Uncaught TypeError: Cannot read property 'style' of null

/*
GAME RULES:

- The game has 2 players, playing in rounds
- In each turn, a player rolls a dice as many times as he whishes. Each result get added to his ROUND score
- BUT, if the player rolls a 1, all his ROUND score gets lost. After that, it's the next player's turn
- The player can choose to 'Hold', which means that his ROUND score gets added to his GLBAL score. After that, it's the next player's turn
- The first player to reach 100 points on GLOBAL score wins the game

*/
var scores, roundScore, activePlayer, gamePlaying;

init();

//document.querySelector('#current-' + activePlayer).textContent = dice; // SETTER
//document.querySelector('#current-' + activePlayer).innerHTML = '<em>' + dice + '</em>';

//var x = document.querySelector('#score-0').textContent; // GETTER
//console.log(x);



// Events: Notifications that are sent to notify the code that something happened
// on the webpage;
// Examples: clicking a button, resizing a window, scrolling down, or pressing
// a key.
// Event listener: a function that performs an action based on a certain event.
// It waits for a specific event to happen.

//var lastDice;
document.querySelector('.btn-roll').addEventListener('click', function() {
    if(gamePlaying) {

        // 1. Random number
        var dice1 = Math.floor(Math.random() * 6) + 1;
        var dice2 = Math.floor(Math.random() * 6) + 1;
        //Check for double 6





        // 2. Display the result
        document.getElementById('dice-1').style.display = 'block';
        document.getElementById('dice-2').style.display = 'block';

        document.getElementById('dice-1').src = 'dice-' + dice1 + '.png';
        document.getElementById('dice-1').src = 'dice-' + dice2 + '.png';

        // 3. Update the round score IF the rolled number was NOT 1
        if (dice1 !== 1 && dice2 !== 1) {
            //Add score
            roundScore += dice1 + dice2;
            document.querySelector('#current-' + activePlayer).textContent = roundScore;
        } else {
            //Next player
            nextPlayer();
        }

        /*
        if (dice === 6 && lastDice === 6) {
            scores[activePlayer] = 0;
            document.querySelector('#score-' + activePlayer).textContent = '0';
            nextPlayer();
        } else if (dice > 1) {
            //Add score
            roundScore += dice;
            document.querySelector('#current-' + activePlayer).textContent = roundScore;
        } else {
            //Next player
            nextPlayer();
        }
        lastDice = dice;
        */

    }
});

// Implementing Our 'Hold' Function and the DRY Principle
document.querySelector('.btn-hold').addEventListener('click', function() {
    if(gamePlaying) {
        // Add current score to global score
        scores[activePlayer] += roundScore;
        // Update the UI
        document.querySelector('#score-' + activePlayer).textContent =
        scores[activePlayer];

        var input = document.querySelector('.final-score').value;
        var winningScore;

        // Undefined, 0, null, or "" are COERCED to false. Anything else is true.
        if(input) {
            var winningScore = input;
        } else {
            winningScore = 100;
        }

        // Check if player won the game
        if (scores[activePlayer] >= winningScore) {
            gamePlaying = false;
            document.querySelector('#name-' + activePlayer).textContent =
            'WINNER!';
            document.getElementById('dice-1').style.display = 'none';
            document.getElementById('dice-2').style.display = 'none';
            document.querySelector('.player-' + activePlayer + '-panel').classList.add('winner');
            document.querySelector('.player-' + activePlayer + '-panel').classList.remove('active');

        } else {
            nextPlayer();
    }
    }

});

function nextPlayer() {
    activePlayer === 0 ? activePlayer = 1 : activePlayer = 0;
    roundScore = 0;
    document.getElementById('current-0').textContent = '0';
    document.getElementById('current-1').textContent = '0';

    document.querySelector('.player-0-panel').classList.toggle('active');
    document.querySelector('.player-1-panel').classList.toggle('active');

    document.getElementById('dice-1').style.display = 'none';
    document.getElementById('dice-2').style.display = 'none';
}

// Creating A Game Initialization Function
document.querySelector('.btn-new').addEventListener('click', init);

function init() {
    scores = [0, 0];
    roundScore = 0;
    activePlayer = 0;
    gamePlaying = true;
    document.getElementById('dice-1').style.display = 'none';
    document.getElementById('dice-2').style.display = 'none';
    document.getElementById('score-0').textContent = '0';
    document.getElementById('score-1').textContent = '0';
    document.getElementById('current-0').textContent = '0';
    document.getElementById('current-1').textContent = '0';

    document.getElementById('name-0').textContent = 'Player 1';
    document.getElementById('name-1').textContent = 'Player 2';
    document.querySelector('.player-0-panel').classList.remove('winner');
    document.querySelector('.player-1-panel').classList.remove('winner');
    document.querySelector('.player-0-panel').classList.remove('active');
    document.querySelector('.player-1-panel').classList.remove('active');
    document.querySelector('.player-0-panel').classList.add('active');
}

// Finishing Touches

// Coding Challenge 6