:root {
    --primary-color: #800020; /* Deep burgundy - royal and prestigious */
    --secondary-color: #5D3A1A; /* Rich brown */
    --accent-color: #D4AF37; /* Classic gold */
    --text-light: #FFFFFF;
    --text-dark: #2C1810; /* Dark chocolate */
    --background-light: #FDF8F3; /* Warm ivory */
    --border-color: #E8D4C1; /* Light beige */
    --card-background: #F5ECE4; /* Soft ivory */
    --shadow-light: rgba(128, 0, 32, 0.05);
    --shadow-medium: rgba(128, 0, 32, 0.1);
    --shadow-strong: rgba(128, 0, 32, 0.15);
}

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

        body {
            font-family: 'Open Sans', sans-serif;
            line-height: 1.6;
            color: var(--text-dark);
            background-color: var(--grey-background);
            -webkit-font-smoothing: antialiased;
            -moz-osx-font-smoothing: grayscale;
        }

        .container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 20px;
        }

        a {
            text-decoration: none;
            color: var(--primary-color);
            transition: color 0.3s ease;
        }

        a:hover {
            color: var(--accent-color);
        }
        
        /* ------------------------------------------------------------------------- */
        /* 2. Header and Navigation  */
        /* ------------------------------------------------------------------------- */

        .navbar-top-logo {
            width: 100%;
            display: flex;
            justify-content: center;
            align-items: center;
            padding: 0 40px;
            max-width: 1200px;
            margin: 0 auto;
            z-index: 10;
        }
        .logo img {
            height: 80px;
            filter: drop-shadow(0 2px 5px rgba(0,0,0,0.2));
            /* Placeholder path for image: src="./pics/mathlogo.jpg" */
        }
        
        /* MODIFIED: Header to use abulogo.jpg as a background image with a dark overlay for text contrast */
        .page-header-section {
            color: var(--text-light);
            text-align: center;
            position: relative;
            padding: 20px 0 40px; 
            min-height: 250px; /* Ensure sufficient height */
            background-image: 
                linear-gradient(rgba(20, 24, 19, 0.808), rgba(4, 11, 19, 0.9)), 
                url('./pics/8084.jpg');
            background-size: cover;
            background-position: center center;
            background-repeat: no-repeat;
            display: flex;
            flex-direction: column;
            justify-content: center;
            align-items: center;
        }

        .page-title-content {
            padding-top: 20px;
            padding-bottom: 20px;
            z-index: 5;
            position: relative; /* Ensure title is on top of the background */
        }

        .page-title-content h1 {
            font-family: 'Montserrat', sans-serif;
            font-size: 3em;
            margin-bottom: 5px;
            line-height: 1.1;
            text-shadow: 2px 2px 5px rgba(0,0,0,0.5); /* Stronger shadow for readability */
        }

        .page-title-content h2 {
            font-family: 'Open Sans', sans-serif;
            font-size: 1.2em;
            font-weight: 400;
            opacity: 0.9;
            text-shadow: 1px 1px 3px rgba(0,0,0,0.5);
        }

        /* NEW NAVIGATION SECTION STYLES */
        .main-nav-container {
            background-color: var(--secondary-color);
            padding: 15px 0;
            box-shadow: 0 2px 10px rgba(0,0,0,0.1);
            position: sticky;
            top: 0;
            z-index: 100;
        }

        .main-nav {
            display: flex;
            justify-content: center;
            gap: 30px;
            flex-wrap: wrap;
            width: 100%;
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 10px;
            list-style: none;
        }

        .main-nav li a {
            color: var(--text-light);
            font-weight: 600;
            padding: 5px 0;
            transition: all 0.3s ease;
            text-transform: uppercase;
            white-space: nowrap;
        }

        .main-nav li a:hover,
        .main-nav li a.active {
            color: var(--accent-color);
            border-bottom: 2px solid var(--accent-color);
        }


        /* ------------------------------------------------------------------------- */
        /* 3. GPA Calculator Specific Styles */
        /* ------------------------------------------------------------------------- */

        .gpa-tool-section {
            padding: 40px 0 60px;
            background-color: var(--text-light);
        }

        .gpa-container {
            width: 100%;
            display: grid;
            grid-template-columns: 1fr; 
            gap: 30px;
        }

        .gpa-card {
            background-color: var(--border-color);
            padding: 30px;
            border-radius: 10px;
            box-shadow: 0 5px 15px var(--shadow-medium);
            transition: transform 0.3s ease, box-shadow 0.3s ease;
        }

        .gpa-card:hover {
            transform: translateY(-2px);
            box-shadow: 0 8px 20px var(--shadow-strong);
        }

        .gpa-card h2 {
            font-family: 'Montserrat', sans-serif;
            font-size: 1.6em;
            color: var(--primary-color);
            margin-bottom: 20px;
            border-bottom: 2px solid var(--accent-color);
            padding-bottom: 10px;
            font-weight: 700;
        }

        /* Input Rows */
        #courseInputs {
            display: flex;
            flex-direction: column;
            gap: 15px;
        }
        
        .course-row {
            display: flex;
            flex-wrap: wrap;
            gap: 10px;
            align-items: center;
            padding: 10px;
            border: 1px solid var(--light-blue-bg);
            border-radius: 6px;
            background-color: #fcfcfc;
            transition: border-color 0.3s, background-color 0.3s;
        }

        .course-row.invalid {
            border-color: #D4AF37; /* Red border for error */
            background-color: #fdd;
            box-shadow: 0 0 5px rgba(217, 83, 79, 0.5);
        }
        
        .course-row > input,
        .course-row > select {
            flex-grow: 1;
            min-width: 100px;
            padding: 10px;
            border: 1px solid var(--border-color);
            border-radius: 5px;
            font-size: 1em;
            color: var(--text-dark);
            transition: border-color 0.3s;
        }

        .course-row input:focus,
        .course-row select:focus {
            outline: none;
            border-color: var(--secondary-blue);
            box-shadow: 0 0 0 2px var(--light-blue-bg);
        }

        .course-name { flex-basis: 35%; }
        .course-grade { flex-basis: 25%; }
        .course-credits { flex-basis: 15%; }
        .remove-btn { flex-basis: 15%; }

        /* Buttons */
        .action-buttons {
            margin-top: 25px;
            display: flex;
            gap: 15px;
            flex-wrap: wrap;
        }

        .btn {
            padding: 12px 20px;
            border-radius: 5px;
            font-weight: 700;
            transition: background-color 0.3s ease, transform 0.2s ease, box-shadow 0.3s ease;
            border: none;
            cursor: pointer;
            text-transform: uppercase;
            flex-grow: 1;
            font-family: 'Montserrat', sans-serif;
            letter-spacing: 0.5px;
        }

        .btn-add {
            background-color: #155724;
            color: var(--text-light);
            box-shadow: 0 4px 10px rgba(0,0,0,0.1);
        }

        .btn-add:hover {
            background-color: #155724;
            transform: translateY(-2px);
        }

        .btn-calculate {
            background-color: var(--accent-color);
            color: var(--background-light);
            box-shadow: 0 4px 10px rgba(0,0,0,0.1);
        }

        .btn-calculate:hover {
            background-color: #E6C229;
            transform: translateY(-2px);
        }

        .remove-btn {
            background-color: #800020; /* Red */
            color: var(--text-light);
            font-weight: 500;
            padding: 10px 5px;
            min-width: 0;
            flex-basis: auto;
            font-size: 0.85em;
            text-transform: none;
        }

        .remove-btn:hover {
            background-color: #C9302C;
        }


        /* Results Summary */
        .results-summary {
            position: sticky;
            top: 100px;
            height: fit-content;
        }
        
        .results-summary .gpa-card {
            background-color: var(--border-color); 
            border: 2px solid var(--primary-blue);
            text-align: center;
        }

        .result-item {
            display: flex;
            flex-direction: column;
            align-items: center;
            padding: 15px 0;
            border-bottom: 1px dashed var(--border-color);
        }

        .result-item:last-of-type {
            border-bottom: none;
        }

        .result-label {
            font-size: 1em;
            color: var(--secondary-blue);
            font-weight: 600;
            margin-bottom: 5px;
            text-transform: uppercase;
        }

        #gpaResult {
            font-family: 'Montserrat', sans-serif;
            font-size: 4em;
            font-weight: 800;
            color: var(--primary-blue);
            line-height: 1;
        }

        #totalCredits {
            font-size: 2em;
            font-weight: 700;
            color: var(--secondary-blue);
            line-height: 1;
        }

        /* Message Box */
        #messageBox {
            margin-top: 20px;
            padding: 15px;
            border-radius: 6px;
            text-align: center;
            font-weight: 600;
            font-size: 0.95em;
        }

        .msg-error {
            background-color: #f8d7da;
            color: #721c24;
            border: 1px solid #f5c6cb;
        }
        .msg-success {
            background-color: #d4edda;
            color: #155724;
            border: 1px solid #c3e6cb;
        }

        .hidden {
            display: none;
        }

        /* ------------------------------------------------------------------------- */
        /* 4. Footer & President's Corner & Responsiveness */
        /* ------------------------------------------------------------------------- */

        footer {
            background-color: var(--secondary-color);
            color: var(--text-light);
            padding: 25px 0;
            text-align: center;
            font-size: 0.9em;
        }


        @media (min-width: 768px) {
            .gpa-container {
                grid-template-columns: 2fr 1fr; 
            }
            .course-name { width: 40%; }
            .course-grade { width: 25%; }
            .course-credits { width: 15%; }
            .remove-btn { width: 15%; }
            .action-buttons {
                flex-wrap: nowrap;
            }
            .page-title-content h1 {
                font-size: 3.5em;
            }
        }

        @media (max-width: 768px) {
            .main-nav {
                gap: 15px;
                padding: 0 5px;
                justify-content: space-around;
            }
            .main-nav li a {
                font-size: 0.9em;
            }
            .page-title-content h1 {
                font-size: 2.5em;
            }
        }

        @media (max-width: 500px) {
            .course-row {
                flex-direction: column;
                align-items: stretch;
            }

            .course-row > input,
            .course-row > select,
            .course-row > button {
                width: 100%;
                min-width: auto;
                flex-basis: auto;
            }
            
            .remove-btn {
                padding: 8px;
            }
            .action-buttons {
                flex-direction: column;
            }
        }