:root {
  --bg-color: #f8f9fa;
  --text-color: #212529;
  --nav-bg: #ffffff;
  --nav-text: #212529;
  --card-bg: #ffffff;
  --card-shadow: rgba(0, 0, 0, 0.08);
  --accent-color: #007bff;
}

body.dark-mode {
  --bg-color: #121212;
  --text-color: #e9ecef;
  --nav-bg: #1e1f22;
  --nav-text: #ffffff;
  --card-bg: #1e1f22;
  --card-shadow: rgba(0, 0, 0, 0.4);
}

body {
  background-color: var(--bg-color);
  color: var(--text-color);
  font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  line-height: 1.6;
  margin: 0;
  transition: background-color 0.3s, color 0.3s;
}

/* 네비게이션 바 */
.navbar {
  position: sticky;
  top: 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 15px 50px;
  background-color: var(--nav-bg);
  box-shadow: 0 2px 10px var(--card-shadow);
  z-index: 1000;
  transition: background-color 0.3s;
}

.nav-logo {
  font-size: 1.5rem;
  font-weight: 800;
}

.nav-links {
  display: flex;
  list-style: none;
  gap: 30px;
  margin: 0;
  padding: 0;
}

.nav-links a {
  text-decoration: none;
  color: var(--text-color);
  font-weight: 600;
  font-size: 0.95rem;
  transition: color 0.3s;
}

.nav-links a:hover {
  color: var(--accent-color);
}

.container {
  max-width: 900px;
  margin: 0 auto;
  padding: 60px 20px;
}

/* 헤더 & 섹션 제목 */
.site-header {
  text-align: center;
  margin-bottom: 80px;
}

h1 { font-size: 3rem; margin-bottom: 20px; }
.subtitle { font-size: 1.2rem; opacity: 0.8; margin-bottom: 30px; }
.about-content { font-size: 1.1rem; color: var(--text-color); opacity: 0.9; max-width: 700px; margin: 0 auto; }

.section-title {
  text-align: center;
  font-size: 2rem;
  margin-bottom: 40px;
}

/* 곰돌이 그리드 */
.bear-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 30px;
  margin-bottom: 100px;
}

.bear-card {
  background-color: var(--card-bg);
  border-radius: 20px;
  padding: 30px;
  box-shadow: 0 10px 30px var(--card-shadow);
  transition: transform 0.3s;
  border: 1px solid rgba(0,0,0,0.05);
  display: flex;
  flex-direction: column;
  height: 100%;
}

body.dark-mode .bear-card { border-color: rgba(255,255,255,0.05); }

.bear-card:hover { transform: translateY(-10px); }
.bear-emoji { font-size: 3.5rem; margin-bottom: 20px; text-align: center; transition: transform 0.2s ease; }
.bear-card h3 { margin-bottom: 15px; font-size: 1.4rem; text-align: center; }
.bear-card p { font-size: 1rem; opacity: 0.85; text-align: justify; margin-bottom: 25px; flex-grow: 1; }

.emoji-btn {
  display: block;
  width: 100%;
  padding: 12px;
  background-color: var(--accent-color);
  color: white;
  border: none;
  border-radius: 12px;
  cursor: pointer;
  font-weight: 600;
  transition: opacity 0.3s;
  margin-top: auto;
}

.emoji-btn:hover {
  opacity: 0.8;
}

/* 연구 일지(칼럼) 스타일 */
.journal-list {
  display: flex;
  flex-direction: column;
  gap: 30px;
}

.journal-item {
  background-color: var(--card-bg);
  padding: 30px;
  border-radius: 15px;
  box-shadow: 0 5px 15px var(--card-shadow);
}

.journal-item h3 { margin-bottom: 15px; color: var(--accent-color); }
.journal-item p { line-height: 1.8; opacity: 0.9; }

/* FAQ 스타일 */
.faq-grid {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.faq-item {
  border-bottom: 1px solid rgba(0,0,0,0.1);
  padding-bottom: 20px;
}

body.dark-mode .faq-item { border-color: rgba(255,255,255,0.1); }
.faq-item h4 { font-size: 1.1rem; margin-bottom: 10px; color: var(--accent-color); }
.faq-item p { opacity: 0.8; }

.section {
  margin-bottom: 100px;
  scroll-margin-top: 100px;
}

.bg-light {
  background-color: rgba(0,0,0,0.02);
  padding: 60px 20px;
  margin-left: -20px;
  margin-right: -20px;
  border-radius: 30px;
}

/* 폼 섹션 */
.contact-section {
  background-color: var(--card-bg);
  padding: 50px;
  border-radius: 25px;
  box-shadow: 0 10px 30px var(--card-shadow);
  margin-bottom: 80px;
}

.contact-form { max-width: 600px; margin: 0 auto; display: flex; flex-direction: column; gap: 20px; }
.form-group label { font-weight: 700; margin-bottom: 8px; display: block; }
.form-group input, .form-group textarea {
  width: 100%; padding: 12px; border-radius: 12px; border: 1px solid rgba(0,0,0,0.1);
  background-color: var(--bg-color); color: var(--text-color); font-family: inherit;
}

.submit-btn {
  padding: 15px; background-color: var(--accent-color); color: white; border: none;
  border-radius: 12px; font-size: 1.1rem; font-weight: 700; cursor: pointer; transition: 0.3s;
}

.submit-btn:hover { background-color: #0056b3; transform: scale(1.02); }

/* 푸터 (Privacy Policy 전용) */
.site-footer {
  margin-top: 100px;
  padding: 60px 0 20px;
  border-top: 1px solid rgba(0,0,0,0.1);
  font-size: 0.9rem;
  opacity: 0.8;
}

body.dark-mode .site-footer { border-color: rgba(255,255,255,0.1); }

.footer-content h3 { margin-bottom: 20px; }
.copyright { margin-top: 40px; text-align: center; font-weight: 600; }

/* 테마 토글 버튼 스타일 수정 */
#theme-toggle {
  padding: 8px 16px; border-radius: 20px; cursor: pointer; border: 1px solid var(--accent-color);
  background: transparent; color: var(--text-color); font-weight: 600;
}

@media (max-width: 768px) {
  .navbar { padding: 15px 20px; flex-direction: column; gap: 15px; }
  .nav-links { gap: 15px; font-size: 0.85rem; }
}