/* [Root Variables] */
:root { 
    --bg-color: #ffffff; 
    --text-color: #333333; 
    --header-bg: #ffffff; 
    --border-color: #eeeeee; 
    --card-bg: #f9f9f9; 
    --footer-bg: #f1f1f1; 
    --accent-color: #007bff; 
    --content-text: #555555;
    --timeline-line: #e0e0e0;
}

body.dark-mode { 
    --bg-color: #121212; 
    --text-color: #e0e0e0; 
    --header-bg: #1e1e1e; 
    --border-color: #333333; 
    --card-bg: #1e1e1e; 
    --footer-bg: #0a0a0a; 
    --accent-color: #3391ff; 
    --content-text: #b0b0b0;
    --timeline-line: #444444;
}

/* [Reset & Base] */
* { margin: 0; padding: 0; box-sizing: border-box; }
body { 
    font-family: 'Pretendard', sans-serif; 
    background-color: var(--bg-color); 
    color: var(--text-color); 
    transition: background 0.2s, color 0.2s; 
    overflow-x: hidden; 
}
a { text-decoration: none; color: inherit; }

/* [Header] */
header { 
    display: flex; 
    justify-content: space-between; 
    align-items: center; 
    padding: 0 5%; 
    height: 80px; 
    background: var(--header-bg); 
    border-bottom: 1px solid var(--border-color); 
    position: sticky; 
    top: 0; 
    z-index: 1000; 
}
.header-left { display: flex; align-items: center; gap: 40px; }
.logo-link img { height: 40px; width: auto; display: block; }
.nav-links { display: flex; list-style: none; gap: 30px; }
.nav-links a { font-weight: 600; font-size: 15px; line-height: 80px; display: block; color: var(--text-color); }
.nav-links a:hover { color: var(--accent-color); }

/* [Controls & Toggle] */
.controls { display: flex; align-items: center; gap: 25px; }
.lang-dropdown { position: relative; cursor: pointer; font-size: 14px; font-weight: 600; padding: 10px 0; }
.lang-menu { 
    display: none; 
    position: absolute; 
    right: 0; 
    top: 40px; 
    background: var(--header-bg); 
    border: 1px solid var(--border-color); 
    border-radius: 4px; 
    list-style: none; 
    min-width: 100px; 
    box-shadow: 0 4px 6px rgba(0,0,0,0.1); 
    padding: 5px 0; 
    z-index: 1001; 
}
.lang-dropdown:hover .lang-menu { display: block; }
.lang-menu li { padding: 10px 15px; color: var(--text-color); }
.lang-menu li:hover { background: var(--border-color); }

.switch { position: relative; width: 46px; height: 24px; display: inline-block; }
.switch input { opacity: 0; width: 0; height: 0; }
.slider { 
    position: absolute; cursor: pointer; top: 0; left: 0; right: 0; bottom: 0; 
    background-color: #ccc; transition: .4s; border-radius: 34px; 
}
.slider:before { 
    position: absolute; content: ""; height: 18px; width: 18px; 
    left: 3px; bottom: 3px; background-color: white; transition: .4s; border-radius: 50%; 
}
input:checked + .slider { background-color: #4cd964; }
input:checked + .slider:before { transform: translateX(22px); }

/* [Footer] */
footer { 
    padding: 50px 5%; 
    text-align: center; 
    border-top: 1px solid var(--border-color); 
    background: var(--bg-color); 
}
.footer-sns { margin: 20px 0; display: flex; justify-content: center; align-items: center; gap: 30px; }
.x-logo-img { height: 32px; width: auto; transition: 0.3s; opacity: 0.7; filter: brightness(0); }
body.dark-mode .x-logo-img { filter: brightness(0) invert(1); }
.footer-sns a:hover .x-logo-img { opacity: 1; transform: scale(1.1); filter: none; }

.footer-sns .fa-youtube { font-size: 34px; color: var(--text-color); opacity: 0.7; transition: 0.3s; }
.footer-sns a:hover .fa-youtube { opacity: 1; color: #ff0000; transform: scale(1.1); }

.footer-email { margin-top: 15px; font-size: 14px; font-weight: 500; }
.footer-email a:hover { color: var(--accent-color); }

.footer-legal { 
    margin-top: 20px; 
    display: flex; 
    justify-content: center; 
    gap: 20px; 
    font-size: 13px; 
}
.footer-legal a:hover { 
    opacity: 1; 
    color: var(--accent-color); 
    text-decoration: underline; 
}

.footer-copyright { margin-top: 15px; font-size: 12px; font-weight: 500; opacity: 0.7; }

/* [Reveal Animation] */
.reveal { opacity: 0; transform: translateY(30px); transition: all 0.8s ease-out; }
.reveal.active { opacity: 1; transform: translateY(0); }

/* [Mobile Navigation & Floating Button] */
@media (max-width: 850px) {
    /* 상단 내비게이션 숨김 */
    header .nav-links { display: none !important; }

    /* 하단 고정바 */
    .mobile-bottom-nav {
        display: flex !important;
        position: fixed !important;
        bottom: 15px;
        left: 50%;
        transform: translateX(-50%);
        width: 92%;
        max-width: 450px;
        height: 65px;
        background: var(--header-bg);
        border: 1px solid var(--border-color);
        border-radius: 40px;
        box-shadow: 0 10px 30px rgba(0,0,0,0.2);
        z-index: 9999;
        justify-content: space-around;
        align-items: center;
        padding: 0 5px;
    }

    /* 탭 기본 스타일 (파란 빛 제거 버전) */
    .nav-item {
        flex: 1;
        display: flex;
        flex-direction: column;
        align-items: center;
        text-decoration: none;
        color: var(--text-color);
        gap: 4px;
        opacity: 0.8;
        transition: 0.3s;
    }

    .nav-item i { font-size: 1.25rem; }
    
    .nav-item span {
        font-size: 0.65rem;
        font-weight: 600;
        white-space: nowrap;
    }

    /* active 클래스 강조 효과 제거 (텍스트 색상은 유지) */
    .nav-item.active {
        opacity: 1;
        color: var(--text-color) !important;
        font-weight: 700;
    }

    /* 2차창작활동 가이드라인 버튼 */
    .report-floating-btn {
        display: flex !important;
        position: fixed !important;
        bottom: 90px;
        right: 20px;
        background: var(--header-bg);
        border: 1px solid var(--border-color);
        border-radius: 8px;
        padding: 10px 16px;
        font-size: 0.8rem;
        font-weight: 600;
        text-decoration: none;
        color: var(--text-color);
        box-shadow: 0 4px 15px rgba(0,0,0,0.15);
        align-items: center;
        gap: 8px;
        z-index: 9998;
    }
}

/* PC 버전에서는 하단 바와 버튼 숨김 */
@media (min-width: 851px) {
    .mobile-bottom-nav, .report-floating-btn { display: none; }
}