/* For hiding elements accessibly */
        .visually-hidden {
            border: 0;
            clip: rect(0 0 0 0);
            height: 1px;
            margin: -1px;
            overflow: hidden;
            padding: 0;
            position: absolute;
            width: 1px;
        }

        /* Layout containers */
        /* .articlecontainer is defined in your site's CSS */

        .card {
            background-color: var(--color-white);
            border-radius: 1rem;
            box-shadow: 0 10px 15px -3px var(--secondary-color), 0 4px 6px -2px var(--secondary-color);
            overflow: hidden;
            margin-top: 2rem;
            margin-bottom: 2rem;
        }
        .calculator-header {
            background-color: var(--color-white);
            padding: 1.5rem 2rem;
            border-bottom: 1px solid var(--border-color);
        }
        .calculator-header h1 {
            color: #1f2937;
            text-align: center;
            font-size: 1.75rem;
            font-weight: bold;
            margin: 0 0 0.5rem 0;
        }
        .calculator-header p {
            color: var(--color-gray);
            text-align: center;
            margin: 0;
        }
        .card>.grid-container {
            display: grid;
            grid-template-columns: 1fr;
            gap: 2rem;
            padding: 1.5rem;
        }
        @media (min-width: 1024px) {
            .card>.grid-container {
                grid-template-columns: repeat(2, 1fr);
                padding: 2rem;
            }
             .calculator-header h1 {
                font-size: 2rem;
            }
        }
        
        @media (max-width: 480px) {
            .calculator-header h1 {
                font-size: 1.5rem;
            }
        }
/* Input and form styling */
        .input-section > div {
            margin-bottom: 1.5rem;
        }
        label {
            display: block;
            font-size: 0.875rem;
            font-weight: 500;
            color: var(--color-gray);
            margin-bottom: 0.25rem;
        }
        input[type="date"] {
            width: 100%;
            padding: 0.5rem 1rem;
            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;
            transition: border-color 0.3s, box-shadow 0.3s;
        }
        input:focus {
            outline: none;
            border-color: var(--main-color);
            box-shadow: 0 0 0 3px rgba(26, 72, 238, 0.4);
        }
        .input-description {
            font-size: 0.8rem;
            color: var(--color-gray);
            margin-top: 0.25rem;
        }
        
        /* Button styling */
        .button-container {
            display: flex;
            gap: 1rem;
            padding-top: 1rem;
        }
        .btn {
            width: 100%;
            background-color: var(--main-color);
            color: var(--color-white);
            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: all 0.3s;
            cursor: pointer;
            font-size: 1rem;
        }
        .btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 7px 10px -3px rgba(0,0,0,0.15), 0 4px 6px -2px rgba(0,0,0,0.1);
        }
        .btn:focus {
            outline: none;
            box-shadow: 0 0 0 3px rgba(26, 72, 238, 0.4);
        }
        .btn-primary {
            background-color: var(--main-color);
        }
        .btn-primary:hover {
             background-color: var(--secondary-color);
        }
        .btn-secondary {
            background-color: var(--color-gray);
        }
        .btn-secondary:hover {
            background-color: #374151; /* Darker gray */
        }

        /* Instructions and Results styling */
        .instructions-box {
            background-color: var(--main-background);
            border: 1px solid var(--secondary-color);
            color: #1e40af;
            padding: 1rem;
            border-radius: 0.5rem;
            margin-bottom: 1.5rem;
        }
        .instructions-box h3 {
            font-weight: bold;
            font-size: 1.125rem;
            margin: 0 0 0.5rem 0;
        }
        .instructions-box ul {
            list-style-type: disc;
            list-style-position: inside;
            padding-left: 1rem;
            margin: 0;
        }
        .results-container {
            background-color: var(--secondary-background);
            padding: 1.5rem;
            border-radius: 0.5rem;
            border: 1px solid var(--border-color);
        }
        .results-container h2 {
            font-size: 1.25rem;
            font-weight: bold;
            color: #1f2937;
            margin: 0 0 1rem 0;
            text-align: center;
        }
        .results-summary {
            text-align: center;
            margin-bottom: 1.5rem;
            animation: fadeIn 0.5s ease-in-out;
        }
        .results-summary .years {
            font-size: 2.5rem;
            font-weight: bold;
            color: var(--main-color);
        }
         .results-summary .details {
            font-size: 1.25rem;
            color: var(--color-gray);
        }

        .results-item {
            display: flex;
            justify-content: space-between;
            padding: 0.75rem;
            background-color: #e5e7eb;
            border-radius: 0.5rem;
            margin-bottom: 0.75rem;
            flex-wrap: wrap;
            animation: fadeIn 0.5s ease-in-out;
        }
        .results-item span {
            word-break: break-word;
        }
        .results-item:last-child {
            margin-bottom: 0;
        }
        .results-item span:first-child {
            font-weight: 500;
            color: var(--color-gray);
            margin-right: 0.5rem;
        }
        .results-item span:last-child {
            font-weight: 600;
            color: #1f2937;
        }

        .birthday-countdown {
            margin-top: 1.5rem;
            padding-top: 1.5rem;
            border-top: 1px solid var(--border-color);
            text-align: center;
            animation: fadeIn 0.5s ease-in-out 0.2s;
            animation-fill-mode: both;
        }
        .birthday-countdown p {
             font-size: 1.1rem;
             font-weight: 500;
             color: #1f2937;
        }
        
        .error-message {
            text-align: center;
            color: var(--color-error-dark);
            font-weight: bold;
            padding: 1rem;
            background-color: #fee2e2;
            border: 1px solid #fecaca;
            border-radius: 0.5rem;
        }
        .ad-container {
            width: 100%;
            margin: 2rem auto;
            text-align: center;
            min-height: 90px;
        }
        /* SEO Content Styling */
        .seo-content {
            padding: 1.5rem 2rem;
        }
        .seo-content h2 {
            font-size: 1.5rem;
            font-weight: bold;
            margin-top: 0;
            margin-bottom: 1rem;
            padding-bottom: 0.5rem;
            border-bottom: 2px solid var(--border-color);
        }
         .seo-content h3 {
            font-size: 1.25rem;
            font-weight: bold;
            margin-top: 1.5rem;
            margin-bottom: 0.5rem;
        }
        .seo-content p, .seo-content ul {
            margin-bottom: 1rem;
        }
        .seo-content ul {
             list-style-position: inside;
        }
        @keyframes fadeIn {
            from {
                opacity: 0;
                transform: translateY(10px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }
        @media (max-width: 380px) {
            .button-container {
                flex-direction: column;
            }
        }