.container {
            max-width: 960px;
            margin: auto;
        }

        h1, h2, h3, h4 {
            color: #1a202c;
            font-weight: bold;
            margin-top: 0;
            margin-bottom: 0;
        }
        
        h1 {
            font-size: 2.25rem;
            text-align: center;
            margin-bottom: 2rem;
        }

        h2 {
            font-size: 1.5rem;
            font-weight: 600;
            margin-bottom: 1rem;
            border-bottom: 1px solid #e2e8f0;
            padding-bottom: 0.5rem;
        }
        
        h3 {
            font-size: 1.125rem;
        }
        
        h4 {
            font-weight: 600;
            margin-top: 1rem;
            color: #2d3748;
        }

        p {
            margin-bottom: 1rem;
        }
        
        a {
            color: var(--main-color);
            text-decoration: none;
        }
        
        a:hover {
            color: var(--secondary-color);
            text-decoration: underline;
        }
        
        b,
        .bold-text {
          font-weight: bold;
        }
        
        i,
        .italic-text {
          font-style: italic;
        }
        
        ul, ol, dl{
          line-height: 1.5;
        }

        .numlist {
            list-style-type: decimal;
            list-style-position: inside;
        }

        .bulletlist {
            list-style-type: disc;
            list-style-position: inside;
        }


        /* Layout */
        .main-grid {
            display: grid;
            grid-template-columns: 1fr;
            gap: 2rem;
        }

        @media (min-width: 768px) {
            .main-grid {
                grid-template-columns: repeat(2, 1fr);
            }
        }
        
        .card-padded {
            padding: 1rem;
        }

        .grid-container {
            display: grid;
            grid-template-columns: 1fr;
            gap: 1.5rem;
        }
        
        .grid-container-2-col {
            grid-template-columns: repeat(2, 1fr);
        }

        @media (min-width: 768px) {
            .grid-container-2-col {
                grid-template-columns: repeat(2, 1fr);
            }
        }

        .grid-span-2 {
            grid-column: span 2 / span 2;
        }

        /* Form & Inputs */
        .input-group {
            margin-bottom: 1rem;
        }

        label {
            display: block;
            font-size: 0.875rem;
            font-weight: bold;
            color: #4a5568;
            margin-bottom: 0.25rem;
        }
        
        input[type="number"], input[type="text"], select {
            width: 100%;
            padding: 0.5rem 0.75rem;
            border: 1px solid #cbd5e0;
            border-radius: 0.375rem;
            box-shadow: inset 0 1px 2px 0 rgba(0,0,0,0.05);
            font-size: 1rem;
            font-family: 'Inter', sans-serif;
            background-color: #f9fafb;
        }

        select {
             font-size: 0.875rem;
             border-radius: 0.5rem;
             padding: 0.625rem 0.75rem;
        }
        
        input:focus, select:focus {
            outline: none;
            border-color: var(--main-color);
            box-shadow: 0 0 0 3px rgba(26, 72, 238, 0.4);
        }

        /* Buttons */
        .button-container {
            display: flex;
            gap: 1rem;
            margin-top: 1.5rem;
        }
        
        .button {
            width: 100%;
            font-weight: bold;
            padding: 0.75rem 1rem;
            border: none;
            border-radius: 0.5rem;
            box-shadow: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -1px rgba(0,0,0,0.06);
            transition: background-color 0.3s, transform 0.3s;
            cursor: pointer;
            font-size: 1rem;
            color: var(--color-white);
        }
        
        .button:hover {
            transform: scale(1.05);
        }
        
        #calculateBtn {
            background-color: var(--main-color);
            padding: 0.75rem 2rem;
        }

        #calculateBtn:hover {
            background-color: var(--secondary-color);
        }

        .removeTierBtn {
            background-color: var(--color-error-dark);
            color: var(--color-white);
            font-weight: bold;
            padding: 0.25rem 0.5rem;
            font-size: 0.875rem;
            border: none;
            border-radius: 0.25rem;
            cursor: pointer;
        }
        
        .removeTierBtn:hover {
            background-color: var(--color-error-dark);
        }
        
        .instruction-box {
            background-color: #ebf8ff;
            border: 1px solid #bee3f8;
            border-radius: 0.5rem;
            padding: 1rem;
            margin-bottom: 2rem;
            font-size: 0.875rem;
            color: #2a4365;
        }

        .instruction-box ol, .instruction-box ul {
            margin-left: 1.5rem;
        }
        
        /* Results & Messages */
        .result-card {
            transition: all 0.3s ease-in-out;
            opacity: 0;
            transform: translateY(20px);
            max-height: 0;
            overflow: hidden;
        }
        .result-card.show {
            opacity: 1;
            transform: translateY(0);
            max-height: 1500px; /* Large enough to not clip content */
        }
        
        .hidden {
            display: none;
        }

        .result-amount {
            font-family: monospace;
            font-size: 1.125rem;
        }

        .result-message-pos {
            color: var(--color-green-dark);
        }

        .result-message-neg {
            color: var(--color-error-dark);
        }
        
        .error-message {
            text-align: center;
            color: var(--color-error-dark);
            font-weight: bold;
            background-color: #fcebeb;
            border: 1px solid var(--color-error-dark);
            padding: 1rem;
            border-radius: 0.5rem;
            margin-top: 1rem;
        }
        
        .results-header {
            text-align: center;
            font-size: 1.5rem;
            margin-bottom: 1.5rem;
        }
        
        .summary-box {
            background-color: #f9fafb;
            border-radius: 0.5rem;
            padding: 1rem;
            max-width: 40rem;
            margin: auto;
            color: #4a5568;
            font-size: 0.875rem;
        }
        
        .summary-row {
            display: flex;
            justify-content: space-between;
        }
        
        .summary-row.padded {
            padding-top: 0.5rem;
        }
        
        .summary-row.bold {
            font-weight: bold;
        }
        
        .summary-value-normal {
            font-weight: 500;
            color: #2d3748;
        }

        .summary-value-bold {
             font-weight: 600;
             color: #1a202c;
        }
        
        .summary-value-credit {
            font-weight: 500;
            color: var(--color-error-dark);
        }

        .summary-value-payments {
            font-weight: 500;
            color:var(--color-green-dark);
        }
        
        .summary-divider {
            margin-top: 0.25rem;
            margin-bottom: 0.25rem;
            border-color: #e2e8f0;
        }
        
        .breakdown-box {
            max-width: 40rem;
            margin: auto;
        }
        
        .breakdown-row {
            display: flex;
            justify-content: space-between;
            align-items: center;
            font-size: 0.875rem;
            padding: 0.5rem;
            border-radius: 0.375rem;
            background-color: #f9fafb;
        }
        
        .breakdown-rate {
            font-weight: 600;
            color: #2d3748;
        }
        
        .breakdown-value {
            font-weight: 600;
            color: #2d3748;
        }
        
        .disclaimer {
            text-align: center;
            margin-top: 1.5rem;
            font-size: 0.75rem;
            color: #6b7280;
        }
        
        .tax-card {
            padding: 1.5rem;
            border-radius: 0.75rem;
        }
        
        .tax-card h3 {
            font-size: 0.875rem;
            font-weight: 600;
            text-transform: uppercase;
        }
        
        .tax-card-refund {
            background-color: #ecfdf5;
        }
        
        .tax-card-refund h3 {
            color: var(--color-green-dark);;
        }

        .tax-card-refund p {
            color: var(--color-green-dark);
        }
        
        .tax-card-due {
            background-color: #eff6ff;
        }
        
        .tax-card-due h3 {
            color: #1e40af;
        }

        .tax-card-due p {
            color: #1e3a8a;
        }
        
        .marginal-rate-card {
            background-color: #ecfdf5;
        }
        
        .marginal-rate-card h3 {
           color: var(--color-green-dark);
        }
        
        .marginal-rate-card p {
            color: var(--color-green-dark);
        }
        
        .effective-rate-card {
            background-color: #eef2ff;
        }
        
        .effective-rate-card h3 {
            color: #3730a3;
        }
        
        .effective-rate-card p {
            color: #312e81;
        }
        
        .penalty-section {
            margin-top: 2rem;
            max-width: 42rem;
            margin-left: auto;
            margin-right: auto;
            background-color: #fffbeb;
            border: 1px solid #fde68a;
            border-radius: 0.5rem;
            padding: 1rem;
            font-size: 0.875rem;
            color: #78350f;
        }