82f6;
    --accent-hover: #2563eb;
    --success: #10b981;
    --success-hover: #059669;
    --warning: #f59e0b;
    --danger: #ef4444;
    --danger-hover: #dc2626;
    --gold: #fbbf24;
}

body {
    background-color: var(--bg-color);
    background-image: 
        radial-gradient(circle at 10% 20%, rgba(59, 130, 246, 0.08), transparent 30%),
        radial-gradient(circle at 90% 80%, rgba(251, 191, 36, 0.05), transparent 30%);
    background-attachment: fixed;
    color: var(--text-main);
    min-height: 100vh;
    padding: 2rem;
    overflow-x: hidden;
}

/* Glassmorphism Utilities */
.glass {
    background: var(--card-bg);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--card-border);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
}

/* Typography & Buttons */
.primary-btn {
    background: var(--accent);
    color: white;
    border: none;
    padding: 0.85rem 1.5rem;
    border-radius: 10px;
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    box-shadow: 0 4px 15px rgba(59, 130, 246, 0.3);
}

.primary-btn:hover {
    background: var(--accent-hover);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(59, 130, 246, 0.4);
}

.danger-btn {
    background: rgba(239, 68, 68, 0.1);
    color: var(--danger);
    border: 1px solid rgba(239, 68, 68, 0.3);
    padding: 0.85rem 1.5rem;
    border-radius: 10px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
}

.danger-btn:hover {
    background: var(--danger);
    color: white;
}

.icon-btn {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--card-border);
    color: var(--text-muted);
    width: 42px;
    height: 42px;
    border-radius: 10px;
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    transition: all 0.2s;
}

.icon-btn:hover {
    background: rgba(255, 255, 255, 0.1);
    color: var(--text-main);
}

.icon-btn.logout-btn:hover {
    background: rgba(239, 68, 68, 0.2);
    color: var(--danger);
    border-color: rgba(239, 68, 68, 0.5);
}

/* Overlays (Login & Modals) */
.overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    z-index: 1000;
    display: flex;
    justify-content: center;
    align-items: center;
    opacity: 1;
    transition: opacity 0.4s ease, visibility 0.4s;
}

.overlay.hidden {
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
}

.login-box, .modal-box {
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: 20px;
    padding: 2.5rem;
    width: 100%;
    max-width: 420px;
    text-align: center;
    box-shadow: 0 20px 50px rgba(0,0,0,0.5), inset 0 0 0 1px rgba(255,255,255,0.05);
    transform: translateY(0) scale(1);
    transition: transform 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.overlay.hidden .login-box, .overlay.hidden .modal-box {
    transform: translateY(30px) scale(0.95);
}

.modal-box {
    max-width: 500px;
    text-align: left;
    padding: 0;
    display: flex;
    flex-direction: column;
    max-height: 85vh;
}

.modal-header {
    padding: 1.5rem;
    border-bottom: 1px solid var(--card-border);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-content {
    padding: 1.5rem;
    overflow-y: auto;
    flex: 1;
}

.modal-footer {
    padding: 1.5rem;
    border-top: 1px solid var(--card-border);
    text-align: right;
}

.close-btn {
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
}
.close-btn:hover { color: var(--text-main); }

.logo-icon.large {
    width: 72px;
    height: 72px;
    font-size: 2.5rem;
    margin: 0 auto 1.5rem;
}

.login-box h2 { margin-bottom: 0.5rem; }
.login-box p { color: var(--text-muted); margin-bottom: 2rem; font-size: 0.9rem; }
.login-box .input-group { margin-bottom: 1.25rem; }
.login-box input {
    width: 100%;
    background: rgba(0, 0, 0, 0.4);
    border: 1px solid rgba(255, 255, 255, 0.1);
    color: #fff;
    padding: 1.2rem;
    border-radius: 12px;
    font-size: 1rem;
    transition: all 0.3s;
}
.login-box input:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 15px rgba(59, 130, 246, 0.3);
    background: rgba(0, 0, 0, 0.6);
}
.login-box .primary-btn { width: 100%; margin-top: 0.5rem; }

.auth-toggle {
    margin-top: 1.5rem;
    font-size: 0.9rem;
    color: var(--text-muted);
}
.auth-toggle a {
    color: var(--accent);
    text-decoration: none;
    font-weight: 600;
    margin-left: 0.5rem;
    transition: color 0.2s;
}
.auth-toggle a:hover {
    color: var(--accent-hover);
    text-decoration: underline;
}

/* Main Layout */
#appContainer {
    opacity: 1;
    transition: opacity 0.5s ease;
}
#appContainer.hidden {
    opacity: 0;
    visibility: hidden;
    height: 0;
    overflow: hidden;
    position: absolute;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
    background: var(--card-bg);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--card-border);
    border-radius: 16px;
    margin-bottom: 1.5rem;
    box-shadow: 0 10px 30px -10px rgba(0,0,0,0.5);
    position: sticky;
    top: 1rem;
    z-index: 100;
}

.header-right {
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

.profile-actions {
    display: flex;
    gap: 0.5rem;
    border-left: 1px solid var(--card-border);
    padding-left: 1.5rem;
}

.logo-container { display: flex; align-items: center; gap: 1rem; }
.logo-icon {
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, var(--gold), #d97706);
    border-radius: 12px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 1.5rem;
    font-weight: 800;
    color: #fff;
    box-shadow: 0 4px 15px rgba(251, 191, 36, 0.3);
}

.title h1 { font-size: 1.25rem; font-weight: 700; text-transform: uppercase; }
.title p { font-size: 0.85rem; color: var(--text-muted); }

.revenue-box { text-align: right; }
.revenue-box span { font-size: 0.8rem; color: var(--text-muted); }
.revenue-box h2 { font-size: 1.4rem; color: var(--success); font-weight: 700; }

.calculator-header {
    background: rgba(16, 185, 129, 0.05);
    border: 1px solid rgba(16, 185, 129, 0.2);
    padding: 1.5rem 2rem;
    border-radius: 16px;
    margin-bottom: 2rem;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.calc-top-row, .calc-bottom-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1.5rem;
}

.calc-bottom-row {
    padding-top: 1.5rem;
    border-top: 1px dashed rgba(16, 185, 129, 0.2);
}

.discount-box {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    align-items: flex-end;
}
.discount-box .input-wrapper { width: 150px; }
.discount-box input { text-align: center; }

.change-calc-box {
    display: flex;
    align-items: center;
    gap: 1.5rem;
    flex: 1;
}

.change-result {
    display: flex;
    flex-direction: column;
}
.change-result span { font-size: 0.85rem; color: var(--text-muted); }
.change-result strong { font-size: 1.5rem; }

.success-text { color: var(--success); }

.sell-btn {
    background: var(--success);
    box-shadow: 0 4px 15px rgba(16, 185, 129, 0.3);
}
.sell-btn:hover { background: var(--success-hover); box-shadow: 0 6px 20px rgba(16, 185, 129, 0.4); }

.grand-total-box span { display: block; font-size: 0.9rem; color: var(--text-main); font-weight: 500; }
.grand-total-box h2 { font-size: 2rem; font-weight: 800; color: #fff; text-shadow: 0 2px 10px rgba(0,0,0,0.5); }

/* Tabs */
.tabs {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
    overflow-x: auto;
    padding-bottom: 0.5rem;
}
.tabs::-webkit-scrollbar { height: 6px; }
.tabs::-webkit-scrollbar-track { background: rgba(0,0,0,0.2); border-radius: 3px; }
.tabs::-webkit-scrollbar-thumb { background: rgba(255,255,255,0.1); border-radius: 3px; }

.tab-btn {
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    color: var(--text-muted);
    padding: 1rem 1.5rem;
    border-radius: 12px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    white-space: nowrap;
}
.tab-btn:hover { background: rgba(255, 255, 255, 0.05); color: var(--text-main); }
.tab-btn.active {
    background: var(--accent);
    color: #fff;
    border-color: var(--accent);
    box-shadow: 0 4px 15px rgba(59, 130, 246, 0.4);
}

.category-section { display: none; animation: fadeIn 0.4s ease-out; }
.category-section.active { display: block; }

/* Grid & Cards */
.items-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 1.5rem;
}

.item-card {
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: 16px;
    padding: 1.5rem;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
    position: relative;
    overflow: hidden;
}

.item-card::before {
    content: '';
    position: absolute;
    top: 0; left: 0; width: 100%; height: 100%;
    background: linear-gradient(180deg, rgba(255,255,255,0.03) 0%, transparent 100%);
    pointer-events: none;
}

.item-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 25px -10px rgba(0,0,0,0.6);
    border-color: var(--card-border-glow);
}

.item-header { display: flex; justify-content: space-between; align-items: flex-start; z-index: 1; }
.item-name { font-size: 1.15rem; font-weight: 600; color: #fff; }
.item-desc { font-size: 0.8rem; color: var(--text-muted); margin-top: 0.25rem; }

.reset-btn {
    background: rgba(255,255,255,0.05);
    border: 1px solid transparent;
    border-radius: 6px;
    padding: 4px;
    color: var(--text-muted);
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    align-items: center;
}
.reset-btn:hover { color: var(--warning); background: rgba(245, 158, 11, 0.1); border-color: rgba(245, 158, 11, 0.3); }

.item-controls { display: flex; flex-direction: column; gap: 1rem; z-index: 1; }
.control-group { display: flex; flex-direction: column; gap: 0.5rem; }
.control-group label { font-size: 0.75rem; color: var(--text-muted); font-weight: 600; text-transform: uppercase; letter-spacing: 0.5px;}

.input-wrapper { 
    position: relative; 
    display: flex; 
    align-items: center; 
    border-radius: 10px;
    background: rgba(0, 0, 0, 0.2);
    border: 1px solid rgba(255, 255, 255, 0.08);
    transition: all 0.3s;
}
.input-wrapper:focus-within {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.15);
    background: rgba(0, 0, 0, 0.4);
}
.input-prefix, .input-suffix { 
    position: absolute; 
    color: var(--text-muted); 
    font-size: 0.9rem; 
    font-weight: 500;
    pointer-events: none; 
}
.input-prefix { left: 1rem; border-right: 1px solid rgba(255,255,255,0.1); padding-right: 0.75rem; }
.input-suffix { right: 1rem; border-left: 1px solid rgba(255,255,255,0.1); padding-left: 0.75rem; }

input[type="number"] {
    width: 100%;
    background: transparent;
    border: none;
    color: #fff;
    padding: 0.85rem 1rem;
    font-size: 1.05rem;
    font-weight: 600;
    outline: none;
    -moz-appearance: textfield; /* Firefox hide spinner */
}
input[type="number"]::-webkit-outer-spin-button,
input[type="number"]::-webkit-inner-spin-button {
    -webkit-appearance: none;
    margin: 0;
}
.price-input { padding-left: 3.5rem !important; }
.qty-input { padding-right: 4.5rem !important; }
.qty-input:not(:placeholder-shown) { color: var(--success); }

.item-footer {
    margin-top: auto;
    padding-top: 1rem;
    border-top: 1px dashed rgba(255,255,255,0.1);
    display: flex;
    justify-content: space-between;
    align-items: center;
    z-index: 1;
}
.total-label { font-size: 0.85rem; color: var(--text-muted); }
.item-total { font-size: 1.25rem; font-weight: 700; color: var(--success); }

/* History Items */
.history-item {
    padding: 1rem;
    border: 1px solid rgba(255,255,255,0.05);
    background: rgba(0,0,0,0.2);
    border-radius: 10px;
    margin-bottom: 0.75rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.history-item:last-child { margin-bottom: 0; }
.history-time { font-size: 0.85rem; color: var(--text-muted); }
.history-amount { font-weight: 700; color: var(--success); }
.empty-state { text-align: center; color: var(--text-muted); padding: 2rem 0; font-style: italic; }

/* Actions Bar */
.actions-bar { position: fixed; bottom: 2rem; right: 2rem; display: flex; gap: 1rem; z-index: 90; }
.action-btn {
    background: var(--card-bg); border: 1px solid var(--card-border); color: #fff;
    width: 56px; height: 56px; border-radius: 50%;
    display: flex; justify-content: center; align-items: center;
    cursor: pointer; box-shadow: 0 8px 20px rgba(0,0,0,0.4);
    transition: all 0.3s; backdrop-filter: blur(10px);
}
.action-btn:hover { transform: scale(1.1); background: var(--danger); border-color: var(--danger); }
.action-btn svg { width: 24px; height: 24px; fill: currentColor; }

/* Toast Notifications */
.toast-container {
    position: fixed; top: 2rem; right: 2rem; z-index: 2000;
    display: flex; flex-direction: column; gap: 1rem; pointer-events: none;
}
.toast {
    background: var(--card-bg); backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--card-border); border-left: 4px solid var(--accent);
    color: white; padding: 1rem 1.5rem; border-radius: 8px;
    box-shadow: 0 10px 25px rgba(0,0,0,0.5);
    transform: translateX(120%); transition: transform 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    display: flex; align-items: center; gap: 0.75rem;
}
.toast.show { transform: translateX(0); }
.toast.success { border-left-color: var(--success); }
.toast.error { border-left-color: var(--danger); }
.toast-icon { width: 20px; height: 20px; flex-shrink: 0; }

/* Search Bar */
.search-container {
    margin-bottom: 1.5rem;
}
.search-wrapper {
    position: relative;
    display: flex;
    align-items: center;
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: 12px;
    padding: 0.5rem 1rem;
    backdrop-filter: blur(10px);
    transition: all 0.3s;
}
.search-wrapper:focus-within {
    border-color: var(--accent);
    box-shadow: 0 0 15px rgba(59, 130, 246, 0.2);
}
.search-wrapper svg {
    color: var(--text-muted);
    margin-right: 1rem;
}
.search-wrapper input {
    flex: 1;
    background: transparent;
    border: none;
    color: #fff;
    padding: 0.75rem 0;
    font-size: 1.05rem;
    outline: none;
}

/* Quick Add Buttons */
.quick-add-group {
    display: flex;
    gap: 0.5rem;
    margin-top: 0.5rem;
}
.quick-add-btn {
    flex: 1;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    color: var(--text-muted);
    padding: 0.4rem;
    border-radius: 6px;
    font-size: 0.8rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
}
.quick-add-btn:hover {
    background: rgba(59, 130, 246, 0.2);
    border-color: rgba(59, 130, 246, 0.4);
    color: #fff;
}

/* Footer */
.app-footer {
    margin-top: 4rem;
    padding: 2rem;
    text-align: center;
    border-top: 1px dashed var(--card-border);
    background: rgba(0, 0, 0, 0.2);
    backdrop-filter: blur(10px);
    border-radius: 20px 20px 0 0;
}
.footer-content p {
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-bottom: 0.5rem;
}
.footer-content p.author {
    font-size: 0.8rem;
}
.footer-content p.author span {
    color: var(--accent);
    font-weight: 700;
}

/* Receipt Modal */
.receipt-box {
    background: #fff;
    color: #111;
    border-radius: 0;
    width: 380px;
    padding: 0;
    box-shadow: 0 10px 40px rgba(0,0,0,0.5);
    font-family: 'Courier New', Courier, monospace;
}
.receipt-content {
    padding: 2rem 2rem 1rem;
}
.receipt-header {
    text-align: center;
    border-bottom: 1px dashed #666;
    padding-bottom: 1rem;
    margin-bottom: 1rem;
}
.receipt-header h3 { font-size: 1.25rem; font-weight: 700; margin-bottom: 0.5rem; }
.receipt-header p { font-size: 0.85rem; color: #555; }
.receipt-table { width: 100%; border-collapse: collapse; margin-bottom: 1rem; }
.receipt-table th, .receipt-table td { padding: 0.25rem 0; font-size: 0.9rem; text-align: left; }
.receipt-table th { border-bottom: 1px dashed #ccc; padding-bottom: 0.5rem; }
.receipt-table .text-right { text-align: right; }
.receipt-totals { border-top: 1px dashed #666; padding-top: 1rem; margin-top: 1rem; }
.receipt-totals .row { display: flex; justify-content: space-between; margin-bottom: 0.25rem; font-size: 0.95rem;}
.receipt-totals .row.bold { font-weight: 700; font-size: 1.1rem; margin-top: 0.5rem; }
.receipt-footer { text-align: center; font-size: 0.8rem; margin-top: 2rem; color: #555; border-top: 1px dashed #ccc; padding-top: 1rem; }

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

@media print {
    body * { visibility: hidden; }
    #receiptModal, #receiptModal * { visibility: visible; }
    #receiptModal {
        position: absolute; left: 0; top: 0; background: none; box-shadow: none; align-items: flex-start;
    }
    .receipt-box { width: 100%; box-shadow: none; padding: 0; }
    .no-print { display: none !important; }
}

@media (max-width: 768px) {
    header { flex-direction: column; gap: 1rem; align-items: stretch; }
    .header-right { flex-direction: column; gap: 1rem; border-left: none; padding-left: 0; padding-top: 1rem; border-top: 1px solid var(--card-border); }
    
    .calc-top-row, .calc-bottom-row { flex-direction: column; gap: 1rem; }
    .change-calc-box { flex-direction: column; width: 100%; }
    .change-calc-box .input-wrapper { width: 100%; }
    .sell-btn { width: 100%; }
    
    .items-grid { grid-template-columns: 1fr; }
}