:root {
    --primary-color: #6f42c1;
    --bg-mobile: #f8f9fa;
    --bg-pc: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

body {
    background: var(--bg-mobile);
    font-family: 'Noto Sans KR', sans-serif;
    margin: 0;
    height: 100vh;
    overflow: hidden;
}

/* === 메인 레이아웃 및 애니메이션 === */
.main-wrapper {
    height: 100vh;
    width: 100vw;
    overflow: hidden;
}

#et-answer::placeholder {
    opacity: 25%;
}

/* 전환 효과를 위한 설정 */
#sidebar-col {
    flex: 0 0 auto;
    width: calc(100% - 550px);
    opacity: 1;
    overflow: hidden;
    transition:
        width 0.3s ease 0.2s,
        opacity 0.3s ease 0.3s;
}

#app-col {
    flex: 0 0 auto;
    transition: all 0.6s cubic-bezier(0.25, 1, 0.5, 1);
}

.app-container {
    background-color: white;
    width: 100%;
    height: calc(100vh - 80px);
    border-radius: 30px;
    position: relative;
    overflow: hidden;
    display: flex;
    padding: 30px;
    flex-direction: column;
}

.game-mode .app-container {
    align-items: center;
    text-align: center;
}

/* 1. 왼쪽 사이드바 숨기기 */
.game-mode #sidebar-col {
    flex: 0 0 0% !important;
    width: 0 !important;
    padding: 0 !important;
    opacity: 0;
    overflow: hidden;
    transition:
        width 0.3s ease 0s,
        opacity 0.3s ease 0s;
}

/* 2. 앱 컨테이너 확장하기 */
.game-mode #app-col {
    width: 100% !important;
    max-width: 100% !important;
    transition: width 0.3s ease 0.3s;
}

/* 화면 전환 (페이드 효과) */
.screen {
    opacity: 0;
    transition: opacity 0.4s ease-in-out;
    display: none !important;
    height: 100%;
    width: 100%;
}

.screen.active {
    display: flex !important;
    opacity: 1;
}


/* 폰트 굵기 유틸리티 */
.fw-black {
    font-weight: 900;
}

/* 퀴즈 텍스트 */
.initial-text {
    font-size: 3.5rem;
    font-weight: 900;
    color: var(--primary-color);
    line-height: 1.2;
}

/* 버튼 호버 효과 */
.hover-scale {
    transition: transform 0.2s;
}

.hover-scale:hover {
    transform: scale(1.03);
}

/* 예문 박스 */
.example-box {
    font-family: 'Noto Sans KR', sans-serif;
    background-color: #e9ecef;
    padding: 15px;
    border-radius: 15px;
    margin-bottom: 10px;
    display: none;
    border-left: 5px solid var(--primary-color);
}

/* 오답 흔들림 효과 */
.shake-anim {
    animation: shake 0.4s;
    background-color: #fff0f0 !important;
}

.shake-anim-solution {
    animation: shake 0.4s;
    background-color: #f0fff4 !important;
}

@keyframes shake {

    0%,
    100% {
        transform: translateX(0);
    }

    25% {
        transform: translateX(-5px);
    }

    50% {
        transform: translateX(5px);
    }

    75% {
        transform: translateX(-5px);
    }
}


/* PC 환경 전용 스타일 */
@media (min-width: 992px) {
    body {
        background: var(--bg-pc);
    }

    .pc-sidebar {
        padding-right: 40px;
    }

    .glass-box {
        background: rgba(255, 255, 255, 0.1);
        backdrop-filter: blur(10px);
        border: 1px solid rgba(255, 255, 255, 0.2);
        border-radius: 15px;
    }

    #submit {
        width: 75%;
    }
}

/* 모바일 환경 전용 스타일 */
@media (max-width: 991.98px) {
    .app-container {
        height: 100vh;
        max-height: none;
        border-radius: 0;
        padding: 20px;
    }
    

    .game-mode #app-col {
        max-width: 100% !important;
    }

    #submit {
        width: 85%;
    }
}