* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            background: #2c5f41;
            min-height: 100vh;
            
        }

        .container {
            max-width: 900px;
            margin: 0px auto;
            background: rgba(255, 255, 255, 0.95);
            /* border-radius: 20px; */
            box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
            overflow: hidden;
            /* backdrop-filter: blur(10px); */
        }

        .header {
            background: #2c3e50;
            color: white;
            padding: 40px 30px;
            text-align: center;
            position: relative;
            overflow: hidden;
        }

        .header::before {
            content: '';
            position: absolute;
            top: -50%;
            left: -50%;
            width: 200%;
            height: 200%;
            background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><circle cx="50" cy="50" r="2" fill="rgba(255,255,255,0.1)"/></svg>') repeat;
            animation: float 20s linear infinite;
        }

        @keyframes float {
            0% { transform: translate(0, 0) rotate(0deg); }
            100% { transform: translate(-50px, -50px) rotate(360deg); }
        }

        .header h1 {
            font-size: 2.5em;
            margin-bottom: 10px;
            position: relative;
            z-index: 1;
        }

        .header .subtitle {
            font-size: 1.2em;
            opacity: 0.9;
            position: relative;
            z-index: 1;
        }

        .content {
            padding: 40px 30px;
        }

        .section {
            margin-bottom: 40px;
            opacity: 0;
            animation: fadeInUp 0.8s ease-out forwards;
        }

        .section:nth-child(1) { animation-delay: 0.2s; }
        .section:nth-child(2) { animation-delay: 0.4s; }
        .section:nth-child(3) { animation-delay: 0.6s; }
        .section:nth-child(4) { animation-delay: 0.8s; }
        .section:nth-child(5) { animation-delay: 1.0s; }
        .section:nth-child(6) { animation-delay: 1.2s; }
        .section:nth-child(7) { animation-delay: 1.4s; }
        .section:nth-child(8) { animation-delay: 1.6s; }
        .section:nth-child(9) { animation-delay: 1.8s; }
        .section:nth-child(10) { animation-delay: 2.0s; }

        @keyframes fadeInUp {
            from {
                opacity: 0;
                transform: translateY(30px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        .section h2 {
            color: #333;
            font-size: 1.8em;
            margin-bottom: 20px;
            border-bottom: 3px solid #4ecdc4;
            padding-bottom: 10px;
            display: inline-block;
        }

        .definition {
            background: #34495e;
            color: white;
            padding: 30px;
            border-radius: 15px;
            font-size: 1.1em;
            line-height: 1.6;
            margin-bottom: 20px;
            box-shadow: 0 10px 30px rgba(52, 73, 94, 0.3);
        }

        .percent-symbol {
            font-size: 2em;
            font-weight: bold;
            color: #ff6b6b;
            display: inline-block;
            margin: 0 10px;
        }

        .example {
            background: #e8f5e8;
            padding: 20px;
            border-radius: 10px;
            border-left: 5px solid #4ecdc4;
            margin: 20px 0;
        }

        .conversion-tip {
            background: linear-gradient(135deg, #e8f5e8, #d4edda);
            border: 1px solid #4ecdc4;
            border-radius: 15px;
            padding: 25px;
            margin: 20px 0;
            box-shadow: 0 5px 15px rgba(78, 205, 196, 0.1);
        }

        .conversion-tip h3 {
            color: #2c3e50;
            font-size: 1.3em;
            margin-bottom: 15px;
            text-align: center;
            position: relative;
        }

        .conversion-tip h3:after {
            content: '';
            display: block;
            width: 50px;
            height: 3px;
            background: #4ecdc4;
            margin: 10px auto 0;
            border-radius: 2px;
        }

        .conversion-tip p {
            color: #2c3e50;
            font-size: 1.1em;
            text-align: center;
            margin-bottom: 20px;
            font-weight: 500;
        }

        .conversion-examples {
            display: flex;
            flex-direction: column;
            gap: 15px;
        }

        .conversion-example {
            display: flex;
            align-items: center;
            justify-content: center;
            background: white;
            padding: 20px;
            border-radius: 12px;
            box-shadow: 0 3px 10px rgba(0, 0, 0, 0.08);
            flex-wrap: wrap;
            gap: 15px;
            border: 1px solid #e9ecef;
            transition: all 0.3s ease;
        }

        .conversion-example:hover {
            transform: translateY(-2px);
            box-shadow: 0 5px 20px rgba(0, 0, 0, 0.12);
        }

        .percent-value {
            background: linear-gradient(135deg, #ff6b6b, #ee5a24);
            color: white;
            padding: 10px 18px;
            border-radius: 25px;
            font-weight: bold;
            font-size: 1.1em;
            box-shadow: 0 3px 8px rgba(255, 107, 107, 0.3);
        }

        .arrow {
            font-size: 1.8em;
            color: #4ecdc4;
            font-weight: bold;
            text-shadow: 0 2px 4px rgba(78, 205, 196, 0.3);
        }

        .decimal-value {
            background: linear-gradient(135deg, #4ecdc4, #44a08d);
            color: white;
            padding: 10px 18px;
            border-radius: 25px;
            font-weight: bold;
            font-size: 1.1em;
            box-shadow: 0 3px 8px rgba(78, 205, 196, 0.3);
        }

        .explanation {
            font-size: 0.95em;
            color: #6c757d;
            font-style: italic;
            flex-basis: 100%;
            text-align: center;
            margin-top: 8px;
            background: #f8f9fa;
            padding: 5px 10px;
            border-radius: 15px;
        }

        .common-percents {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: 20px;
            margin: 20px 0;
        }

        .percent-card {
            background: #34495e;
            color: white;
            padding: 20px;
            border-radius: 15px;
            text-align: center;
            transform: translateY(0);
            transition: all 0.3s ease;
            cursor: pointer;
            position: relative;
            display: flex;
            flex-direction: column;
            align-items: center;
        }

        .percent-circle {
            width: 80px;
            height: 80px;
            border-radius: 50%;
            margin-bottom: 15px;
            position: relative;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: bold;
            font-size: 1.2em;
            color: #333;
        }

        .percent-circle.p50 {
            background: conic-gradient(#4ecdc4 0deg 180deg, #f0f0f0 180deg 360deg);
        }

        .percent-circle.p25 {
            background: conic-gradient(#4ecdc4 0deg 90deg, #f0f0f0 90deg 360deg);
        }

        .percent-circle.p75 {
            background: conic-gradient(#4ecdc4 0deg 270deg, #f0f0f0 270deg 360deg);
        }

        .percent-circle.p100 {
            background: #4ecdc4;
        }

        .percent-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 15px 30px rgba(102, 126, 234, 0.4);
        }

        .percent-card .percent {
            font-size: 1.5em;
            font-weight: bold;
            margin-bottom: 10px;
        }

        .percent-card .equivalents {
            font-size: 0.9em;
            opacity: 0.9;
        }

        .interactive-circle {
            width: 100px;
            height: 100px;
            border-radius: 50%;
            background: conic-gradient(#4ecdc4 0deg 90deg, #f0f0f0 90deg 360deg);
            margin: 20px auto;
            position: relative;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: bold;
            color: #333;
            animation: rotate 3s ease-in-out infinite;
        }

        @keyframes rotate {
            0%, 100% { transform: rotate(0deg); }
            50% { transform: rotate(180deg); }
        }

        .highlight {
            background: #fff3cd;
            padding: 2px 6px;
            border-radius: 4px;
            font-weight: bold;
        }

        /* Quiz Styles */
        .quiz-header {
            background: linear-gradient(135deg, #ff6b6b, #ee5a24);
            color: white;
            padding: 40px 30px;
            text-align: center;
            margin: 40px -30px 30px -30px;
            
        }

        .quiz-header h2 {
            font-size: 2.2em;
            margin-bottom: 10px;
            border: none;
            color: white;
        }

        .explanation-section {
            background: linear-gradient(135deg, #f6f8ff 0%, #e8f0fe 100%);
            border-radius: 20px;
            padding: 30px;
            margin-bottom: 40px;
            box-shadow: 0 8px 25px rgba(0, 0, 0, 0.08);
            border: 2px solid #4ecdc4;
        }

        .explanation-section h3 {
            color: #2c3e50;
            margin-bottom: 20px;
            font-size: 1.6em;
            text-align: center;
            border-bottom: 3px solid #4ecdc4;
            padding-bottom: 10px;
            display: inline-block;
            width: 100%;
        }

        .explanation-section p {
            color: #2d3748;
            line-height: 1.6;
            margin-bottom: 25px;
            font-size: 1.1em;
        }

        .method {
            background: white;
            padding: 20px;
            border-radius: 15px;
            margin-bottom: 20px;
            box-shadow: 0 4px 15px rgba(0, 0, 0, 0.05);
            border-left: 4px solid #4ecdc4;
        }

        .method h4 {
            color: #ff6b6b;
            margin-bottom: 15px;
            font-size: 1.2em;
        }

        .method ol {
            margin-left: 20px;
        }

        .method li {
            margin-bottom: 8px;
            color: #2d3748;
            line-height: 1.5;
        }

        .method ul {
            margin-left: 20px;
        }

        .method ul li {
            margin-bottom: 8px;
            color: #2d3748;
            line-height: 1.5;
        }

        .formula-box {
            background: #34495e;
            color: white;
            padding: 20px;
            border-radius: 15px;
            text-align: center;
            margin-top: 25px;
        }

        .formula-box h4 {
            margin-bottom: 15px;
            font-size: 1.3em;
        }

        .formula {
            font-size: 1.4em;
            font-weight: bold;
            background: white; 
            padding: 15px;
            border-radius: 10px;
            margin: 0;
        }

        .quiz-section {
            margin-bottom: 30px;
            padding: 25px;
            background: white;
            border-radius: 15px;
            box-shadow: 0 8px 25px rgba(0, 0, 0, 0.08);
            border-left: 5px solid #4ecdc4;
            transition: transform 0.3s ease, box-shadow 0.3s ease;
        }

        .quiz-section:hover {
            transform: translateY(-3px);
            box-shadow: 0 12px 35px rgba(0, 0, 0, 0.12);
        }

        .question {
            font-size: 1.3em;
            font-weight: bold;
            margin-bottom: 20px;
            color: #2d3748;
        }

        .options {
            display: grid;
            gap: 12px;
        }

        .option {
            display: flex;
            align-items: center;
            padding: 15px;
            border: 2px solid #e2e8f0;
            border-radius: 10px;
            cursor: pointer;
            transition: all 0.3s ease;
            background: #f8fafc;
        }

        .option:hover {
            border-color: #4ecdc4;
            background: #e8f5e8;
            transform: translateX(5px);
        }

        .option.selected {
            border-color: #4ecdc4;
            background: #e8f5e8;
            box-shadow: 0 4px 12px rgba(78, 205, 196, 0.15);
        }

        .option.correct {
            border-color: #38a169;
            background: #f0fff4;
            color: #22543d;
        }

        .option.incorrect {
            border-color: #e53e3e;
            background: #fed7d7;
            color: #742a2a;
        }

        .option input[type="radio"] {
            margin-right: 12px;
            transform: scale(1.2);
        }

        .submit-section {
            text-align: center;
            margin-top: 40px;
            padding: 25px;
            background: white;
            border-radius: 15px;
            box-shadow: 0 8px 25px rgba(0, 0, 0, 0.08);
        }

        .submit-btn {
            background: linear-gradient(135deg, #4ecdc4, #44a08d);
            color: white;
            padding: 15px 40px;
            border: none;
            border-radius: 25px;
            font-size: 1.1em;
            font-weight: bold;
            cursor: pointer;
            transition: all 0.3s ease;
            box-shadow: 0 8px 20px rgba(78, 205, 196, 0.3);
        }

        .submit-btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 12px 30px rgba(78, 205, 196, 0.4);
        }

        .submit-btn:disabled {
            opacity: 0.6;
            cursor: not-allowed;
        }

        .results {
            margin-top: 30px;
            padding: 25px;
            background: linear-gradient(135deg, #e8f5e8, #d4edda);
            border-radius: 15px;
            border: 2px solid #4ecdc4;
            text-align: center;
            display: none;
        }

        .score {
            font-size: 2em;
            font-weight: bold;
            color: #ff6b6b;
            margin-bottom: 15px;
        }

        .reset-btn {
            background: #ff6b6b;
            color: white;
            padding: 12px 30px;
            border: none;
            border-radius: 20px;
            font-size: 1em;
            font-weight: bold;
            cursor: pointer;
            margin-top: 15px;
            transition: all 0.3s ease;
        }

        .reset-btn:hover {
            background: #ee5a24;
            transform: translateY(-2px);
        }

        .question-number {
            background: #ff6b6b;
            color: white;
            padding: 8px 15px;
            border-radius: 20px;
            font-size: 0.9em;
            margin-bottom: 15px;
            display: inline-block;
            font-weight: bold;
        }