:root {
    --background: rgba(0, 0, 0, 0.9);
    --primary-color: #1C1D20;
    --secondary-color: #4A4D57;
    --accent-color: #00FFC4;
    --text-color: #fff;
}

* {
    margin: 0;
    padding: 0;
}

html {
   font-family: "Outfit", sans-serif;
   font-size: 16px;  
   color: var(--text-color);
}

body {
    background-color: var(--background);
    align-items: center;
    display: flex;
    justify-content: center;
    min-height: 100vh;
    padding: 10px;
    flex-direction: column;
    align-items: center;
}

h1 {
    margin-top: 100px;
    margin-bottom: 80px;
    font-size: 3rem;
    font-weight: 800;
    text-transform: uppercase;
    text-align: center;
    color: var(--accent-color);
    font-family: "Orbitron", sans-serif;
}

/* Glow for accent text (like h1) */
h1:hover {
    text-shadow: 0 0 10px var(--accent-color), 
                 0 0 20px var(--accent-color), 
                 0 0 40px var(--accent-color);
    transition: 300ms ease;
}

.todoApp {
    width: 700px;
    max-width: 100%;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

#todo-input {
    box-sizing: border-box;
    padding: 12px 20px;
    width: 100%;
    background: none;
    border: 2px solid var(--secondary-color);
    border-radius: 1000px;
    font: inherit;
    color: var(--text-color);
}

#todo-input:focus {
    outline: none;
}

form {
    position: relative;
}

#add-button {
    position: absolute;
    top: 0;
    right: 0;
    background-color: var(--accent-color);
    height: 100%;
    padding: 0 30px;
    border: none;
    border-radius: 1000px;
    font: inherit;
    color: var(--background);
    cursor: pointer;
}

#add-button:hover {
    background-color: var(--accent-color);
    box-shadow: 0 0 15px var(--accent-color), 
                0 0 30px var(--accent-color), 
                0 0 45px var(--accent-color);
    transition: 300ms ease;
}

.todo {
    margin-bottom: 10px;
    padding: 0 16px;
    background-color: var(--primary-color);
    border-radius: 15px;
    display: flex;
    align-items: center;
}

.todo .todo-text {
    padding: 15px;
    padding-right: 0;
    flex-grow: 1;
    transition: 200ms ease;
}

.delete-button {
    padding: 3px;
    background: none;
    border: none;
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    color: var(--accent-color);
}

.delete-button:hover {
    color: red;
    transition: 200ms ease;
    text-shadow: 0 0 10px red, 0 0 20px red;
}

.custom-checkbox {
    border: 2px solid var(--accent-color);
    border-radius: 20%;
    min-height: 20px;
    min-width: 20px;
    display: flex;
    justify-items: center;
    align-items: center;
    flex-shrink: 0;
    transition: 200ms ease;
    cursor: pointer;
}

.custom-checkbox:hover {
    box-shadow: 0 0 10px var(--accent-color), 
                0 0 20px var(--accent-color);
}

.custom-checkbox p {
    color: transparent;
}

input[type="checkbox"]:checked ~ .custom-checkbox {
    background-color: var(--accent-color);
}

input[type="checkbox"]:checked ~ .custom-checkbox p {
    color: var(--primary-color);
}

input[type="checkbox"]:checked ~ .todo-text {
    text-decoration: line-through;
    color: var(--secondary-color);
}

input[type="checkbox"] {
    display: none;
}

/* Tablet responsiveness */
@media(max-width: 900px) {
    .todoApp {
        width: 90%;
    }
}

/* Small screens already covered by your @media(max-width: 500px) */

/* Large screens - scale up smoothly */
@media(min-width: 1400px) {
    html {
        font-size: 18px;
    }

    h1 {
        font-size: 4rem;
    }

    #todo-input {
        padding: 16px 24px;
        font-size: 1.2rem;
    }

    #add-button {
        padding: 0 40px;
        font-size: 1.1rem;
    }
}