/* --- css/style.css (독립 스크롤 + 사이드바 통 스크롤) --- */

/* 1. 기본 설정 */
:root {
    --bg-body: #0a0a0a;
    --bg-sidebar: #111111;
    --bg-card: #161616;
    --text-main: #f0f0f0;
    --text-muted: #9ca3af;
    --accent-blue: #3b82f6;
    --accent-green: #10b981;
    --accent-purple: #8b5cf6;
    /* ▼▼▼ Phase 4용 안전 색상 추가 ▼▼▼ */
    --accent-orange: #f59e0b; 
    --border: 1px solid rgba(255, 255, 255, 0.08);
}

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

body {
    font-family: 'Inter', sans-serif;
    background: var(--bg-body);
    color: var(--text-main);
    display: flex;          /* 좌우 배치 */
    height: 100vh;          /* 화면 전체 높이 고정 */
    overflow: hidden;       /* 바디 전체 스크롤 방지 (각자 스크롤 하기 위함) */
}

a { text-decoration: none; color: inherit; }

/* --- 2. 사이드바 (통째로 스크롤) --- */
.sidebar {
    width: 360px;           /* 너비 고정 */
    flex-shrink: 0;         /* 줄어들지 않음 */
    background: var(--bg-sidebar);
    border-right: var(--border);
    display: flex;
    flex-direction: column;
    
    height: 100%;           /* 화면 높이 꽉 채움 */
    overflow-y: auto;       /* ★ 핵심: 내용이 넘치면 사이드바 전체가 스크롤됨 */
}

/* 스크롤바 디자인 (사이드바용) */
.sidebar::-webkit-scrollbar { width: 6px; }
.sidebar::-webkit-scrollbar-thumb { background: #333; border-radius: 3px; }
.sidebar::-webkit-scrollbar-track { background: var(--bg-sidebar); }

.sidebar-header { padding: 50px 40px 30px; text-align: center; border-bottom: var(--border); }
.avatar { width: 270px; height: 270px; border-radius: 20px; border: 3px solid #333; margin-bottom: 20px; object-fit: cover; box-shadow: 0 10px 20px rgba(0,0,0,0.5); }
.role-badge { font-size: 0.7rem; font-weight: 700; color: var(--accent-blue); background: rgba(59, 130, 246, 0.1); padding: 4px 10px; border-radius: 20px; }
.social-links { margin-top: 15px; display: flex; justify-content: center; gap: 15px; }
.social-links a { color: var(--text-muted); font-size: 1.2rem; transition: 0.2s; }
.social-links a:hover { color: #fff; transform: translateY(-2px); }

/* 메뉴 영역 */
.sidebar-menu { 
    padding: 30px 40px; 
    /* flex: 1; 제거 -> 그냥 흐름대로 배치 */
}
.menu-group { margin-bottom: 15px; }
.group-label { font-size: 0.7rem; color: #555; font-weight: 700; margin-bottom: 10px; display: block; letter-spacing: 1px; }

/* Collapsible Group Toggle */
.group-toggle {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: none;
    border: none;
    cursor: pointer;
    padding: 10px 15px;
    border-radius: 8px;
    transition: 0.2s;
    margin-bottom: 4px;
}
.group-toggle:hover { background: rgba(255,255,255,0.03); }
.group-toggle-right {
    display: flex;
    align-items: center;
    gap: 8px;
}
.toggle-arrow {
    color: #555;
    font-size: 0.65rem;
    transition: transform 0.3s ease;
}
.group-toggle .toggle-arrow { transform: rotate(0deg); }
.group-toggle.collapsed .toggle-arrow { transform: rotate(-90deg); }

/* Project badges */
.project-badge {
    font-size: 0.6rem;
    font-weight: 700;
    padding: 2px 7px;
    border-radius: 3px;
    letter-spacing: 0.5px;
}
.project-badge.main {
    background: rgba(59, 130, 246, 0.15);
    color: var(--accent-blue);
    border: 1px solid rgba(59, 130, 246, 0.25);
}
.project-badge.sub {
    background: rgba(255, 255, 255, 0.05);
    color: #666;
    border: 1px solid #333;
}

/* Submenu (collapsible content) */
.submenu {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.35s ease;
    padding-left: 6px;
    border-left: 2px solid transparent;
}
.submenu.open {
    max-height: 1200px; /* large enough to fit all items */
    border-left-color: rgba(59, 130, 246, 0.15);
}

/* Placeholder for upcoming projects */
.submenu-placeholder {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 15px;
    color: #444;
    font-size: 0.85rem;
    font-style: italic;
}
.submenu-placeholder i { font-size: 0.9rem; }

.btn-text {
    display: flex;          /* 내부 요소를 플렉스 박스로 설정 */
    flex-direction: column; /* 요소를 세로(위아래)로 배치 */
    align-items: flex-start;/* 왼쪽 정렬 */
    line-height: 1.2;       /* 줄 간격 조절 (너무 벌어지지 않게) */
}
.nav-btn {
    width: 100%; text-align: left; background: none; border: none; cursor: pointer;
    padding: 12px 15px; border-radius: 8px; margin-bottom:3px;
    color: var(--text-muted); display: flex; align-items: center; gap: 12px;
    transition: 0.2s;
}
.nav-btn:hover { background: rgba(255,255,255,0.05); color: #fff; }
.nav-btn.disabled-btn { cursor: default; opacity: 0.5; }
.nav-btn.disabled-btn:hover { background: none; color: var(--text-muted); }
.nav-btn.active { background: rgba(59, 130, 246, 0.1); color: var(--accent-blue); border-left: 3px solid var(--accent-blue); }
.nav-btn small { font-size: 0.75rem; opacity: 0.6; margin-top: 2px; }

/* 태그 스타일 */
.tech-tags { display: flex; flex-wrap: wrap; gap: 8px; }
.tech-tags span { font-size: 0.75rem; background: #222; padding: 4px 10px; border-radius: 4px; color: #888; border: 1px solid #333; }

/* --- 3. 메인 콘텐츠 영역 (독립 스크롤) --- */
.content-area {
    flex: 1;                /* 남은 너비 모두 차지 */
    height: 100%;           /* 화면 높이 꽉 채움 */
    overflow-y: auto;       /* ★ 핵심: 본문만 따로 스크롤됨 */
    background: var(--bg-body);
    position: relative;
    scroll-behavior: smooth;
}
/* 오른쪽 콘텐츠 영역 스크롤바 커스텀 */
.content-area::-webkit-scrollbar {
    width: 8px; /* 사이드바보다 조금 더 넓게 (가독성) */
}
.content-area::-webkit-scrollbar-track {
    background: var(--bg-body); 
}
.content-area::-webkit-scrollbar-thumb {
    background: #333; 
    border-radius: 4px;
    border: 1px solid var(--bg-body); /* 여백 느낌 주기 */
}
.content-area::-webkit-scrollbar-thumb:hover {
    background: #555; /* 호버 시 밝게 */
}

#app-container {
    max-width: 1000px; 
    margin: 0 auto;         /* 중앙 정렬 */
    padding: 80px 60px 100px; /* 상하좌우 여백 */
    min-height: 100%;       /* 최소 높이 확보 */
    animation: fadeIn 0.4s ease-out;
}

/* --- 4. 공통 요소 (유지) --- */
h1 { font-size: 2.5rem; margin-bottom: 10px; font-weight: 800; color: #fff; letter-spacing: -1px; }
.page-subtitle { color: var(--text-muted); font-size: 1.1rem; margin-bottom: 50px; line-height: 1.6; }

.feature-card, .phase-card, .info-box {
    background: var(--bg-card); border: var(--border); padding: 30px; border-radius: 12px; margin-bottom: 30px;
}
.feature-card h3 { font-size: 1.2rem; margin-bottom: 15px; color: #fff; display: flex; align-items: center; gap: 10px; }

/* 그리드 시스템 */
.grid-container { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 25px; margin-bottom: 40px; }

/* Tech Grid */
.tech-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(140px, 1fr)); gap: 15px; margin-top: 30px; }
.tech-item { background: rgba(255,255,255,0.03); border: 1px solid #333; border-radius: 8px; padding: 20px; text-align: center; transition: all 0.2s ease; display: flex; flex-direction: column; align-items: center; gap: 10px; }
.tech-item:hover { background: #1a1a1a; border-color: var(--accent-blue); transform: translateY(-3px); }
.tech-item i { font-size: 2rem; margin-bottom: 5px; color: #ccc; }
.tech-item span { font-size: 0.9rem; font-weight: 600; color: #eee; }
.tech-item small { font-size: 0.75rem; color: #777; font-family: 'JetBrains Mono', monospace; }

/* 코드 블록 */
pre { background: #0d0d0d; border: 1px solid #252525; padding: 20px; border-radius: 8px; overflow-x: auto; margin-top: 15px; }
code { font-family: 'JetBrains Mono', monospace; font-size: 0.85rem; color: #ccc; }
.keyword { color: #cc7832; }
.function { color: #ffc66d; }
.comment { color: #6a9955; }

/* Phase 3~5 mac-window 코드 블록용 syntax highlighting */
.kwd { color: #cc7832; }
.func { color: #ffc66d; }
.string { color: #6a8759; }
.num { color: #6897bb; }

/* mac-window 코드 블록 스타일 */
.mac-window {
    background: #0d0d0d;
    border: 1px solid #252525;
    border-radius: 8px;
    overflow: hidden;
    margin-top: 15px;
}
.mac-header {
    display: flex;
    align-items: center;
    padding: 10px 15px;
    background: #1a1a1a;
    border-bottom: 1px solid #252525;
}
.mac-dots {
    display: flex;
    gap: 6px;
    margin-right: 12px;
}
.mac-dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
}
.mac-red { background: #ff5f57; }
.mac-yellow { background: #febc2e; }
.mac-green { background: #28c840; }
.mac-title {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.75rem;
    color: #666;
}
.mac-body {
    padding: 20px;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.82rem;
    color: #ccc;
    line-height: 1.7;
    overflow-x: auto;
}

.divider { height: 1px; background: linear-gradient(to right, transparent, #333, transparent); margin: 60px 0; }

/* Footer (콘텐츠 영역 안에 포함됨) */
footer { margin-top: auto; padding: 60px 20px 40px; border-top: 1px solid rgba(255, 255, 255, 0.05); text-align: center; background: linear-gradient(to bottom, transparent, rgba(0,0,0,0.5)); }
.footer-quote { font-family: 'Times New Roman', Times, serif; font-style: italic; font-size: 1.1rem; color: #f0f0f0; margin-bottom: 10px; letter-spacing: 0.5px; opacity: 0.9; }
.footer-cite { font-size: 0.75rem; color: var(--accent-blue); font-weight: 600; margin-bottom: 25px; display: block; letter-spacing: 1px; text-transform: uppercase; }
.footer-copyright { font-size: 0.7rem; color: #555; font-family: 'Inter', sans-serif; }

/* Mobile */
.mobile-toggle { display: none; position: fixed; top: 20px; right: 20px; z-index: 200; background: #222; border: 1px solid #444; color: #fff; padding: 10px; border-radius: 6px; }

@media (max-width: 900px) {
    body { display: block; overflow: auto; height: auto; }
    .sidebar { width: 100%; height: auto; overflow: visible; border-right: none; border-bottom: var(--border); }
    .content-area { overflow: visible; height: auto; }
    #app-container { padding: 40px 20px; }
}

/* 유틸리티 (배지, 테이블 등) - 그대로 유지 */
.spec-badge { display: inline-block; background: #000; color: #888; font-family: 'JetBrains Mono', monospace; font-size: 0.75rem; padding: 4px 8px; border-radius: 4px; border: 1px solid #333; margin-top: 8px; }
.bom-table { width: 100%; border-collapse: collapse; font-size: 0.9rem; color: var(--text-muted); }
.bom-table th { text-align: left; padding: 15px; border-bottom: 2px solid #333; color: var(--text-main); font-weight: 700; }
.bom-table td { padding: 15px; border-bottom: 1px solid #222; }
.bom-table tr:hover td { background: rgba(255,255,255,0.02); color: #fff; }
.tag { font-size: 0.75rem; padding: 3px 8px; border-radius: 4px; font-weight: 700; }
.tag.main { background: rgba(16, 185, 129, 0.15); color: #10b981; border: 1px solid rgba(16, 185, 129, 0.2); }
.tag.sub { background: rgba(255, 255, 255, 0.05); color: #888; border: 1px solid #333; }



/* Tech Stack Grid (아이콘 박스 스타일) */
.tech-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr)); /* 반응형 그리드 */
    gap: 15px;
    margin-top: 30px;
}

.tech-item {
    background: rgba(255,255,255,0.03);
    border: 1px solid #333;
    border-radius: 8px;
    padding: 20px;
    text-align: center;
    transition: all 0.2s ease;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
}

.tech-item:hover {
    background: #1a1a1a;
    border-color: var(--accent-blue);
    transform: translateY(-3px);
}

.tech-item i { font-size: 2rem; margin-bottom: 5px; color: #ccc; }
.tech-item span { font-size: 0.9rem; font-weight: 600; color: #eee; }
.tech-item small { font-size: 0.75rem; color: #777; font-family: 'JetBrains Mono', monospace; }

/* 섹션 구분선 */
.divider {
    height: 1px;
    background: linear-gradient(to right, transparent, #333, transparent);
    margin: 60px 0;
}




/* 크몽 링크 컨테이너 미세 조정 */
.kmong-link {
    display: flex;
    align-items: center;
    justify-content: center;
    text-decoration: none;
}

/* K 로고 스타일링 */
.kmong-icon {
    font-family: 'Inter', sans-serif; /* 깔끔한 고딕체 */
    font-weight: 900;       /* 아주 두껍게 (로고처럼) */
    font-size: 1rem;      /* 크기 조정 */
    color: #111;            /* 글자색은 검정 (노란 배경 위니까) */
    background-color: #1d8f3b; /* 크몽 브랜드 컬러 (노란색) */
    width: 24px;            /* 동그라미 너비 */
    height: 24px;           /* 동그라미 높이 */
    border-radius: 50%;     /* 완벽한 원형 */
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s ease;
    padding-left: 1px;      /* 시각적 중앙 정렬 보정 */
}




/* 개발자 회고(Note) 스타일 */
.engineer-note {
    margin-top: 30px;
    padding: 20px;
    background: rgba(255, 255, 255, 0.05); /* 투명한 배경 */
    border-left: 4px solid var(--accent-blue); /* 포인트 컬러 */
    border-radius: 0 8px 8px 0;
    font-style: italic;
    position: relative;
}

/* Phase 2용 색상 변경 (초록색) */
.engineer-note.phase2 {
    border-left-color: var(--accent-green);
    background: rgba(16, 185, 129, 0.05);
}

.engineer-note h4 {
    font-style: normal;
    font-size: 0.85rem;
    color: #fff;
    margin-bottom: 8px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.engineer-note p {
    margin: 0;
    font-size: 0.9rem;
    color: #bbb;
    line-height: 1.6;
}


/* --- Roadmap Timeline Style --- */
.timeline-container {
    position: relative;
    max-width: 800px;
    margin: 40px auto;
    padding-left: 30px; /* 왼쪽 선 공간 확보 */
}

/* 수직 선 */
.timeline-container::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 2px;
    background: linear-gradient(to bottom, var(--accent-blue), var(--accent-green), var(--accent-purple), var(--accent-orange));
    opacity: 0.3;
}

.timeline-item {
    position: relative;
    margin-bottom: 60px;
    animation: fadeIn 0.5s ease-out;
}

/* 동그라미 마커 */
.timeline-marker {
    position: absolute;
    left: -36px; /* 선 위에 위치 */
    top: 0;
    width: 14px;
    height: 14px;
    border-radius: 50%;
    border: 2px solid #111;
}

.timeline-content {
    background: #1a1a1a;
    border: 1px solid #333;
    border-radius: 8px;
    padding: 25px;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.timeline-content:hover {
    transform: translateX(10px);
    box-shadow: 0 10px 30px rgba(0,0,0,0.5);
    background: #222;
}

.timeline-date {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.8rem;
    color: #666;
    margin-bottom: 5px;
    letter-spacing: 1px;
    font-weight: 700;
}




/* --- Engineering Notes Grid Style --- */
.notes-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 20px;
    margin-top: 30px;
}

.note-card {
    background: #1a1a1a;
    border: 1px solid #333;
    border-radius: 8px;
    padding: 25px;
    transition: transform 0.2s, border-color 0.2s;
    display: flex;
    flex-direction: column;
}

.note-card:hover {
    transform: translateY(-5px);
    border-color: var(--accent-blue);
    background: #202020;
}

.note-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
}

.note-cat {
    font-size: 0.7rem;
    font-weight: 700;
    text-transform: uppercase;
    color: var(--accent-blue);
    background: rgba(59, 130, 246, 0.1);
    padding: 3px 8px;
    border-radius: 4px;
}

.note-date {
    font-size: 0.75rem;
    color: #555;
    font-family: 'JetBrains Mono', monospace;
}

.note-card h3 {
    font-size: 1.1rem;
    color: #fff;
    margin-bottom: 10px;
    line-height: 1.4;
}

.note-summary {
    font-size: 0.9rem;
    color: #888;
    margin-bottom: 15px;
    line-height: 1.6;
    flex-grow: 1; /* 카드 높이 맞추기 */
}

.note-points {
    font-size: 0.85rem;
    color: #aaa;
    background: rgba(0,0,0,0.3);
    padding: 15px;
    border-radius: 6px;
    list-style: none;
    border-left: 2px solid #444;
}

.note-points li {
    margin-bottom: 6px;
}

.note-points li:last-child {
    margin-bottom: 0;
}

.note-points strong {
    color: #ccc;
    margin-right: 5px;
}

.note-footer {
    margin-top: 15px;
    padding-top: 15px;
    border-top: 1px solid #333;
    display: flex;
    align-items: center;
    gap: 8px;
    color: #666;
    font-size: 0.8rem;
}





/* --- Modal (팝업창) 스타일 --- */
.modal-overlay {
    display: none; /* 평소에는 숨김 */
    position: fixed;
    z-index: 9999;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.9); /* 배경 어둡게 */
    backdrop-filter: blur(5px); /* 배경 블러 효과 */
    justify-content: center;
    align-items: center;
    flex-direction: column;
}

.modal-content-container {
    position: relative;
    max-width: 90%;
    max-height: 85%;
    display: flex;
    justify-content: center;
    align-items: center;
}

.modal-media {
    max-width: 100%;
    max-height: 80vh;
    border-radius: 8px;
    box-shadow: 0 0 20px rgba(0,0,0,0.5);
    border: 1px solid #333;
}

.modal-close {
    position: absolute;
    top: 20px;
    right: 30px;
    color: #f1f1f1;
    font-size: 40px;
    font-weight: bold;
    cursor: pointer;
    transition: 0.3s;
    z-index: 10001;
}

.modal-close:hover { color: var(--accent-blue); }

/* 썸네일 스타일 (클릭 유도) */
.media-thumbnail {
    cursor: pointer;
    overflow: hidden;
    border-radius: 8px;
    border: 1px solid #333;
    position: relative;
    transition: transform 0.2s, border-color 0.2s;
    background: #000;
}

.media-thumbnail:hover {
    transform: scale(1.02);
    border-color: var(--accent-blue);
}

.media-thumbnail img, .media-thumbnail video {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
    opacity: 0.8;
    transition: opacity 0.2s;
}

.media-thumbnail:hover img, .media-thumbnail:hover video {
    opacity: 1;
}

/* 재생/확대 아이콘 오버레이 */
.thumbnail-overlay {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 2rem;
    color: #fff;
    opacity: 0.7;
    text-shadow: 0 2px 5px rgba(0,0,0,0.8);
    pointer-events: none; /* 아이콘이 클릭 방해 안 하게 */
}



/* --- [NEW] 사이드바 토글 (Full-width Mode) --- */

/* ─── 사이드바 트랜지션 ─── */
.sidebar {
    transition: width 0.3s ease;
    overflow-x: hidden;
    white-space: nowrap;
}

/* ─── 사이드바 상단: 토글 버튼 영역 ─── */
.sidebar-top {
    display: flex;
    justify-content: flex-end;
    align-items: center;
    padding: 12px 16px;
    flex-shrink: 0;
    border-bottom: var(--border);
}

/* ─── 토글 버튼 (사이드바 안에 위치) ─── */
.sidebar-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 30px;
    height: 30px;
    background: none;
    border: 1px solid rgba(255, 255, 255, 0.08);
    border-radius: 6px;
    color: var(--text-muted);
    cursor: pointer;
    transition: all 0.2s;
    font-size: 0.8rem;
    flex-shrink: 0;
}

.sidebar-toggle:hover {
    background: rgba(255, 255, 255, 0.06);
    color: #fff;
    border-color: rgba(255, 255, 255, 0.2);
}

/* ─── 접힌(collapsed) 상태: 슬림 레일 60px ─── */
.sidebar.collapsed {
    width: 60px;
}

.sidebar.collapsed .sidebar-top {
    justify-content: center;
    padding: 12px 0;
}

.sidebar.collapsed .sidebar-header {
    display: none;
}

.sidebar.collapsed .sidebar-menu {
    padding: 8px 6px;
}

.sidebar.collapsed .menu-group {
    margin-bottom: 4px;
}

.sidebar.collapsed .group-label {
    display: none;
}

.sidebar.collapsed .nav-btn {
    justify-content: center;
    padding: 12px;
    gap: 0;
}

.sidebar.collapsed .btn-text {
    display: none;
}

.sidebar.collapsed .nav-btn.active {
    border-left: none;
    border-radius: 8px;
}

.sidebar.collapsed .nav-btn i {
    font-size: 1.05rem;
}

/* ─── 모바일 전용 플로팅 버튼 ─── */
.mobile-menu-btn {
    display: none;
}

/* ─── 모바일 대응 ─── */
@media (max-width: 900px) {
    .sidebar {
        position: fixed;
        z-index: 999;
        height: 100%;
        width: 0;
        white-space: nowrap;
        overflow-x: hidden;
    }

    .sidebar.open {
        width: 85%;
        max-width: 360px;
    }

    /* 모바일에서는 collapsed 무시 (open/close만 사용) */
    .sidebar.collapsed {
        width: 0;
    }

    .sidebar.collapsed .sidebar-header {
        display: flex;
    }

    .sidebar.collapsed .sidebar-menu {
        padding: 30px 40px;
    }

    .sidebar.collapsed .group-label {
        display: block;
    }

    .sidebar.collapsed .nav-btn {
        justify-content: flex-start;
        padding: 12px 15px;
        gap: 12px;
    }

    .sidebar.collapsed .btn-text {
        display: flex;
    }

    .sidebar.collapsed .nav-btn.active {
        border-left: 3px solid var(--accent-blue);
    }

    .content-area {
        width: 100%;
    }

    .mobile-menu-btn {
        display: flex;
        align-items: center;
        justify-content: center;
        position: fixed;
        top: 16px;
        left: 16px;
        z-index: 1000;
        width: 40px;
        height: 40px;
        background: rgba(17, 17, 17, 0.9);
        backdrop-filter: blur(8px);
        border: 1px solid rgba(255, 255, 255, 0.1);
        border-radius: 8px;
        color: #fff;
        cursor: pointer;
        font-size: 0.9rem;
        transition: 0.2s;
    }

    .mobile-menu-btn:hover {
        background: var(--accent-blue);
        border-color: var(--accent-blue);
    }

    #app-container {
        padding-top: 70px;
    }
}


/* --- css/style.css 맨 아래에 추가하세요 --- */

/* TURNING POINT 버튼 전용 스타일 */
.nav-btn.special-warning {
    color: #888; /* 평소에는 다른 버튼과 비슷하게 */
    transition: all 0.2s ease;
}

/* 평소에 아이콘은 빨간색으로 포인트 */
.nav-btn.special-warning i {
    color: #ef4444; 
}

/* 마우스 올렸을 때 */
.nav-btn.special-warning:hover {
    background: rgba(239, 68, 68, 0.1);
    color: #fff;
}

/* ★ 핵심: 클릭되어 활성화(active) 되었을 때만 불이 켜짐 */
.nav-btn.special-warning.active {
    background: rgba(239, 68, 68, 0.15); /* 빨간 배경 */
    border-left: 3px solid #ef4444;      /* 빨간 테두리 */
    color: #ef4444;                      /* 글자색 빨강 */
}

/* 활성화 상태에서 제목 강조 */
.nav-btn.special-warning.active span {
    font-weight: bold;
}

/* Phase 3용 빨간색 노트 추가 */
.engineer-note.phase3 {
    border-left-color: #ef4444; /* 빨간색 테두리 */
    background: rgba(239, 68, 68, 0.05); /* 붉은 배경 은은하게 */
}


/* --- style.css 맨 아래에 추가 --- */

/* Phase 3 전용 스타일 (평소 상태) */
.nav-btn.special-highlight {
    color: var(--text-muted); /* 평소엔 회색 */
    transition: all 0.2s ease;
}

/* 마우스 올렸을 때 (Hover) */
.nav-btn.special-highlight:hover {
    background: rgba(239, 68, 68, 0.1); /* 연한 빨강 배경 */
    color: #fff; /* 글자는 흰색 */
}

/* ★ 클릭해서 활성화(Active) 되었을 때 */
.nav-btn.special-highlight.active {
    background: rgba(239, 68, 68, 0.15); /* 진한 빨강 배경 */
    border-left: 3px solid #ef4444;      /* 빨강 테두리 */
    color: #ef4444;                      /* 글자도 빨강 */
}

/* 활성화됐을 때 폰트 강조 */
.nav-btn.special-highlight.active span {
    font-weight: 700;
}

.nav-btn.special-highlight.active small {
    color: #ef4444; /* 설명 문구도 빨강 */
    opacity: 0.8;
}