/* --- Base Styles & System Fonts --- */
        :root {
            --bg-color: #f3f4f6;
            --card-bg-color: #ffffff;
            --text-color: #1f2937;
            --text-muted-color: #6b7280;
            --border-color: #d1d5db;
            --input-bg-color: #f9fafb;
            --output-bg-color: #f3f4f6;
            --output-border-color: #e5e7eb;
            --primary-color: #2563eb;
            --primary-hover-color: #1d4ed8;
            --secondary-color: #9ca3af;
            --secondary-hover-color: #6b7280;
            --button-text-color: #ffffff;
            --focus-ring-color: rgba(59, 130, 246, 0.5);
            --shadow-color: rgba(0, 0, 0, 0.1);
            --header-footer-bg: #ffffff;
        }

        body {
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
            background-color: var(--bg-color);
            color: var(--text-color);
            display: flex;
            flex-direction: column; /* Stack header, main, footer */
            min-height: 100vh;
            margin: 0;
            box-sizing: border-box;
        }

        /* --- Header --- */
        .page-header {
            background-color: var(--header-footer-bg);
            padding: 1rem 2rem;
            box-shadow: 0 2px 4px var(--shadow-color);
            width: 100%;
            box-sizing: border-box;
            z-index: 10;
        }
        .header-content {
            display: flex;
            justify-content: space-between;
            align-items: center;
            flex-wrap: wrap; /* Allow wrapping on small screens */
            max-width: 1200px;
            margin: 0 auto;
        }
        .logo {
            font-size: 1.5rem;
            font-weight: 700;
            color: var(--primary-color);
        }
        .main-nav ul {
            margin: 0;
            padding: 0;
            list-style: none;
            display: flex;
            flex-wrap: wrap; /* Allow nav items to wrap */
            gap: 1.5rem;
        }
        .main-nav a {
            text-decoration: none;
            color: var(--text-muted-color);
            font-weight: 500;
            transition: color 0.2s;
        }
        .main-nav a:hover {
            color: var(--primary-color);
        }
        
        /* --- Main Content Area --- */
        main {
            flex-grow: 1;
            display: flex;
            flex-direction: column; /* Stack articles and tool */
            align-items: center;
            justify-content: center;
            padding: 2rem 1rem;
            width: 100%;
            box-sizing: border-box;
        }

        /* --- Tool Container --- */
        .tool-container {
            width: 100%;
            max-width: 42rem;
            background-color: var(--card-bg-color);
            border-radius: 1rem;
            box-shadow: 0 20px 25px -5px var(--shadow-color), 0 8px 10px -6px var(--shadow-color);
            padding: 2rem;
            margin: 2rem 0;
            box-sizing: border-box;
        }

        /* --- Editable Content Article --- */
        .content-article {
            width: 100%;
            max-width: 42rem;
            background-color: var(--card-bg-color);
            border-radius: 1rem;
            box-shadow: 0 10px 15px -3px var(--shadow-color), 0 4px 6px -4px var(--shadow-color);
            padding: 2rem;
            box-sizing: border-box;
        }
        .content-article h2 {
            font-size: 1.875rem;
            font-weight: 600;
            margin-top: 0;
            border-bottom: 1px solid var(--border-color);
            padding-bottom: 0.5rem;
            margin-bottom: 1rem;
        }
        .content-article p, .content-article li {
            line-height: 1.6;
        }
        .content-article p:last-child {
            margin-bottom: 0;
        }
        .content-article ol {
            padding-left: 1.5rem;
        }
        .content-article li {
            margin-bottom: 0.5rem;
        }

        /* --- Generator Header --- */
        .generator-header {
            text-align: center;
            margin-bottom: 2rem;
        }
        .generator-header h1 {
            font-size: 2.25rem;
            font-weight: 700;
            margin: 0;
        }
        .generator-header p {
            color: var(--text-muted-color);
            margin-top: 0.5rem;
        }

        /* --- Form Elements --- */
        .form-group {
            margin-bottom: 1.5rem;
        }
        label {
            display: block;
            font-size: 0.875rem;
            font-weight: 500;
            margin-bottom: 0.5rem;
        }
        textarea {
            width: 100%;
            padding: 1rem;
            background-color: var(--input-bg-color);
            border: 1px solid var(--border-color);
            border-radius: 0.5rem;
            transition: border-color 0.2s, box-shadow 0.2s;
            color: var(--text-color);
            font-size: 1rem;
            box-sizing: border-box;
            resize: vertical;
        }
        textarea:focus {
            outline: none;
            border-color: var(--primary-color);
            box-shadow: 0 0 0 2px var(--focus-ring-color);
        }
        textarea::placeholder {
            color: var(--text-muted-color);
        }

        /* --- Output Display --- */
        .output-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            flex-wrap: wrap; /* Allow wrapping */
            gap: 0.5rem; /* Add gap for wrapped items */
            margin-bottom: 0.5rem;
        }
        #outputText {
            display: block; /* <output> is inline by default */
            width: 100%;
            padding: 1rem;
            background-color: var(--output-bg-color);
            border-radius: 0.5rem;
            min-height: 100px;
            color: var(--text-color);
            white-space: pre-wrap;
            word-break: break-word;
            border: 1px solid var(--output-border-color);
            font-size: 1.125rem;
            box-sizing: border-box;
        }

        /* --- Buttons --- */
        .button-group {
            display: flex;
            gap: 0.5rem;
        }
        .button {
            padding: 0.5rem 1rem;
            border: none;
            border-radius: 0.5rem;
            cursor: pointer;
            transition: background-color 0.2s ease-in-out;
            font-size: 0.875rem;
            font-weight: 500;
            color: var(--button-text-color);
        }
        .button:focus {
            outline: none;
            box-shadow: 0 0 0 3px var(--focus-ring-color);
        }

        #copyButton {
            background-color: var(--primary-color);
        }
        #copyButton:hover {
            background-color: var(--primary-hover-color);
        }
        
        #clearButton {
            background-color: var(--secondary-color);
        }
        #clearButton:hover {
            background-color: var(--secondary-hover-color);
        }

        .copied-feedback {
            background-color: #22c55e !important;
        }
        
        /* --- Footer --- */
        .page-footer {
            background-color: var(--header-footer-bg);
            padding: 1.5rem 2rem;
            text-align: center;
            color: var(--text-muted-color);
            font-size: 0.875rem;
            border-top: 1px solid var(--border-color);
            width: 100%;
            box-sizing: border-box;
        }

        /* --- Responsive Styles --- */
        @media (max-width: 640px) {
            .header-content {
                flex-direction: column;
                gap: 1rem;
            }
            .main-nav ul {
                justify-content: center;
                gap: 1rem;
            }
            main {
                padding: 1rem;
            }
            .tool-container, .content-article {
                padding: 1.5rem;
                margin: 1rem 0;
            }
            .generator-header h1 {
                font-size: 1.75rem;
            }
            .content-article h2 {
                font-size: 1.5rem;
            }
            .output-header {
                flex-direction: column;
                align-items: flex-start;
                gap: 0.75rem;
            }
            .button-group {
                width: 100%;
                justify-content: flex-end;
            }
        }