/* ========================================
   테더 프리미엄 로그인 테마 - 완전 독립형 CSS
   ======================================== */

/* 리셋 & 기본 설정 */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html, body {
  width: 100%;
  height: 100%;
}

body {
  font-family: 'Open Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  font-size: 16px;
  line-height: 1.6;
  color: #2c3e50;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* 다크 테마 배경 */
body.bg-default {
  background: linear-gradient(135deg, #0a0a0a 0%, #1a0a0a 50%, #0f0f0f 100%) !important;
  position: relative;
  overflow-x: hidden;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

body.bg-default::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: radial-gradient(circle at 20% 50%, rgba(139, 31, 31, 0.05) 0%, transparent 50%),
              radial-gradient(circle at 80% 50%, rgba(196, 30, 58, 0.03) 0%, transparent 50%);
  z-index: 0;
  pointer-events: none;
}

/* 메인 콘텐츠 */
.main-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  position: relative;
  z-index: 1;
}

/* 네비게이션 바 */
.navbar {
  background: rgba(10, 10, 10, 0.98) !important;
  border-bottom: 1px solid rgba(196, 30, 58, 0.1);
  padding: 0 !important;
  backdrop-filter: blur(10px);
  box-shadow: 0 2px 20px rgba(0, 0, 0, 0.3);
  pointer-events: auto;
  z-index: 50;
}

.navbar > .container,
.navbar > .container-fluid {
  display: flex;
  align-items: center;
  justify-content: space-between !important;
  padding: 1.2rem 1.5rem !important;
  width: 100%;
  margin: 0 !important;
  pointer-events: auto;
}

.navbar-brand {
  font-size: 1.8rem;
  font-weight: 900;
  background: linear-gradient(135deg, #FF6B6B 0%, #C41E3A 50%, #8B1F1F 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: 2px;
  text-transform: uppercase;
  margin-right: 0;
  transition: all 0.3s ease;
  flex-shrink: 0;
  pointer-events: none;
}

/* Argon 로고 숨김 */
.navbar-collapse-header img,
.collapse-brand img {
  display: none !important;
}

/* 햄버거 메뉴 버튼 및 관련 요소 완전 숨김 */
.navbar-toggler,
.navbar-collapse-header {
  display: none !important;
}

.navbar-collapse {
  display: flex !important;
  align-items: center;
  justify-content: flex-end;
}

/* 네비게이션 항목 전체 숨김 */
.navbar-nav {
  display: flex !important;
  align-items: center;
  gap: 0.5rem;
}

.navbar-nav {
  pointer-events: auto;
}

.navbar-nav .nav-item {
  display: none !important;
}

/* 마지막 단계(language-switcher)만 표시 - 높은 specificity */
.navbar-nav > li.nav-item:last-child,
.navbar-nav > .nav-item:last-child,
li.nav-item:last-child,
.nav-item:last-child {
  display: flex !important;
  align-items: center;
  margin-left: auto;
  z-index: 1000;
  pointer-events: auto;
}

.language-switcher {
  position: relative;
  display: inline-block;
  z-index: 1001;
  pointer-events: auto;
}

.dropdown-toggle {
  pointer-events: auto !important;
  cursor: pointer !important;
  z-index: 1002 !important;
}

.language-menu {
  position: absolute;
  top: 110%;
  right: 0;
  margin-top: 8px;
  background-color: #ffffff;
  border: 1px solid #ddd;
  border-radius: 10px;
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.15);
  min-width: 150px;
  padding: 0.5rem 0;
  list-style: none;
  display: none;
  z-index: 1050;
}

.language-menu.show {
  display: flex !important;
  flex-direction: column;
  opacity: 1;
  visibility: visible;
  z-index: 1050 !important;
}

.language-item {
  display: block;
  padding: 0.65rem 1.2rem;
  text-decoration: none;
  color: #333333;
  border: none;
  background: none;
  width: 100%;
  text-align: left;
  transition: all 0.2s ease;
  cursor: pointer;
  font-size: 0.85rem;
}

.language-item:hover {
  background-color: #f8f9fa;
  color: #C41E3A;
  padding-left: 1.5rem;
}

.language-item.active {
  background-color: #fff3f3;
  color: #C41E3A;
  font-weight: 700;
}

.language-switcher .dropdown-toggle:hover,
.language-switcher .dropdown-toggle:focus {
  outline: none;
}

.language-switcher .dropdown-toggle::after {
  content: '▼';
  margin-left: 0.5rem;
  font-size: 0.6rem;
}

.language-switcher .dropdown-item {
  pointer-events: auto !important;
}

.ml-auto {
  margin-left: auto;
}

.container {
  max-width: 100%;
  width: 100%;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 1.5rem;
}

.px-4 {
  padding-left: 1.5rem;
  padding-right: 1.5rem;
}

/* 헤더 섹션 */
.header {
  background: linear-gradient(135deg, #C41E3A 0%, #8B1F1F 50%, #4A1515 100%) !important;
  padding: 6rem 0 !important;
  flex-shrink: 0;
  position: relative;
  overflow: hidden;
  box-shadow: 0 20px 60px rgba(196, 30, 58, 0.2);
}

.header::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.05'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
}

.header::after {
  content: '';
  position: absolute;
  bottom: -1px;
  left: 0;
  right: 0;
  height: 80px;
  background: #0a0a0a;
  clip-path: polygon(0 50%, 100% 0, 100% 100%, 0 100%);
}

.header-body {
  text-align: center;
  position: relative;
  z-index: 2;
}

.header-body h1 {
  font-size: 3.8rem;
  font-weight: 900;
  color: #fff;
  margin-bottom: 1.2rem;
  line-height: 1.1;
  letter-spacing: -0.5px;
  text-shadow: 0 5px 20px rgba(0, 0, 0, 0.3);
}

.header-body p {
  font-size: 1.3rem;
  color: rgba(255, 255, 255, 0.95);
  font-weight: 300;
  letter-spacing: 0.5px;
  text-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
}

.text-white {
  color: #fff !important;
}

.text-lead {
  font-size: 1.25rem;
}

.text-light {
  color: rgba(255, 255, 255, 0.9) !important;
}

/* 콘텐츠 컨테이너 */
.container.mt--8 {
  margin-top: -3rem;
  flex: 1;
  display: flex !important;
  align-items: center !important;
  justify-content: center !important;
  padding: 2rem 1.5rem 3rem 1.5rem;
  position: relative;
  z-index: 10;
  min-height: auto;
  max-width: 100%;
  width: 100%;
}

/* 행과 열 */
.row {
  display: flex !important;
  flex-wrap: wrap;
  margin: 0 auto !important;
  align-items: center !important;
  width: 100%;
  justify-content: center !important;
}

.row.justify-content-center {
  justify-content: center;
}

.row.mt-3 {
  margin-top: 1.5rem;
  width: 100%;
  justify-content: center;
  padding: 0 1rem;
}

.col-lg-5,
.col-md-6,
.col-md-7,
[class*='col-'] {
  flex: 1 1 auto;
  padding: 0 1rem;
  width: 100%;
}

.col-lg-5 {
  max-width: 580px !important;
  width: auto !important;
  margin: 0 auto !important;
  display: flex !important;
  flex-direction: column !important;
  justify-content: center !important;
  align-items: center !important;
}

.col-md-6 {
  max-width: 100%;
}

.col-md-7 {
  max-width: 100%;
}

.col-6 {
  max-width: 100%;
  flex: 0 0 auto;
  text-align: center;
  display: flex;
  justify-content: center;
}

.text-center {
  text-align: center;
  width: 100%;
  display: flex;
  justify-content: center;
  flex-direction: column;
}

.text-right {
  text-align: right;
}

/* 카드 */
.card {
  background: #fff;
  border: 1px solid rgba(196, 30, 58, 0.15);
  border-radius: 25px;
  box-shadow: 0 25px 80px rgba(0, 0, 0, 0.5), 0 0 1px rgba(196, 30, 58, 0.2);
  overflow: hidden;
  transition: all 0.35s cubic-bezier(0.4, 0, 0.2, 1);
  width: 100% !important;
  max-width: 580px !important;
  position: relative;
  backdrop-filter: blur(10px);
  margin: 0 auto !important;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, #FF6B6B 0%, #C41E3A 50%, #8B1F1F 100%);
  border-radius: 25px 25px 0 0;
}

.card:hover {
  box-shadow: 0 35px 100px rgba(196, 30, 58, 0.3), 0 0 2px rgba(196, 30, 58, 0.4);
  transform: translateY(-8px);
  border-color: rgba(196, 30, 58, 0.3);
}

.card.bg-secondary {
  background: #fff;
}

.card.shadow {
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.4);
}

.card.border-0 {
  border: none;
}

.card-body {
  padding: 2.5rem 3rem;
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

.card-body form {
  width: 100%;
  max-width: 500px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.card-header {
  background: transparent;
  border: none;
  padding: 1.5rem;
}

.px-lg-5 {
  padding-left: 3rem;
  padding-right: 3rem;
}

.py-lg-5 {
  padding-top: 3rem;
  padding-bottom: 3rem;
}

.pb-5 {
  padding-bottom: 3rem;
}

/* 폼 */
.form-group {
  margin-bottom: 1.8rem;
  margin-left: auto;
  margin-right: auto;
  width: 100%;
  max-width: 480px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.6rem;
}

.form-group .input-group-alternative {
  width: 100%;
  max-width: 480px;
  margin: 0 auto;
}

.form-group .id-check-button-group {
  width: auto;
}

.form-group.mb-3 {
  margin-bottom: 1.5rem !important;
  position: relative;
  z-index: 1;
}

.form-group.mb-3 .btn-outline-primary {
  position: absolute;
  right: 0.5rem;
  top: 50%;
  transform: translateY(-50%);
  padding: 0.5rem 1rem;
  font-size: 0.75rem;
  min-height: auto;
  white-space: nowrap;
  z-index: 10;
}

/* Override for input-group-append buttons - keep them inline, not absolute */
.input-group-append .btn-outline-primary {
  position: relative !important;
  right: auto !important;
  top: auto !important;
  transform: none !important;
  padding: 0.7rem 1.2rem !important;
  font-size: 0.8rem !important;
  min-height: 40px;
  min-width: 90px;
  display: inline-flex !important;
  align-items: center;
  justify-content: center;
  flex: 0 0 auto;
  white-space: nowrap;
  margin-left: 0.5rem;
}

.input-group {
  display: flex;
  align-items: center;
  position: relative;
  width: 100%;
  max-width: 100%;
  justify-content: center;
}

.input-group-alternative {
  display: flex;
  align-items: center;
  border: 2px solid #e5e5e5;
  border-radius: 18px;
  background: linear-gradient(135deg, #f9f9f9 0%, #ffffff 100%);
  transition: all 0.35s cubic-bezier(0.4, 0, 0.2, 1);
  min-height: 52px;
  overflow: visible;
  position: relative;
  width: 100%;
  max-width: 480px;
  margin: 0 auto;
  padding-right: 0;
}

.input-group-alternative::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 3px;
  background: linear-gradient(180deg, #FF6B6B 0%, #C41E3A 100%);
  opacity: 0;
  transition: opacity 0.3s;
}

.input-group-alternative:hover {
  border-color: #ddd;
  background: #fff;
  box-shadow: 0 5px 20px rgba(196, 30, 58, 0.1);
}

.input-group-alternative:focus-within {
  border-color: #C41E3A;
  background: #fff;
  box-shadow: 0 5px 25px rgba(196, 30, 58, 0.2);
}

.input-group-alternative:focus-within::before {
  opacity: 1;
}

.input-group.input-group-alternative.mb-3 {
  margin-bottom: 1rem;
}

.input-group-prepend {
  display: flex;
  align-items: center;
  flex-shrink: 0;
}

.input-group-append {
  display: flex;
  align-items: center;
  flex-shrink: 0;
}

.input-group-text {
  background: transparent;
  border: none;
  background: linear-gradient(135deg, #FF6B6B 0%, #C41E3A 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  padding: 1rem 1.8rem;
  font-size: 1.3rem;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
}

.form-control {
  flex: 1;
  border: none;
  background: transparent;
  padding: 1.2rem 0.8rem;
  font-size: 1rem;
  color: #2c3e50;
  outline: none;
  font-weight: 500;
  letter-spacing: 0.3px;
}

.input-group-append ~ .form-control,
.form-control:has(+ .input-group-append) {
  padding-right: 0.8rem;
}

.form-control::placeholder {
  color: #aaa;
  font-weight: 400;
}

.form-text {
  display: block;
  margin-top: 0.5rem;
  font-size: 0.85rem;
  color: #666;
}

.text-muted {
  color: #888 !important;
}

/* 버튼 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.7rem 1.5rem;
  font-size: 1rem;
  font-weight: 700;
  border: none;
  border-radius: 0.375rem;
  cursor: pointer;
  transition: all 0.35s cubic-bezier(0.4, 0, 0.2, 1);
  text-decoration: none;
  white-space: nowrap;
  user-select: none;
  min-height: 44px;
  text-transform: uppercase;
  letter-spacing: 0.8px;
}

.btn-primary {
  background: linear-gradient(135deg, #FF6B6B 0%, #C41E3A 50%, #8B1F1F 100%);
  color: #fff;
  padding: 1.1rem 3rem;
  font-size: 1.08rem;
  font-weight: 800;
  letter-spacing: 1.2px;
  border-radius: 18px;
  box-shadow: 0 15px 35px rgba(196, 30, 58, 0.35),
              inset 0 -2px 5px rgba(0, 0, 0, 0.1);
  width: 100%;
  min-height: 56px;
  border: 1px solid rgba(255, 255, 255, 0.1);
  position: relative;
  overflow: hidden;
  margin-top: 1.5rem;
}

.btn-primary::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
  transition: left 0.5s;
}

.btn-primary:hover {
  transform: translateY(-3px);
  box-shadow: 0 20px 50px rgba(196, 30, 58, 0.5),
              inset 0 -2px 5px rgba(0, 0, 0, 0.2);
  color: #fff;
}

.btn-primary:hover::before {
  left: 100%;
}

.btn-primary:active {
  transform: translateY(-1px);
}

.btn-primary.my-4 {
  margin-top: 2rem;
  margin-bottom: 1rem;
}

.btn-outline-primary {
  color: #C41E3A;
  border: 1px solid #C41E3A;
  background: transparent;
}

.btn-outline-primary:hover {
  background: #C41E3A;
  color: #fff;
}

.id-check-button-group {
  display: flex;
  justify-content: center;
  margin-top: 0;
  margin-bottom: 0;
  gap: 0.5rem;
  width: 100%;
  margin-left: auto;
  margin-right: auto;
  flex: 0 0 auto;
}

.form-control-id {
  flex: 1;
  border: none;
  background: transparent;
  padding: 1.2rem 0.8rem;
  font-size: 1rem;
  color: #2c3e50;
  outline: none;
  font-weight: 500;
  letter-spacing: 0.3px;
}

.form-control-id::placeholder {
  color: #aaa;
  font-weight: 400;
}

.btn-check-duplicate {
  display: inline-flex !important;
  align-items: center;
  justify-content: center;
  flex: 0 0 auto;
  padding: 0.75rem 1.8rem;
  min-width: 120px;
  height: 42px;
  margin-left: 0;
  background: linear-gradient(135deg, #FF6B6B 0%, #C41E3A 100%);
  color: #fff;
  border: none;
  border-radius: 8px;
  font-size: 0.85rem;
  font-weight: 700;
  white-space: nowrap;
  cursor: pointer;
  transition: all 0.3s;
  box-shadow: 0 5px 15px rgba(196, 30, 58, 0.2);
}

.btn-check-duplicate:hover {
  background: linear-gradient(135deg, #FF5252 0%, #B01929 100%);
  color: #fff;
  transform: translateY(-3px);
  box-shadow: 0 8px 25px rgba(196, 30, 58, 0.4);
}

.btn-check-duplicate:active {
  transform: translateY(-1px);
}

.btn-neutral {
  background: #f0f0f0;
  color: #333;
}

.btn-neutral:hover {
  background: #ddd;
}

.btn-icon {
  padding: 0.5rem 0.75rem;
}

.btn-wrapper {
  display: flex;
  gap: 1rem;
  justify-content: center;
}

/* 텍스트 콘텐츠 */
.text-center.text-muted.mb-4 small {
  font-size: 1.15rem;
  font-weight: 800;
  color: #2c3e50 !important;
  text-transform: uppercase;
  letter-spacing: 1px;
}

.row.mt-3 {
  margin-top: 1.5rem;
  width: 100%;
  justify-content: center;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
}

.row.mt-3 a {
  color: #C41E3A;
  text-decoration: none;
  font-weight: 600;
  font-size: 0.9rem;
  transition: all 0.3s;
  position: relative;
  display: block;
}

.row.mt-3 a::after {
  content: '';
  position: absolute;
  bottom: -3px;
  left: 0;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, #FF6B6B, #C41E3A);
  transition: width 0.3s;
}

.row.mt-3 a:hover {
  color: #8B1F1F;
}

.row.mt-3 a:hover::after {
  width: 100%;
}

.row.mt-3 a small {
  display: block;
  padding: 0.3rem 0;
}

a {
  color: #C41E3A;
  text-decoration: none;
  transition: all 0.3s;
  font-weight: 500;
}

a:hover {
  color: #8B1F1F;
}

/* 푸터 */
footer {
  background: rgba(10, 10, 10, 0.95);
  border-top: 1px solid rgba(196, 30, 58, 0.1);
  padding: 3rem 0;
  position: relative;
  z-index: 10;
  flex-shrink: 0;
}

footer.py-5 {
  padding-top: 3rem;
  padding-bottom: 3rem;
}

footer .copyright {
  color: rgba(255, 255, 255, 0.7) !important;
  text-align: center;
  font-weight: 500;
}

footer .copyright a {
  color: rgba(255, 255, 255, 0.9);
  font-weight: 700;
}

footer .copyright a:hover {
  color: #C41E3A;
}

footer .nav-footer {
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  list-style: none;
  margin-top: 1rem;
}

footer .nav-footer .nav-item a {
  color: rgba(255, 255, 255, 0.8);
  font-size: 0.85rem;
  font-weight: 500;
}

footer .nav-footer .nav-item a:hover {
  color: #C41E3A;
}

/* 체크박스 */
.custom-control {
  position: relative;
  display: flex;
  align-items: center;
  min-height: 1.8rem;
}

.custom-control-input {
  position: absolute;
  left: 0;
  z-index: -1;
  opacity: 0;
}

.custom-control-label {
  position: relative;
  margin-left: 2rem;
  margin-bottom: 0;
  color: #2c3e50;
  font-size: 0.9rem;
  cursor: pointer;
  font-weight: 500;
}

.custom-control-label::before {
  content: '';
  position: absolute;
  left: -2rem;
  top: 0.3rem;
  width: 1.4rem;
  height: 1.4rem;
  border: 2px solid #ddd;
  border-radius: 0.35rem;
  background: #fff;
  transition: all 0.35s;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.05);
}

.custom-control-input:checked ~ .custom-control-label::before {
  background: linear-gradient(135deg, #FF6B6B 0%, #C41E3A 100%);
  border-color: #C41E3A;
  box-shadow: 0 5px 15px rgba(196, 30, 58, 0.3);
}

.custom-control-label::after {
  content: '✓';
  position: absolute;
  left: -1.8rem;
  top: 0.15rem;
  width: 1.4rem;
  height: 1.4rem;
  color: #fff;
  opacity: 0;
  transition: opacity 0.3s;
  font-weight: 900;
  font-size: 0.9rem;
  display: flex;
  align-items: center;
  justify-content: center;
}

.custom-control-input:checked ~ .custom-control-label::after {
  opacity: 1;
}

/* 구분선 */
.separator {
  position: relative;
}

.separator-bottom.separator-skew {
  background: transparent !important;
  height: auto;
  margin-bottom: -2px;
}

.separator svg {
  width: 100%;
  height: auto;
  display: block;
}

.separator svg .fill-default {
  fill: #0a0a0a !important;
}

/* 반응형 디자인 */
@media (max-width: 768px) {
  .header {
    padding: 3.5rem 0 !important;
  }

  .header-body h1 {
    font-size: 2rem;
    margin-bottom: 0.8rem;
  }

  .header-body p {
    font-size: 1rem;
  }

  .col-lg-5 {
    max-width: 100%;
    flex: 0 0 auto;
  }

  .col-md-6,
  .col-md-7 {
    max-width: 100%;
    flex: 0 0 auto;
  }

  .card {
    max-width: 100%;
  }

  .card-body {
    padding: 2rem 2.5rem;
    align-items: center !important;
  }

  .btn-primary {
    padding: 0.95rem 2.5rem;
    font-size: 0.98rem;
    min-height: 50px;
  }

  .container.mt--8 {
    margin-top: -2.5rem;
    min-height: auto;
    padding: 2rem 1.5rem 3rem 1.5rem;
  }

  .form-group {
    margin-bottom: 1.5rem;
    width: 100%;
    max-width: 100%;
    display: flex !important;
    flex-direction: column !important;
    align-items: center !important;
  }

  .input-group-alternative {
    flex-wrap: nowrap;
    display: flex !important;
    width: 100%;
    max-width: calc(100% - 1.5rem) !important;
    margin: 0 auto !important;
  }

  .form-control {
    padding: 0.8rem 0.5rem !important;
    font-size: 0.95rem;
    flex: 1 1 auto;
  }

  .form-control-id {
    padding: 0.8rem 0.5rem !important;
    font-size: 0.95rem;
    flex: 1 1 auto;
  }

  .btn-check-duplicate {
    padding: 0.65rem 1.5rem !important;
    font-size: 0.8rem !important;
    min-width: 110px !important;
    height: 40px !important;
    margin-left: 0 !important;
    margin-top: 0.5rem !important;
  }

  .id-check-button-group {
    display: flex !important;
    justify-content: flex-start;
    margin-top: 0.8rem;
    margin-bottom: 0.5rem;
    width: 100%;
    max-width: calc(100% - 1.5rem) !important;
    margin-left: auto !important;
    margin-right: auto !important;
  }

  .input-group-append {
    display: flex !important;
    flex-shrink: 0;
    align-items: center;
    margin-left: 0.5rem;
  }

  .input-group-append .btn {
    padding: 0.6rem 1rem !important;
    font-size: 0.85rem !important;
    white-space: nowrap;
    flex: 0 0 auto;
    min-width: 95px;
    height: 40px;
    display: flex !important;
    align-items: center;
    justify-content: center;
  }

  .navbar-nav {
    flex-direction: column;
    gap: 0.25rem;
  }
}

@media (max-width: 480px) {
  .header {
    padding: 2.5rem 0 !important;
  }

  .header-body h1 {
    font-size: 1.8rem;
    margin-bottom: 0.5rem;
  }

  .header-body p {
    font-size: 0.95rem;
  }

  .navbar-brand {
    font-size: 1.3rem;
    letter-spacing: 1px;
  }

  .card {
    border-radius: 20px;
  }

  .card-body {
    padding: 1.2rem 1rem;
    align-items: center !important;
  }

  .form-group {
    margin-bottom: 1.3rem;
    width: 100%;
    max-width: 100%;
    display: flex !important;
    flex-direction: column !important;
    align-items: center !important;
  }

  .input-group-alternative {
    min-height: 48px;
    flex-wrap: nowrap;
    display: flex !important;
    width: calc(100% - 1.5rem) !important;
    max-width: 100% !important;
    margin: 0 auto !important;
  }

  .input-group-text {
    padding: 0.8rem 0.8rem;
    font-size: 1rem;
    flex-shrink: 0;
  }

  .form-control {
    padding: 0.8rem 0.5rem !important;
    font-size: 0.9rem;
    flex: 1 1 auto;
    min-width: 0;
  }

  .form-control-id {
    padding: 0.8rem 0.5rem !important;
    font-size: 0.9rem;
    flex: 1 1 auto;
    min-width: 0;
  }

  .btn-check-duplicate {
    padding: 0.55rem 1.2rem !important;
    font-size: 0.75rem !important;
    min-width: 85px !important;
    height: 36px !important;
    margin-left: 0 !important;
    margin-top: 0.5rem !important;
  }

  .id-check-button-group {
    display: flex !important;
    justify-content: flex-start;
    margin-top: 0.8rem;
    margin-bottom: 0.5rem;
    width: calc(100% - 1.5rem) !important;
    max-width: 100% !important;
    margin-left: auto !important;
    margin-right: auto !important;
  }

  .input-group-append {
    display: flex !important;
    flex-shrink: 0;
    align-items: center;
    margin-left: 0.4rem;
    gap: 0;
  }

  .input-group-append .btn {
    padding: 0.5rem 0.7rem !important;
    font-size: 0.75rem !important;
    white-space: nowrap;
    flex: 0 0 auto;
    min-width: 75px;
    height: 38px;
    display: flex !important;
    align-items: center;
    justify-content: center;
  }

  .btn-primary {
    padding: 0.85rem 1.8rem;
    font-size: 0.9rem;
    min-height: 48px;
    letter-spacing: 0.8px;
  }

  .row.mt-3 {
    margin: 1.2rem 0;
  }

  .row.mt-3 a {
    font-size: 0.85rem;
  }

  .container.mt--8 {
    margin-top: -2rem;
    min-height: auto;
    padding: 1.5rem;
  }

  .text-center.text-muted.mb-4 small {
    font-size: 1rem;
    letter-spacing: 0.8px;
  }
}

/* 모달 스타일 */
.modal {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 1050;
  display: none;
  width: 100%;
  height: 100%;
  overflow: hidden;
  outline: 0;
}

.modal.fade .modal-dialog {
  transition: transform 0.3s ease-out;
  transform: translate(0, -50px);
}

.modal.show .modal-dialog {
  transform: none;
}

.modal-dialog {
  position: relative;
  width: auto;
  margin: 0.5rem;
  pointer-events: none;
}

.modal-dialog-centered {
  display: flex;
  align-items: center;
  min-height: calc(100% - 1rem);
}

.modal-content {
  position: relative;
  display: flex;
  flex-direction: column;
  width: 100%;
  pointer-events: auto;
  background-color: #fff;
  background-clip: padding-box;
  border: 1px solid rgba(0, 0, 0, 0.2);
  border-radius: 0.5rem;
  outline: 0;
  box-shadow: 0 15px 35px rgba(50, 50, 93, 0.2), 0 5px 15px rgba(0, 0, 0, 0.17);
}

.modal-backdrop {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 1040;
  width: 100vw;
  height: 100vh;
  background-color: #000;
}

.modal-backdrop.fade {
  opacity: 0;
}

.modal-backdrop.show {
  opacity: 0.7;
}

.modal-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  padding: 1.25rem;
  border-bottom: 1px solid #e9ecef;
  border-top-left-radius: 0.5rem;
  border-top-right-radius: 0.5rem;
}

.modal-header.bg-warning {
  background: linear-gradient(135deg, #FF6B6B 0%, #C41E3A 50%, #8B1F1F 100%) !important;
  border-bottom: none;
}

.modal-title {
  margin-bottom: 0;
  line-height: 1.5;
  font-size: 1.25rem;
  font-weight: 600;
}

.modal-header .close {
  padding: 1rem;
  margin: -1rem -1rem -1rem auto;
  background-color: transparent;
  border: 0;
  font-size: 1.5rem;
  font-weight: 700;
  line-height: 1;
  color: #000;
  text-shadow: 0 1px 0 #fff;
  opacity: 0.5;
  cursor: pointer;
}

.modal-header .close:hover {
  opacity: 0.75;
}

.modal-header .close.text-white {
  color: #fff;
  text-shadow: none;
  opacity: 0.9;
}

.modal-body {
  position: relative;
  flex: 1 1 auto;
  padding: 1.5rem;
}

.modal-body p {
  margin-bottom: 0;
}

.modal-footer {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: flex-end;
  padding: 1rem;
  border-top: 1px solid #e9ecef;
  border-bottom-right-radius: 0.5rem;
  border-bottom-left-radius: 0.5rem;
}

.modal-footer.border-0 {
  border-top: none;
}

@media (min-width: 576px) {
  .modal-dialog {
    max-width: 500px;
    margin: 1.75rem auto;
  }

  .modal-dialog-centered {
    min-height: calc(100% - 3.5rem);
  }
}