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

        :root {
            --primary: #ff922b;
            --primary-dark: #e8590c;
            --secondary: #f76707;
            --accent-pink: #FFB6D9;
            --accent-blue: #B4E7FF;
            --accent-orange: #FFE4B5;
            --text-dark: #2d3748;
            --text-light: #718096;
            --white: #ffffff;
        }

        #introScreen {
            font-family: 'Outfit', 'Noto Sans KR', -apple-system, BlinkMacSystemFont, sans-serif;
            min-height: 100vh;
            overflow-x: hidden;
            background: linear-gradient(135deg, #ffecd2 0%, #fcb69f 50%, #fbc2eb 100%);
            position: relative;
        }

        /* 배경 애니메이션 */
        .bg-shapes {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            pointer-events: none;
            overflow: hidden;
            z-index: 0;
        }

        .shape {
            position: absolute;
            border-radius: 50%;
            opacity: 0.15;
            animation: float 20s infinite ease-in-out;
        }

        .shape:nth-child(1) {
            width: 400px;
            height: 400px;
            background: var(--accent-pink);
            top: -100px;
            left: -100px;
            animation-delay: 0s;
        }

        .shape:nth-child(2) {
            width: 300px;
            height: 300px;
            background: var(--accent-blue);
            top: 50%;
            right: -80px;
            animation-delay: -5s;
        }

        .shape:nth-child(3) {
            width: 250px;
            height: 250px;
            background: var(--accent-orange);
            bottom: -50px;
            left: 20%;
            animation-delay: -10s;
        }

        .shape:nth-child(4) {
            width: 200px;
            height: 200px;
            background: var(--white);
            top: 30%;
            left: 10%;
            animation-delay: -15s;
        }

        @keyframes float {
            0%, 100% { transform: translate(0, 0) rotate(0deg); }
            25% { transform: translate(30px, -30px) rotate(5deg); }
            50% { transform: translate(-20px, 20px) rotate(-5deg); }
            75% { transform: translate(20px, 10px) rotate(3deg); }
        }

        /* 메인 컨테이너 */
        .main-container {
            position: relative;
            z-index: 1;
            min-height: 100vh;
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            padding: 40px 20px;
        }

        /* 카드 */
        .card {
            background: rgba(255, 255, 255, 0.95);
            backdrop-filter: blur(20px);
            border-radius: 32px;
            padding: 60px 50px;
            max-width: 520px;
            width: 100%;
            box-shadow: 
                0 25px 80px rgba(0, 0, 0, 0.15),
                0 10px 30px rgba(255, 146, 43, 0.2);
            text-align: center;
            animation: cardEntry 0.8s ease-out;
        }

        @keyframes cardEntry {
            from {
                opacity: 0;
                transform: translateY(40px) scale(0.95);
            }
            to {
                opacity: 1;
                transform: translateY(0) scale(1);
            }
        }

        /* 로고 영역 */
        .logo-section {
            margin-bottom: 30px;
        }

        .logo-img {
            max-width: min(100%, 560px);
            height: auto;
        }

        /* 언어 선택 */
        .lang-section {
            margin-top: 20px;
        }

        .lang-label {
            font-size: 0.95em;
            color: var(--text-light);
            margin-bottom: 20px;
            font-weight: 500;
        }

        .lang-buttons {
            display: flex;
            gap: 16px;
            justify-content: center;
        }

        .lang-btn {
            flex: 1;
            max-width: 160px;
            padding: 18px 24px;
            border: 2.5px solid transparent;
            border-radius: 16px;
            font-size: 1.1em;
            font-weight: 700;
            cursor: pointer;
            transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
            text-align: center;
            font-family: inherit;
            white-space: nowrap;
            background: linear-gradient(135deg, #fff3e0 0%, #ffe0b2 100%);
            color: #5c4a3a;
            box-shadow: 0 4px 15px rgba(255,146,43,0.15);
        }

        .lang-btn:hover {
            transform: translateY(-4px);
            box-shadow: 0 8px 25px rgba(255,146,43,0.3);
            background: linear-gradient(135deg, #ffe0b2 0%, #ffcc80 100%);
        }

        /* 브라우저 감지 추천 언어 — 진한 오렌지 */
        .lang-btn.lang-recommended {
            background: linear-gradient(135deg, #ff922b 0%, #f76707 100%);
            color: white;
            box-shadow: 0 6px 20px rgba(255,146,43,0.35);
            transform: scale(1.05);
        }

        .lang-btn.lang-recommended:hover {
            transform: scale(1.05) translateY(-4px);
            box-shadow: 0 10px 30px rgba(255,146,43,0.45);
        }

        /* 인트로 소개글 */
        .intro-desc {
            text-align: center;
            font-size: 1em;
            font-weight: 500;
            color: #8b7355;
            letter-spacing: 0.05em;
            margin: -10px 0 20px;
        }

        .lang-btn:active {
            transform: translateY(-2px);
        }

        .flag {
            font-size: 1.3em;
        }

        /* 교안 링크 */
        .curriculum-link {
            margin-top: 20px;
            text-align: center;
        }

        .curriculum-link a {
            display: inline-flex;
            align-items: center;
            gap: 6px;
            padding: 10px 24px;
            background: rgba(255, 255, 255, 0.2);
            backdrop-filter: blur(10px);
            border: 1.5px solid rgba(255, 255, 255, 0.4);
            border-radius: 20px;
            color: white;
            text-decoration: none;
            font-size: 0.9em;
            font-weight: 600;
            transition: all 0.3s;
        }

        .curriculum-link a:hover {
            background: rgba(255, 255, 255, 0.35);
            transform: translateY(-2px);
            box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
        }

        /* 푸터 */
        .footer {
            margin-top: 16px;
            color: rgba(255, 255, 255, 0.7);
            font-size: 0.8em;
            font-weight: 400;
        }

        .footer a {
            color: rgba(255, 255, 255, 0.9);
            text-decoration: none;
            font-weight: 500;
            transition: color 0.2s;
        }

        .footer a:hover {
            color: var(--white);
        }

        /* 반응형 */
        @media (max-width: 540px) {
            .card {
                padding: 40px 30px;
                border-radius: 24px;
            }

            .lang-buttons {
                flex-direction: column;
                gap: 12px;
            }

            .lang-btn {
                max-width: 100%;
                padding: 16px 24px;
            }
        }