body {
            font-family: 'Segoe UI', Arial, sans-serif;
            max-width: 900px;
            margin: 0 auto;
            padding: 20px;
            line-height: 1.8;
            background-color: #f8fafc;
            color: #333;
        }
        h1 {
            text-align: center;
            color: #2c5282;
            margin-bottom: 30px;
        }
        .controls {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 20px;
            flex-wrap: wrap;
            gap: 10px;
            background: #edf2f7;
            padding: 10px;
            border-radius: 5px;
        }
        .controls button {
            padding: 8px 15px;
            border: none;
            border-radius: 4px;
            cursor: pointer;
            font-size: 14px;
            transition: background 0.3s;
        }
        #increase-font {
            background: #48bb78;
            color: white;
        }
        #increase-font:hover {
            background: #38a169;
        }
        #decrease-font {
            background: #ed8936;
            color: white;
        }
        #decrease-font:hover {
            background: #dd6b20;
        }
        #clear-progress {
            background: #e53e3e;
            color: white;
        }
        #clear-progress:hover {
            background: #c53030;
        }
        .progress {
            font-size: 14px;
            color: #4a5568;
        }
        .paragraph {
            margin-bottom: 25px;
            background: white;
            padding: 20px;
            border-radius: 8px;
            box-shadow: 0 2px 8px rgba(0,0,0,0.1);
        }
        .sentence {
            display: inline;
            cursor: pointer;
            padding: 2px 5px;
            border-radius: 3px;
            transition: background 0.2s;
        }
        .sentence:hover {
            background: #e6fffa;
        }
        .sentence.active {
            background: #b2f5ea;
            font-weight: bold;
        }
        .sentence.read {
            color: #2f855a;
        }
        .translation-btn {
            display: inline-block;
            margin-left: 5px;
            padding: 2px 8px;
            background: #4299e1;
            color: white;
            border: none;
            border-radius: 3px;
            font-size: 12px;
            cursor: pointer;
            vertical-align: middle;
        }
        .translation-btn:hover {
            background: #3182ce;
        }
        .translation {
            display: none;
            margin: 5px 0 10px 20px;
            padding: 8px;
            background: #fefcbf;
            border-left: 4px solid #ecc94b;
            font-style: italic;
            font-size: 0.95em;
            color: #744210;
        }
        .word-definition {
            position: absolute;
            background: #2d3748;
            color: white;
            padding: 10px;
            border-radius: 5px;
            max-width: 200px;
            font-size: 12px;
            z-index: 1000;
            display: none;
            box-shadow: 0 4px 6px rgba(0,0,0,0.2);
        }
        @media (max-width: 600px) {
            body {
                padding: 10px;
            }
            .paragraph {
                padding: 15px;
            }
            .controls {
                flex-direction: column;
                align-items: stretch;
            }
            .controls button {
                width: 100%;
                margin-bottom: 5px;
            }
        }