:root {
            --academic-blue: #0f2c59;
            --academic-light-bg: #f8f9fa;
            --academic-card-bg: #ffffff;
            --academic-text: #212529;
            --academic-muted: #6c757d;
            --academic-border: #ced4da;
            --academic-alert: #dc3545;
            --academic-success: #198754;
            --academic-focus: #0d6efd;
        }

        body { 
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif; 
            background-color: var(--academic-light-bg); 
            color: var(--academic-text); 
            padding: 20px 10px; 
            display: flex; 
            justify-content: center; 
            align-items: center;
            min-height: 100vh;
            margin: 0;
            box-sizing: border-box;
        }

        .card { 
            background: var(--academic-card-bg); 
            padding: 40px 30px; 
            max-width: 650px; 
            width: 100%; 
            border: 1px solid var(--academic-border); 
            border-radius: 8px;
            box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
            box-sizing: border-box;
        }

        h2 { 
            color: var(--academic-blue); 
            margin-top: 0; 
            font-size: 1.8rem;
            border-bottom: 2px solid var(--academic-blue);
            padding-bottom: 12px;
            font-weight: 700;
            letter-spacing: -0.5px;
        }

        p {
            font-size: 1.1rem;
            line-height: 1.6;
            color: var(--academic-muted);
            margin-bottom: 30px;
        }

        label { 
            display: block; 
            margin: 24px 0 8px; 
            font-weight: 600; 
            font-size: 1.1rem;
            color: var(--academic-text);
        }

        select, input[type="file"] { 
            width: 100%; 
            padding: 14px; 
            background: var(--academic-card-bg); 
            border: 1px solid var(--academic-border); 
            color: var(--academic-text); 
            border-radius: 4px;
            box-sizing: border-box; 
            margin-bottom: 6px; 
            font-family: inherit;
            outline: none;
            font-size: 1.1rem;
            transition: border-color 0.2s, box-shadow 0.2s;
        }

        select:focus, input[type="file"]:focus {
            border-color: var(--academic-focus);
            box-shadow: 0 0 0 3px rgba(13, 110, 253, 0.15);
        }

        select:disabled {
            background-color: #e9ecef;
            color: var(--academic-muted);
            cursor: not-allowed;
        }

        .file-info { 
            font-size: 0.95rem; 
            color: var(--academic-muted); 
            margin-top: 6px; 
            margin-bottom: 20px; 
        }

        button { 
            width: 100%; 
            padding: 16px; 
            background: var(--academic-blue); 
            border: none; 
            border-radius: 4px;
            color: #ffffff; 
            font-weight: 600; 
            margin-top: 30px; 
            cursor: pointer; 
            font-size: 1.2rem; 
            letter-spacing: 0.5px;
            font-family: inherit;
            transition: background-color 0.2s;
        }

        button:hover { 
            background: #0a2246;
        }

        button:disabled { 
            background: #a5b5c9; 
            color: #ffffff;
            cursor: not-allowed; 
        }

        #status { 
            text-align: center; 
            margin-top: 25px; 
            font-weight: 600; 
            font-size: 1.1rem;
            line-height: 1.5;
            white-space: pre-line; 
            padding: 15px;
            border-radius: 4px;
            border: 1px solid transparent;
        }

        @media (max-width: 480px) {
            body {
                padding: 10px;
            }
            .card {
                padding: 25px 20px;
            }
            h2 {
                font-size: 1.5rem;
            }
            p {
                font-size: 1rem;
            }
            label {
                font-size: 1rem;
            }
            select, input[type="file"], button, #status {
                font-size: 1rem;
            }
        }
        /* ===== Letra M (color fijo, independiente del tema) ===== */
        .letra-m {
            color: #FF5A1F;
            font-weight: 900;
        }

        h2 small {
            font-size: 0.6em;
            font-weight: 600;
            color: var(--academic-muted);
            letter-spacing: 0;
        }

        /* ===== Estado del horario por grupo ===== */
        .estado-horario {
            margin-top: 10px;
            padding: 14px 16px;
            border-radius: 4px;
            border: 1px solid transparent;
            display: flex;
            flex-direction: column;
            gap: 4px;
            font-size: 1rem;
            line-height: 1.4;
        }
        .estado-horario strong { font-size: 1.05rem; }
        .estado-horario .cuenta {
            font-variant-numeric: tabular-nums;
            font-weight: 700;
        }
        .estado-horario.abierto {
            background: #d1e7dd; border-color: #a3cfbb; color: #0a3622;
        }
        .estado-horario.por-abrir {
            background: #fff3cd; border-color: #ffe69c; color: #664d03;
        }
        .estado-horario.cerrado,
        .estado-horario.sin-horario {
            background: #f8d7da; border-color: #f1aeb5; color: #58151c;
        }

        input[type="file"]:disabled {
            background-color: #e9ecef;
            cursor: not-allowed;
        }