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

        body {
            font-family: 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
            min-height: 100vh;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            display: flex;
            justify-content: center;
            align-items: center;
            padding: 20px;
        }

        .container {
            background: #fff;
            border-radius: 24px;
            box-shadow: 0 20px 60px rgba(0, 0, 0, 0.15);
            width: 100%;
            max-width: 520px;
            overflow: hidden;
        }

        .header {
            background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
            padding: 28px 32px;
            text-align: center;
            color: #fff;
        }

        .header h1 { font-size: 22px; font-weight: 700; letter-spacing: 1px; }
        .header p { font-size: 13px; opacity: 0.9; margin-top: 6px; }

        .progress-bar {
            display: flex;
            padding: 20px 32px 0;
            gap: 6px;
        }

        .progress-step {
            flex: 1;
            height: 4px;
            border-radius: 4px;
            background: #eee;
            transition: background 0.4s ease;
        }

        .progress-step.active { background: linear-gradient(90deg, #667eea, #764ba2); }
        .progress-step.done { background: #f5576c; }

        .content {
            padding: 28px 32px 32px;
            min-height: 340px;
        }

        .step {
            display: none;
            animation: fadeIn 0.4s ease;
        }

        .step.active { display: block; }

        @keyframes fadeIn {
            from { opacity: 0; transform: translateY(12px); }
            to { opacity: 1; transform: translateY(0); }
        }

        .step-title { font-size: 18px; font-weight: 700; color: #333; margin-bottom: 6px; }
        .step-desc { font-size: 13px; color: #888; margin-bottom: 22px; }

        .pet-options { display: flex; gap: 16px; }

        .pet-card {
            flex: 1;
            border: 2px solid #e8e8e8;
            border-radius: 16px;
            padding: 24px 16px;
            text-align: center;
            cursor: pointer;
            transition: all 0.3s ease;
            background: #fafafa;
        }

        .pet-card:hover {
            border-color: #c084fc;
            transform: translateY(-2px);
            box-shadow: 0 6px 20px rgba(192, 132, 252, 0.15);
        }

        .pet-card.selected {
            border-color: #764ba2;
            background: linear-gradient(135deg, #f3e8ff 0%, #fce7f3 100%);
            box-shadow: 0 6px 20px rgba(118, 75, 162, 0.2);
        }

        .pet-card .icon { font-size: 48px; margin-bottom: 10px; }
        .pet-card .label { font-size: 16px; font-weight: 600; color: #333; }

        .options { display: flex; flex-direction: column; gap: 10px; }

        .option-btn {
            border: 2px solid #e8e8e8;
            border-radius: 12px;
            padding: 14px 18px;
            text-align: left;
            cursor: pointer;
            transition: all 0.25s ease;
            background: #fafafa;
            font-size: 15px;
            color: #333;
            display: flex;
            align-items: center;
            gap: 10px;
        }

        .option-btn:hover { border-color: #c084fc; background: #fdf4ff; }

        .option-btn.selected {
            border-color: #764ba2;
            background: linear-gradient(135deg, #f3e8ff 0%, #fce7f3 100%);
            font-weight: 600;
        }

        .option-btn .dot {
            width: 20px;
            height: 20px;
            border-radius: 50%;
            border: 2px solid #ccc;
            flex-shrink: 0;
            display: flex;
            align-items: center;
            justify-content: center;
            transition: all 0.25s ease;
        }

        .option-btn.selected .dot {
            border-color: #764ba2;
            background: #764ba2;
        }

        .option-btn.selected .dot::after {
            content: '✓';
            color: #fff;
            font-size: 12px;
            font-weight: 700;
        }

        .weight-input-wrapper { position: relative; margin-bottom: 16px; }

        .weight-input {
            width: 100%;
            border: 2px solid #e8e8e8;
            border-radius: 12px;
            padding: 16px 60px 16px 18px;
            font-size: 24px;
            font-weight: 600;
            color: #333;
            outline: none;
            transition: border-color 0.3s ease;
            background: #fafafa;
        }

        .weight-input:focus { border-color: #764ba2; background: #fff; }

        .weight-unit {
            position: absolute;
            right: 18px;
            top: 50%;
            transform: translateY(-50%);
            font-size: 16px;
            color: #999;
            font-weight: 500;
        }

        .btn-row { display: flex; gap: 12px; margin-top: 28px; }

        .btn {
            flex: 1;
            border: none;
            border-radius: 12px;
            padding: 14px;
            font-size: 15px;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s ease;
        }

        .btn-back { background: #f0f0f0; color: #666; flex: 0.6; }
        .btn-back:hover { background: #e0e0e0; }

        .btn-next {
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: #fff;
        }

        .btn-next:hover {
            transform: translateY(-1px);
            box-shadow: 0 6px 20px rgba(118, 75, 162, 0.3);
        }

        .btn-next:disabled { opacity: 0.5; cursor: not-allowed; transform: none; box-shadow: none; }

        .btn-restart {
            background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
            color: #fff;
            margin-top: 20px;
        }

        .btn-restart:hover {
            transform: translateY(-1px);
            box-shadow: 0 6px 20px rgba(245, 87, 108, 0.3);
        }

        .result-card { text-align: center; padding: 10px 0; }
        .result-icon { font-size: 56px; margin-bottom: 12px; }
        .result-label { font-size: 14px; color: #888; margin-bottom: 8px; }

        .result-value {
            font-size: 48px;
            font-weight: 800;
            background: linear-gradient(135deg, #667eea 0%, #f5576c 100%);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
            line-height: 1.2;
        }

        .result-unit { font-size: 16px; color: #888; margin-top: 4px; }

        .result-formula {
            margin-top: 18px;
            padding: 14px 16px;
            background: linear-gradient(135deg, #e0e7ff 0%, #fce7f3 100%);
            border-radius: 12px;
            font-size: 16px;
            font-weight: 600;
            color: #555;
            text-align: center;
            letter-spacing: 0.5px;
        }

        .result-formula .num {
            color: #764ba2;
            font-weight: 700;
        }

        .result-formula .op {
            color: #f5576c;
            margin: 0 6px;
            font-weight: 700;
        }

        .result-details {
            margin-top: 22px;
            background: #f8f4ff;
            border-radius: 12px;
            padding: 16px;
            text-align: left;
        }

        .result-details .detail-row {
            display: flex;
            justify-content: space-between;
            padding: 6px 0;
            font-size: 14px;
            color: #555;
        }

        .result-details .detail-row:not(:last-child) { border-bottom: 1px solid #ede9f6; }
        .result-details .detail-label { color: #888; }
        .result-details .detail-value { font-weight: 600; color: #333; }

        .result-note {
            margin-top: 14px;
            padding: 10px 14px;
            background: #fff8f0;
            border-left: 3px solid #f5576c;
            border-radius: 6px;
            font-size: 13px;
            color: #666;
            line-height: 1.7;
            text-align: left;
        }

        .result-disclaimer {
            margin-top: 16px;
            font-size: 12px;
            color: #aaa;
            line-height: 1.6;
            text-align: center;
        }

        @media (max-width: 480px) {
            .container { border-radius: 16px; }
            .header { padding: 22px 20px; }
            .content { padding: 22px 20px 28px; }
            .pet-card .icon { font-size: 36px; }
        }