/* ── To-Do List ── */
#todo-form {
    width: 50%;
    max-width: 600px;
    margin: 200px auto;
    background-color: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.15);
    border-radius: 16px;
    padding: 30px;
    color: white;
    z-index: 1001;
    position: relative;
}

#todo-form h3 {
    font-size: 2rem;
    margin-top: 0;
    margin-bottom: 20px;
    color: white;
    z-index: 1001;
    position: relative;
}

.todo-list {
    list-style: none;
    padding: 0;
    margin: 0 0 20px 0;
    z-index: 1001;
    position: relative;
}

.todo-list li {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 12px;
    border-radius: 8px;
    margin-bottom: 8px;
    background-color: rgba(255, 255, 255, 0.07);
    transition: background-color 0.2s ease;
    z-index: 1001;
    position: relative;
}

.todo-list li:hover {
    background-color: rgba(255, 255, 255, 0.12);
}

.todo-list li input[type="checkbox"] {
    width: 18px;
    height: 18px;
    accent-color: var(--UIGreen);
    cursor: pointer;
    flex-shrink: 0;
}

.todo-list li span {
    flex: 1;
    font-size: 1.1rem;
    transition: opacity 0.2s ease, text-decoration 0.2s ease;
}

.todo-list li.completed span {
    text-decoration: line-through;
    opacity: 0.45;
}

.todo-delete {
    background: transparent;
    border: 1px solid rgba(255, 80, 80, 0.5);
    color: rgba(255, 100, 100, 0.8);
    border-radius: 6px;
    padding: 4px 10px;
    font-size: 0.8rem;
    cursor: pointer;
    flex-shrink: 0;
    transition: background-color 0.2s ease, color 0.2s ease;
}

.todo-delete:hover {
    background-color: rgba(255, 80, 80, 0.2);
    color: white;
}

.todo-input-row {
    display: flex;
    gap: 10px;
}

#new-todo {
    flex: 1;
    padding: 10px 14px;
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 8px;
    background-color: rgba(255, 255, 255, 0.08);
    color: white;
    font-size: 1rem;
    outline: none;
    transition: border-color 0.2s ease;
}

#new-todo::placeholder {
    color: rgba(255, 255, 255, 0.35);
}

#new-todo:focus {
    border-color: var(--UIGreen);
}

#todo-form button {
    display: block;
    margin-top: 10px;
    background-color: var(--UIGreen);
    color: white;
    font-weight: bold;
    padding: 10px 40px;
    border-radius: 25px;
    border: 2px solid var(--UIGreen);
    cursor: pointer;
    font-size: 1.1rem;
    transition: all 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

#todo-form button:hover {
    background-color: yellow;
    color: rgb(220, 0, 0);
    border: 2px solid black;
    transform: translateY(-3px) scale(1.1);
}

#todo-form button:active {
    transform: translateY(-1px) scale(0.98);
    background-color: black;
    color: var(--UIGreen);
    border: 2px solid var(--UIGreen);
}

/* Back button */
.back-button {
    position: absolute;
    top: 100px;
    left: 20px;
    z-index: 1001;
    background-color: rgb(35, 31, 132);
    color: white;
    font-weight: bold;
    font-size: 1.2rem;
    text-decoration: none;
    padding: 14px 28px;
    border-radius: 25px;
    transition: all 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.3);
    z-index: 1001;
}

.back-button:hover {
    background-color: yellow;
    color: rgb(220, 0, 0);
    border: 2px solid black;
    transform: translateY(-3px) scale(1.1);
    box-shadow: 0 0 25px rgba(255, 255, 255, 0.9);
}

.back-button:active {
    transform: translateY(-1px) scale(0.98);
    background-color: black;
    color: var(--UIGreen);
    border: 2px solid var(--UIGreen);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.4);
}

@media (max-width: 768px) {
    #todo-form {
        width: 90%;
        margin: 140px auto 40px;
        padding: 24px 20px;
    }

    .back-button {
        top: 80px;
        left: 16px;
        font-size: 1rem;
        padding: 10px 20px;
    }

    #todo-form h3 {
        font-size: 1.6rem;
    }

    .todo-list li span {
        font-size: 1rem;
    }

    #todo-form button {
        width: 100%;
        padding: 12px 20px;
        font-size: 1rem;
    }
}

@media (max-width: 480px) {
    #todo-form {
        width: 94%;
        margin: 120px auto 32px;
    }

    .todo-input-row {
        flex-direction: column;
        gap: 8px;
    }

    #new-todo {
        width: 100%;
    }

    #todo-form button {
        margin-top: 0;
    }
}