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

:root {
  --primary: #4f46e5;
  --primary-hover: #4338ca;
  --bg-light: #ffffff;
  --bg-secondary-light: #f3f4f6;
  --bg-tertiary-light: #e5e7eb;
  --text-primary-light: #1f2937;
  --text-secondary-light: #6b7280;
  --border-light: #d1d5db;
  
  --bg-dark: #0f172a;
  --bg-secondary-dark: #1e293b;
  --bg-tertiary-dark: #334155;
  --text-primary-dark: #f1f5f9;
  --text-secondary-dark: #cbd5e1;
  --border-dark: #475569;
}

html, body {
  height: 100%;
}

body {
  background: var(--bg-light);
  color: var(--text-primary-light);
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Helvetica Neue', sans-serif;
  transition: background 0.3s, color 0.3s;
  display: flex;
  flex-direction: column;
}

body.dark-mode {
  background: var(--bg-dark);
  color: var(--text-primary-dark);
}

/* 헤더 */
header {
  background: var(--bg-secondary-light);
  border-bottom: 1px solid var(--border-light);
  padding: 1rem 0;
  transition: all 0.3s;
}

body.dark-mode header {
  background: var(--bg-secondary-dark);
  border-bottom-color: var(--border-dark);
}

.header-wrapper {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.header-logo {
  font-size: 20px;
  font-weight: 600;
  text-decoration: none;
  color: var(--text-primary-light);
}

body.dark-mode .header-logo {
  color: var(--text-primary-dark);
}

.header-nav {
  display: flex;
  gap: 2rem;
  align-items: center;
}

.header-nav a {
  text-decoration: none;
  color: var(--text-secondary-light);
  font-size: 14px;
  font-weight: 500;
  transition: color 0.3s;
}

body.dark-mode .header-nav a {
  color: var(--text-secondary-dark);
}

.header-nav a:hover {
  color: var(--primary);
}

.dark-toggle {
  background: var(--bg-light);
  border: 1px solid var(--border-light);
  border-radius: 8px;
  padding: 0.5rem 0.75rem;
  cursor: pointer;
  font-size: 18px;
  transition: all 0.3s;
}

body.dark-mode .dark-toggle {
  background: var(--bg-tertiary-dark);
  border-color: var(--border-dark);
}

.dark-toggle:hover {
  background: var(--bg-secondary-light);
}

body.dark-mode .dark-toggle:hover {
  background: var(--bg-secondary-dark);
}

/* 메인 콘텐츠 */
main {
  flex: 1;
  max-width: 900px;
  width: 100%;
  margin: 0 auto;
  padding: 2rem 1.5rem;
}

.container {
  width: 100%;
}

/* 섹션 */
.section {
  margin-bottom: 3rem;
}

.section-title {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 1rem;
  color: var(--text-primary-light);
}

body.dark-mode .section-title {
  color: var(--text-primary-dark);
}

.description {
  font-size: 14px;
  color: var(--text-secondary-light);
  margin-bottom: 2rem;
  line-height: 1.6;
}

body.dark-mode .description {
  color: var(--text-secondary-dark);
}

/* 폼 */
.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.form-row.full {
  grid-template-columns: 1fr;
}

@media (max-width: 600px) {
  .form-row {
    grid-template-columns: 1fr;
  }
}

.form-group {
  display: flex;
  flex-direction: column;
}

.form-label {
  font-size: 14px;
  font-weight: 500;
  margin-bottom: 0.5rem;
  color: var(--text-secondary-light);
}

body.dark-mode .form-label {
  color: var(--text-secondary-dark);
}

.input-wrapper {
  position: relative;
}

input[type="number"],
input[type="text"],
select {
  width: 100%;
  padding: 0.75rem;
  border: 2px solid var(--border-light);
  border-radius: 12px;
  font-size: 16px;
  background: var(--bg-light);
  color: var(--text-primary-light);
  transition: all 0.3s;
}

body.dark-mode input[type="number"],
body.dark-mode input[type="text"],
body.dark-mode select {
  background: var(--bg-secondary-dark);
  color: var(--text-primary-dark);
  border-color: var(--border-dark);
}

input[type="number"]:focus,
input[type="text"]:focus,
select:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

body.dark-mode input[type="number"]:focus,
body.dark-mode input[type="text"]:focus,
body.dark-mode select:focus {
  box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.2);
}

.unit-label {
  position: absolute;
  right: 12px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 12px;
  color: var(--text-secondary-light);
  pointer-events: none;
}

body.dark-mode .unit-label {
  color: var(--text-secondary-dark);
}

/* 버튼 */
.button-group {
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: 1rem;
  margin-top: 2rem;
}

@media (max-width: 600px) {
  .button-group {
    grid-template-columns: 1fr;
  }
}

button {
  padding: 0.75rem 1.5rem;
  border: none;
  border-radius: 12px;
  font-size: 16px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.3s;
}

.btn-calculate {
  background: var(--primary);
  color: white;
}

.btn-calculate:hover {
  background: var(--primary-hover);
}

.btn-calculate:disabled {
  background: #9ca3af;
  cursor: not-allowed;
}

.btn-reset {
  background: var(--bg-secondary-light);
  color: var(--text-primary-light);
  border: 1px solid var(--border-light);
}

body.dark-mode .btn-reset {
  background: var(--bg-secondary-dark);
  color: var(--text-primary-dark);
  border-color: var(--border-dark);
}

.btn-reset:hover {
  background: var(--bg-tertiary-light);
}

body.dark-mode .btn-reset:hover {
  background: var(--bg-tertiary-dark);
}

/* 결과 섹션 */
.result-section {
  margin-top: 2rem;
  display: none;
}

.result-section.active {
  display: block;
}

.result-box {
  background: var(--bg-secondary-light);
  padding: 1.5rem;
  border-radius: 12px;
  margin-bottom: 1.5rem;
}

body.dark-mode .result-box {
  background: var(--bg-secondary-dark);
}

.result-bmi {
  font-size: 32px;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.result-category {
  font-size: 18px;
  margin-bottom: 1rem;
}

.result-range {
  font-size: 14px;
  color: var(--text-secondary-light);
  line-height: 1.6;
}

body.dark-mode .result-range {
  color: var(--text-secondary-dark);
}

.bmi-gauge {
  margin-top: 2rem;
  padding: 1.5rem 0;
}

.gauge-bar {
  width: 100%;
  height: 48px;
  background: linear-gradient(90deg, 
    #3b82f6 0%, 
    #3b82f6 25%, 
    #10b981 25%, 
    #10b981 50%, 
    #f59e0b 50%, 
    #f59e0b 75%, 
    #ef4444 75%, 
    #ef4444 100%);
  border-radius: 24px;
  overflow: hidden;
  margin-bottom: 2rem;
  position: relative;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
  display: flex;
  align-items: center;
}

body.dark-mode .gauge-bar {
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.4);
}

.gauge-labels-overlay {
  position: absolute;
  width: 100%;
  height: 100%;
  display: flex;
  z-index: 10;
}

.label-item {
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-weight: 700;
  font-size: 14px;
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

.gauge-fill {
  height: 100%;
  border-radius: 24px;
  position: absolute;
  left: 0;
  top: 0;
  background: transparent;
  transition: width 0.6s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.gauge-fill::after {
  content: '';
  position: absolute;
  right: -14px;
  top: 50%;
  transform: translateY(-50%);
  width: 0;
  height: 0;
  border-left: 14px solid rgba(0, 0, 0, 0.15);
  border-top: 16px solid transparent;
  border-bottom: 16px solid transparent;
}

.gauge-labels {
  display: flex;
  justify-content: space-between;
  font-size: 14px;
  font-weight: 700;
  color: var(--text-primary-light);
  margin-top: 1.5rem;
  padding: 0 8px;
}

body.dark-mode .gauge-labels {
  color: var(--text-primary-dark);
}

.gauge-labels span {
  flex: 1;
  text-align: center;
  padding: 0 0.5rem;
}

.gauge-labels span:nth-child(1) {
  color: #3b82f6;
}

.gauge-labels span:nth-child(2) {
  color: #10b981;
}

.gauge-labels span:nth-child(3) {
  color: #f59e0b;
}

.gauge-labels span:nth-child(4) {
  color: #ef4444;
}

.category-underweight { color: #3b82f6; }
.category-normal { color: #10b981; }
.category-overweight { color: #f59e0b; }
.category-obese { color: #ef4444; }

/* 카드 그리드 */
.card-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
  margin-top: 1.5rem;
}

@media (max-width: 768px) {
  .card-grid {
    grid-template-columns: 1fr;
  }
}

.card {
  background: var(--bg-secondary-light);
  border: 2px solid var(--border-light);
  border-radius: 16px;
  padding: 1.5rem;
  transition: all 0.3s;
}

body.dark-mode .card {
  background: var(--bg-secondary-dark);
  border-color: var(--border-dark);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 16px rgba(79, 70, 229, 0.1);
}

body.dark-mode .card:hover {
  box-shadow: 0 8px 16px rgba(79, 70, 229, 0.2);
}

.card-icon {
  width: 48px;
  height: 48px;
  background: linear-gradient(135deg, #4f46e5 0%, #7c3aed 100%);
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 24px;
  margin-bottom: 1rem;
}

.card-title {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 0.5rem;
  color: var(--primary);
}

.card-description {
  font-size: 14px;
  color: var(--text-secondary-light);
  line-height: 1.6;
}

body.dark-mode .card-description {
  color: var(--text-secondary-dark);
}

.card-grid.full {
  grid-template-columns: 1fr;
}

.card-grid.full .card {
  display: grid;
  grid-template-columns: 60px 1fr;
  gap: 1.5rem;
  align-items: flex-start;
}

.card-grid.full .card-icon {
  margin-bottom: 0;
}
.loading {
  display: none;
  text-align: center;
  margin: 1rem 0;
}

.loading.active {
  display: block;
}

.spinner {
  display: inline-block;
  width: 20px;
  height: 20px;
  border: 3px solid var(--border-light);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

body.dark-mode .spinner {
  border-color: var(--border-dark);
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* 에러 메시지 */
.error-message {
  background: #fee2e2;
  color: #991b1b;
  padding: 1rem;
  border-radius: 8px;
  margin-bottom: 1rem;
  display: none;
}

body.dark-mode .error-message {
  background: rgba(239, 68, 68, 0.1);
  color: #fca5a5;
}

.error-message.active {
  display: block;
}

/* 푸터 */
footer {
  background: var(--bg-secondary-light);
  border-top: 1px solid var(--border-light);
  margin-top: auto;
  padding: 2rem 0;
  transition: all 0.3s;
}

body.dark-mode footer {
  background: var(--bg-secondary-dark);
  border-top-color: var(--border-dark);
}

.footer-wrapper {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 1.5rem;
  text-align: center;
  font-size: 14px;
  color: var(--text-secondary-light);
}

body.dark-mode .footer-wrapper {
  color: var(--text-secondary-dark);
}

.footer-wrapper p {
  margin-bottom: 0.5rem;
}

/* 게시판 리스트 */
.board-list {
  background: var(--bg-secondary-light);
  border-radius: 12px;
  overflow: hidden;
  margin-bottom: 2rem;
}

body.dark-mode .board-list {
  background: var(--bg-secondary-dark);
}

.board-header {
  display: grid;
  grid-template-columns: 60px 1fr 60px 100px;
  gap: 1rem;
  padding: 1rem;
  background: var(--primary);
  color: white;
  font-weight: 600;
  font-size: 14px;
}

.board-col-num {
  text-align: center;
}

.board-col-title {
  text-align: left;
}

.board-col-views {
  text-align: center;
}

.board-col-date {
  text-align: center;
}

.board-item {
  display: grid;
  grid-template-columns: 60px 1fr 60px 100px;
  gap: 1rem;
  padding: 1.25rem;
  border-bottom: 1px solid var(--border-light);
  text-decoration: none;
  color: var(--text-primary-light);
  transition: all 0.3s;
}

body.dark-mode .board-item {
  border-bottom-color: var(--border-dark);
  color: var(--text-primary-dark);
}

@media (max-width: 1024px) {
  .board-header, .board-item {
    grid-template-columns: 1fr;
    gap: 0.5rem;
    padding: 1rem;
  }
  
  .board-header {
    padding: 0.75rem;
    font-size: 12px;
  }
  
  /* 데스크탑 헤더 숨기기 */
  .board-col-num::before,
  .board-col-views::before,
  .board-col-date::before {
    content: '';
    display: none;
  }
}

@media (max-width: 768px) {
  .board-header {
    display: none; /* 모바일에서 헤더 완전히 숨기기 */
  }
  
  .board-item {
    grid-template-columns: 1fr;
    gap: 0.5rem;
    padding: 1rem;
    background: var(--bg-secondary-light);
    border-radius: 8px;
    border-bottom: none;
    margin-bottom: 0.75rem;
  }
  
  body.dark-mode .board-item {
    background: var(--bg-secondary-dark);
  }
  
  /* 모바일에서 데이터 레이블 표시 */
  .board-col-num {
    font-size: 12px;
    color: var(--text-secondary-light);
    text-align: left;
  }
  
  body.dark-mode .board-col-num {
    color: var(--text-secondary-dark);
  }
  
  .board-col-title {
    font-weight: 600;
    font-size: 15px;
    line-height: 1.4;
  }
  
  .board-col-views {
    display: grid;
    grid-template-columns: auto auto;
    gap: 0.5rem;
    font-size: 12px;
    color: var(--text-secondary-light);
    text-align: left;
  }
  
  body.dark-mode .board-col-views {
    color: var(--text-secondary-dark);
  }
  
  .board-col-date {
    font-size: 12px;
    color: var(--text-secondary-light);
    text-align: left;
  }
  
  body.dark-mode .board-col-date {
    color: var(--text-secondary-dark);
  }
}

body.dark-mode .board-item {
  border-bottom-color: var(--border-dark);
  color: var(--text-primary-dark);
}

.board-item:last-child {
  border-bottom: none;
}

.board-item:hover {
  background: var(--bg-tertiary-light);
}

body.dark-mode .board-item:hover {
  background: var(--bg-tertiary-dark);
}

.board-title {
  display: block;
  font-weight: 500;
  line-height: 1.5;
  color: var(--text-primary-light);
}

body.dark-mode .board-title {
  color: var(--text-primary-dark);
}

.board-item:hover .board-title {
  color: var(--primary);
}

/* 페이지네이션 */
.pagination {
  display: flex;
  justify-content: center;
  gap: 0.5rem;
  margin-top: 2rem;
}

.page-prev, .page-next, .page-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border: 1px solid var(--border-light);
  border-radius: 8px;
  background: var(--bg-light);
  color: var(--text-primary-light);
  text-decoration: none;
  font-weight: 500;
  transition: all 0.3s;
  cursor: pointer;
}

body.dark-mode .page-prev,
body.dark-mode .page-next,
body.dark-mode .page-num {
  background: var(--bg-secondary-dark);
  border-color: var(--border-dark);
  color: var(--text-primary-dark);
}

.page-prev:hover, .page-next:hover, .page-num:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.page-num.active {
  background: var(--primary);
  color: white;
  border-color: var(--primary);
}

/* 게시물 상세보기 */
.post-header {
  margin-bottom: 2rem;
  padding-bottom: 1.5rem;
  border-bottom: 2px solid var(--border-light);
}

body.dark-mode .post-header {
  border-bottom-color: var(--border-dark);
}

.post-title-wrapper {
  margin-bottom: 1rem;
}

.post-title {
  font-size: 28px;
  font-weight: 600;
  line-height: 1.5;
  color: var(--text-primary-light);
  margin: 0;
}

body.dark-mode .post-title {
  color: var(--text-primary-dark);
}

.post-meta {
  display: flex;
  gap: 1.5rem;
  font-size: 14px;
  color: var(--text-secondary-light);
}

body.dark-mode .post-meta {
  color: var(--text-secondary-dark);
}

.post-content {
  margin-bottom: 2rem;
}

.post-image {
  width: 100%;
  max-height: 500px;
  border-radius: 12px;
  overflow: hidden;
  margin-bottom: 2rem;
}

.post-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.post-body {
  font-size: 16px;
  line-height: 1.8;
  color: var(--text-primary-light);
}

body.dark-mode .post-body {
  color: var(--text-primary-dark);
}

.post-body p {
  margin-bottom: 1.5rem;
}

.post-body h3 {
  font-size: 20px;
  font-weight: 600;
  margin: 2rem 0 1rem 0;
  color: var(--primary);
}

.post-body img {
  max-width: 100%;
  height: auto;
  border-radius: 8px;
  margin: 1.5rem 0;
}

.post-body a {
  color: var(--primary);
  text-decoration: none;
}

.post-body a:hover {
  text-decoration: underline;
}

.post-footer {
  padding: 2rem 0;
  border-top: 1px solid var(--border-light);
  border-bottom: 1px solid var(--border-light);
}

body.dark-mode .post-footer {
  border-color: var(--border-dark);
}

.post-buttons {
  display: flex;
  gap: 1rem;
}

.btn-back {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  background: var(--bg-secondary-light);
  color: var(--text-primary-light);
  border: 1px solid var(--border-light);
  border-radius: 8px;
  text-decoration: none;
  font-weight: 500;
  transition: all 0.3s;
}

body.dark-mode .btn-back {
  background: var(--bg-secondary-dark);
  color: var(--text-primary-dark);
  border-color: var(--border-dark);
}

.btn-back:hover {
  background: var(--primary);
  color: white;
  border-color: var(--primary);
}

/* 댓글 섹션 */
.comments-section {
  margin-top: 3rem;
}

.comments-title {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 1.5rem;
  color: var(--text-primary-light);
}

body.dark-mode .comments-title {
  color: var(--text-primary-dark);
}

.comment-form {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-bottom: 2rem;
}

.comment-input {
  width: 100%;
  min-height: 100px;
  padding: 1rem;
  border: 1px solid var(--border-light);
  border-radius: 8px;
  background: var(--bg-light);
  color: var(--text-primary-light);
  font-family: inherit;
  font-size: 14px;
  resize: vertical;
}

body.dark-mode .comment-input {
  background: var(--bg-secondary-dark);
  border-color: var(--border-dark);
  color: var(--text-primary-dark);
}

.comment-input:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

.btn-comment-submit {
  align-self: flex-end;
  padding: 0.75rem 2rem;
  background: var(--primary);
  color: white;
  border: none;
  border-radius: 8px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.3s;
}

.btn-comment-submit:hover {
  background: var(--primary-hover);
}

.comments-list {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.comment-item {
  padding: 1.5rem;
  background: var(--bg-secondary-light);
  border-radius: 8px;
}

body.dark-mode .comment-item {
  background: var(--bg-secondary-dark);
}

.comment-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.75rem;
}

.comment-author {
  font-weight: 600;
  color: var(--text-primary-light);
}

body.dark-mode .comment-author {
  color: var(--text-primary-dark);
}

.comment-date {
  font-size: 13px;
  color: var(--text-secondary-light);
}

body.dark-mode .comment-date {
  color: var(--text-secondary-dark);
}

.comment-body {
  font-size: 14px;
  line-height: 1.6;
  color: var(--text-primary-light);
}

body.dark-mode .comment-body {
  color: var(--text-primary-dark);
}

/* 반응형 */
@media (max-width: 768px) {
  .board-header, .board-item {
    grid-template-columns: 1fr;
  }
  
  .board-col-date {
    text-align: left;
  }
  
  .post-title {
    font-size: 22px;
  }
  
  .comment-header {
    flex-direction: column;
    align-items: flex-start;
  }
}

/* 반응형 */
@media (max-width: 600px) {
  main {
    padding: 1rem 1rem;
  }

  .header-nav {
    gap: 1rem;
  }

  .header-nav a {
    font-size: 13px;
  }
}