https://imgur.com/a/iFv0FvS

// ==UserScript==
// @name         Count containers
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  Count containers
// @author       You
// @match        https://tankionline.com/play/
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    var style = document.createElement('style');
    style.type = 'text/css';
    style.textContent = `
    .counters-container {position: absolute; bottom: 20px; width: 100%; display: flex; justify-content: space-between; z-index: 2;} .left-half {width: 20%;}.right-half {width: 20%;}
    .Common-container .DeviceButtonComponentStyle-blockAlterations {z-index: 4; !important}
    input[type="number"]::-webkit-inner-spin-button, input[type="number"]::-webkit-outer-spin-button { -webkit-appearance: none; margin: 0;}`;

    document.head.appendChild(style);

    function getUserNickname() {
    var userInfoElement = document.querySelector('.UserInfoContainerStyle-textDecoration');
    if (userInfoElement) {
        var nickname = userInfoElement.textContent.trim();
        nickname = nickname.replace(/\[.*?\]/g, '').trim();
        return nickname;
    } else {
        return 'unknown';
    }
}

    function createCounterElement(id, title) {
        var userNickname = getUserNickname();
        var counterKey = `${userNickname}_${id}`;

        var counterElement = document.createElement('div');
        counterElement.style.padding = '10px';
        counterElement.style.border = '1px solid #ccc';
        counterElement.style.borderRadius = '5px';
        counterElement.style.backgroundColor = 'transparent';

        var counterLabel = document.createElement('span');
        counterLabel.innerHTML = `Открыто ${title} контейнеров: `;
        counterLabel.style.color = 'white';
        counterElement.appendChild(counterLabel);

        var counterInput = document.createElement('input');
        counterInput.style.webkitAppearance = 'none';
        counterInput.id = `${id}`;
        counterInput.type = "number";
        counterInput.value = localStorage.getItem(counterKey) || '0';
        counterInput.style.marginRight = '10px';
        counterInput.style.width = '50px';
        counterInput.style.background = 'transparent';
        counterInput.style.color = 'white';

        counterInput.addEventListener('focus', function() {
            this.value = '';
        });

        var previousValue;
counterInput.addEventListener('focus', function() {
    previousValue = parseInt(localStorage.getItem(counterKey)) || 0;
    this.value = '';
});

counterInput.addEventListener('blur', function() {
    var additionValue = parseInt(this.value);
    if (isNaN(additionValue) || this.value === '') {
        this.value = previousValue;
    } else {
        var newValue = previousValue + additionValue;
        localStorage.setItem(counterKey, newValue);
        this.value = newValue;
    }
});
        counterElement.appendChild(counterInput);

        var clearButton = document.createElement('button');
        clearButton.innerHTML = "Очистить";
        clearButton.style.cursor = 'pointer';
        clearButton.addEventListener('click', function() {
            localStorage.setItem(counterKey, 0);
            counterInput.value = '0';
        });
        counterElement.appendChild(clearButton);

        return counterElement;
    }

    function openContainer(containerType) {
        var userNickname = getUserNickname();
        var containerKey = `${userNickname}_${containerType}`;
        var currentValue = parseInt(localStorage.getItem(containerKey)) || 0;
        var newValue = currentValue + 1;
        localStorage.setItem(containerKey, newValue);
    }

    function setupObserver() {
        var observer = new MutationObserver(function(mutations) {
            var bottomBlock = document.querySelector('.ContainersComponentStyle-bottomBlock');
            if (bottomBlock) {
                var countersContainer = document.querySelector('.counters-container');
                if (countersContainer) {
                    countersContainer.parentNode.removeChild(countersContainer);
                }
                countersContainer = document.createElement('div');
                countersContainer.className = 'counters-container';
                countersContainer.style.flexDirection = 'column';
                countersContainer.style.width = '22%';
                countersContainer.style.left = '4.5%';

                var standardCounter = createCounterElement('standardContainerCount', 'обычных');
                countersContainer.appendChild(standardCounter);

                var ultraCounter = createCounterElement('epicContainerCount', 'ультра');
                countersContainer.appendChild(ultraCounter);

                bottomBlock.appendChild(countersContainer);

                observer.disconnect();
                checkIfBottomBlockDisappears(observer);
            }
        });

        observer.observe(document.body, {childList: true, subtree: true});
    }

    function checkIfBottomBlockDisappears(observer) {
        var bottomBlockCheck = setInterval(function() {
            var bottomBlock = document.querySelector('.ContainersComponentStyle-bottomBlock');
            if (!bottomBlock) {
                observer.observe(document.body, {childList: true, subtree: true});
                clearInterval(bottomBlockCheck);
            }
        }, 500);
    }

    window.addEventListener('load', setupObserver);
    window.addEventListener('load', setupObserver);
})();