/* Variables */

   :root {
       --bg-color: #f4f4f4;
       --bg-color-dark: #000000ec;

       --text-color: #333;
       --text-color-dark: #333;

       --border-shadow: rgba(0, 78, 245, 0.747);
       --border-shadow-dark: rgb(255, 0, 0);

       --container-bg: #fff;
       --container-bg-dark: #2c2c2c;
   }


   /* Reset básico y estilos generales */
   * {
       margin: 0;
       padding: 0;
       box-sizing: border-box;
       font-family: 'Arial', sans-serif;
   }

   body {
       line-height: 1.6;
       background-color: var(--bg-color);
       color: var(--text-color);
       padding: 20px;
       transition: background-color 0.3s ease, color 0.3s ease;
   }

   body.dark {
       line-height: 1.6;
       background-color: var(--bg-color-dark);
       color: var(--text-color-dark);
       padding: 20px;
   }

   header,
   main,
   footer {
       max-width: 1050px;

       margin: 0 auto;
       padding: 20px;
       background: var(--container-bg);
       border-radius: 8px;
       box-shadow: 0 2px 5px var(--border-shadow);
       margin-bottom: 20px;
       transition: background-color 0.3s ease, box-shadow 0.3s ease;
   }

   /* background: var(--container-bg-dark);*/
   header.dark,
   main.dark,
   footer.dark {
       box-shadow: 0 2px 5px var(--border-shadow-dark);
   }

   /* Estilos del encabezado */
   header {
       display: flex;
       flex-direction: column;
       align-items: flex-start;
       position: relative;
   }

   .main-content {
       flex: 2;
   }


   /* BTN cambio */
   #theme-toggle {
       position: absolute;
       right: 10px;
       top: 10px;
       background: none;
       border: none;
       font-size: 1.5rem;
       cursor: pointer;
   }

   h1 {
       color: #2c3e50;
       margin-bottom: 10px;
   }

   /* Estilos de navegación */
   nav ul {
       display: flex;
       justify-content: center;
       list-style: none;
       gap: 15px;
       margin-top: 15px;
   }

   nav a {
       text-decoration: none;
       color: #3498db;
       font-weight: bold;
   }

   /* Estilos del contenido principal */
   section {
       margin: 20px 0;
   }

   p {
       text-align: justify;
   }

   h2 {
       color: #2c3e50;
       border-bottom: 1px solid #eee;
       padding-bottom: 5px;
       margin-bottom: 10px;
   }

   h4 {
       color: #2c3e50;
       text-align: center;
       padding-bottom: 5px;
       margin-bottom: 10px;
   }

   /* Estilos del pie de página */
   footer {
       text-align: center;
       font-size: 0.9em;
       color: #7f8c8d;
   }

   .iconosFooter {
       text-align: end;
   }

   .icon-link {
       padding: 0.5em;
   }


   /* Responsive */
   @media (max-width: 600px) {
       body {
           padding: 10px;
       }

       nav ul {
           flex-direction: column;
           gap: 5px;
       }
   }

   /* Dropdown */
   .dropdown {
       position: relative;
   }

   .dropdown-menu {
       display: none;
       /* Añade un margen superior invisible para solapar el área del botón */
       margin-top: 10px;
       /* Y un padding superior negativo para compensar */
       padding-top: 10px;
       position: absolute;
       top: 100%;
       left: 0;
       background: #444;
       min-width: 160px;
       box-shadow: 0 8px 16px rgba(0, 0, 0, 0.2);
   }

   .dropdown:hover .dropdown-menu {
       display: block;
   }

   /* Triángulo/conector invisible entre botón y menú */
   .dropdown-menu::before {
       content: "";
       position: absolute;
       top: -10px;
       left: 20px;
       width: 100%;
       height: 10px;
       background: transparent;
   }

   .dropdown-menu li {
       padding: 10px;
   }

   .dropdown-menu a:hover {
       background: #007bff;
   }

   .padding-left {
       padding-left: 20px;
   }

   .aling-center {
       text-align: center;
   }

   .aling-left {
       text-align: left;
   }

   .sidebar {
       flex: 1;
       background: #f8f9fa;
       padding: 20px;
       border-radius: 8px;
       box-shadow: 0 2px 5px var(--border-shadow);
         margin-left: 20px;
   }
    .sidebar.dark {
         box-shadow: 0 2px 5px var(--border-shadow-dark);
    }

   /* Estilos para el sidebar */
   .sidebar h3 {
       color: #2c3e50;
       border-bottom: 1px solid #eee;
       padding-bottom: 10px;
       margin-bottom: 15px;
   }

   .sidebar ul {
       padding-left: 20px;
       margin-bottom: 20px;
   }

   .sidebar li {
       margin-bottom: 8px;
   }

   .highlight-box {
       background: #e3f2fd;
       padding: 15px;
       border-radius: 8px;
       margin-top: 20px;
   }

   .signup-button {
       background-color: #3498db;
       color: white;
       border: none;
       padding: 10px 15px;
       border-radius: 5px;
       cursor: pointer;
       margin-top: 10px;
       width: 100%;
   }

   .signup-button:hover {
       background-color: #2980b9;
   }

   /* Responsive */
   @media (max-width: 768px) {
       .two-column-layout {
           flex-direction: column;
       }

       .three-column-layout {
           flex-direction: column;
       }

       .sidebar {
           margin-top: 20px;
       }
   }

   .two-column-layout {
       display: flex;
       gap: 30px;
   }

   .three-column-layout {
       display: flex;
   }

   .timeline {
       position: relative;
       list-style: none;
       padding-left: 40px;
       /* espacio para la línea */
       margin: 20px 0;
   }

   .timeline::before {
       content: "";
       position: absolute;
       top: 0;
       left: 15px;
       /* centrado respecto a los puntos */
       width: 2px;
       height: 100%;
       background-color: #333;
   }

   .timeline li {
       position: relative;
       margin-bottom: 30px;
   }

   .timeline li::before {
       content: "";
       position: absolute;
       left: -34px;
       /* centra el punto con la línea */
       top: 5px;
       width: 16px;
       height: 16px;
       background-color: white;
       border: 2px solid #333;
       border-radius: 50%;
   }

   .timeline .year {
       font-weight: bold;
       margin-bottom: 5px;
   }

   .timeline .desc {
       color: #555;
   }

/* ==== ToDo List Styles ==== */

.todo-container {
    background-color: var(--container-bg);
    color: var(--text-color);
    border-radius: 12px;
    padding: 1.5rem 2rem;
    box-shadow: 0 0 10px var(--border-shadow);
    transition: all 0.3s ease;
}

.dark-mode .todo-container {
    background-color: var(--container-bg-dark);
    color: var(--text-color-dark);
    box-shadow: 0 0 10px var(--border-shadow-dark);
}

/* Encabezado de la sección */
.todo-container h2 {
    font-size: 1.6rem;
    font-weight: 700;
    margin-bottom: 1rem;
    border-bottom: 2px solid var(--border-shadow);
    padding-bottom: 0.5rem;
}

/* Texto descriptivo */
.todo-description {
    margin-bottom: 1rem;
    font-size: 0.95rem;
    color: #555;
}

.dark-mode .todo-description {
    color: #ccc;
}

/* Lista de tareas */
.todo-list {
    list-style: none;
    padding-left: 0;
}

.todo-item {
    background-color: #f9f9f9;
    border-radius: 8px;
    padding: 0.7rem 1rem;
    margin-bottom: 0.6rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    box-shadow: 0 2px 5px rgba(0,0,0,0.05);
    transition: transform 0.2s ease, background-color 0.3s;
}

.todo-item:hover {
    transform: translateY(-2px);
    background-color: #eef3ff;
}

.dark-mode .todo-item {
    background-color: #3b3b3b;
}

.dark-mode .todo-item:hover {
    background-color: #4a4a4a;
}

/* Icono o marca de tarea (si lo añades más adelante) */
.todo-item::before {
    content: "✔️";
    margin-right: 0.5rem;
    font-size: 1rem;
}

/* Enlaces o botones dentro de la lista */
.todo-item a {
    color: var(--border-shadow);
    text-decoration: none;
    font-weight: 600;
}

.todo-item a:hover {
    text-decoration: underline;
}

/* Transición entre modos */
body, .todo-container, .todo-item {
    transition: background-color 0.3s, color 0.3s, box-shadow 0.3s;
}