:root {
    --bg-color: #0f172a;
    --panel-bg: rgba(30, 41, 59, 0.7);
    --panel-border: rgba(255, 255, 255, 0.1);
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --accent: #3b82f6;
    --accent-hover: #2563eb;
    --accent-glow: rgba(59, 130, 246, 0.5);
    --danger: #ef4444;
    --danger-hover: #dc2626;
    --success: #10b981;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    background-image: radial-gradient(circle at top right, rgba(59, 130, 246, 0.15), transparent 40%),
                      radial-gradient(circle at bottom left, rgba(16, 185, 129, 0.1), transparent 40%);
    color: var(--text-primary);
    min-height: 100vh;
    padding: 2rem;
    display: flex;
    justify-content: center;
}

.app-container {
    width: 100%;
    max-width: 1200px;
    display: flex;
    flex-direction: column;
    gap: 2rem;
    overflow-x: hidden;
}

header {
    text-align: center;
    padding: 1rem 0;
}

header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, #60a5fa, #34d399);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 0.5rem;
}

header p {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

main {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 2rem;
    align-items: start;
}

@media (max-width: 900px) {
    main {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    body {
        padding: 0.5rem;
    }
    
    header h1 {
        font-size: 1.8rem;
    }
    
    .panel {
        padding: 1.25rem;
        border-radius: 12px;
    }
    
    .dimensions-grid {
        grid-template-columns: 1fr !important; /* Forces stacking on mobile */
        gap: 0.75rem;
    }
    
    .table-actions {
        flex-direction: column !important;
        width: 100%;
    }
    
    .table-actions button {
        width: 100% !important;
    }
    
    th, td {
        padding: 0.75rem 0.5rem;
        font-size: 0.85rem;
    }
    
    .total-value {
        font-size: 1.2rem !important;
    }
}

.panel {
    background: var(--panel-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--panel-border);
    border-radius: 16px;
    padding: 2rem;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
    min-width: 0;
}

h2 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    font-weight: 600;
    border-bottom: 1px solid var(--panel-border);
    padding-bottom: 0.75rem;
}

.form-group {
    margin-bottom: 1.5rem;
}

label {
    display: block;
    margin-bottom: 0.5rem;
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-weight: 500;
}

select, input {
    width: 100%;
    background: rgba(15, 23, 42, 0.6);
    border: 1px solid var(--panel-border);
    color: var(--text-primary);
    padding: 0.75rem 1rem;
    border-radius: 8px;
    font-size: 1rem;
    font-family: inherit;
    transition: all 0.3s ease;
    outline: none;
}

select:focus, input:focus {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

.dimensions-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.calculation-preview {
    background: rgba(15, 23, 42, 0.4);
    border-radius: 8px;
    padding: 1rem;
    margin-bottom: 1.5rem;
    display: flex;
    justify-content: space-between;
    border: 1px dashed var(--panel-border);
}

.preview-item {
    display: flex;
    flex-direction: column;
}

.preview-label {
    font-size: 0.8rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.preview-value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--success);
}

.preview-unit {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-left: 0.2rem;
}

button {
    width: 100%;
    padding: 1rem;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

.btn-primary {
    background: var(--accent);
    color: white;
    box-shadow: 0 4px 14px var(--accent-glow);
}

.btn-primary:hover:not(:disabled) {
    background: var(--accent-hover);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px var(--accent-glow);
}

.btn-primary:disabled {
    background: #475569;
    box-shadow: none;
    cursor: not-allowed;
    opacity: 0.7;
}

.btn-danger {
    background: transparent;
    color: var(--danger);
    padding: 0.5rem;
    border-radius: 6px;
    border: 1px solid var(--danger);
}

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

/* Table Styles */
.table-container {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch; /* Smooth scrolling on iOS */
    border-radius: 8px;
    margin-bottom: 1rem;
    width: 100%;
    max-width: 100vw;
}

/* Custom Scrollbar for the table container */
.table-container::-webkit-scrollbar {
    height: 6px;
}
.table-container::-webkit-scrollbar-track {
    background: rgba(255, 255, 255, 0.05);
    border-radius: 4px;
}
.table-container::-webkit-scrollbar-thumb {
    background: var(--accent);
    border-radius: 4px;
}

table {
    width: 100%;
    border-collapse: collapse;
    text-align: left;
}

th, td {
    padding: 1rem;
    border-bottom: 1px solid var(--panel-border);
}

th {
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

tbody tr {
    transition: background-color 0.2s ease;
}

tbody tr:hover {
    background-color: rgba(255, 255, 255, 0.05);
}

tfoot td {
    border-top: 2px solid var(--panel-border);
    border-bottom: none;
    font-size: 1.2rem;
    padding-top: 1.5rem;
}

.total-label {
    text-align: right;
    font-weight: 600;
    color: var(--text-secondary);
}

.total-value {
    font-weight: 700;
    color: var(--success);
    font-size: 1.5rem !important;
}

.empty-state {
    text-align: center;
    padding: 3rem 1rem;
    color: var(--text-secondary);
}