Websites that look designed and feel engineered.

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;

import {Ownable} from "@openzeppelin/contracts/access/Ownable.sol";

contract TipJar is Ownable {
    mapping(address => uint256) public balances;
    bool public paused;

    event Deposited(address indexed from, uint256 amount);
    event Withdrawn(address indexed to, uint256 amount);

    constructor() Ownable(msg.sender) {}

    function deposit() external payable {
        require(!paused, "Deposits are paused");
        balances[msg.sender] += msg.value;
        emit Deposited(msg.sender, msg.value);
    }

    function withdraw(uint256 amount) external {
        require(balances[msg.sender] >= amount, "Insufficient balance");
        balances[msg.sender] -= amount; // state changes first
        (bool ok, ) = msg.sender.call{value: amount}(""); // then the call
        require(ok, "Transfer failed");
        emit Withdrawn(msg.sender, amount);
    }

    function setPaused(bool value) external onlyOwner {
        paused = value;
    }
}