:root {
    --brand: #1a1a2e;
    --brand-2: #2b2f36;
    --accent: #0f4c81;
    --accent-light: #e8f4ff;
    --bg: #f8f9fb;
    --text: #1a1a1a;
    --muted: #6b7280;
    --line: #e5e7eb;
    --btn: linear-gradient(135deg, #0f4c81 0%, #1a73e8 100%);
    --btn-hover: linear-gradient(135deg, #0d3f6b 0%, #1557b0 100%);
    --card-shadow: 0 2px 8px rgba(0,0,0,0.04);
    --card-hover: 0 4px 16px rgba(0,0,0,0.08);
  }

  * { box-sizing: border-box; }

  /* 접근성: 스크린 리더를 위한 건너뛰기 링크 */
  .skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    background: #0f4c81;
    color: white;
    padding: 8px 16px;
    text-decoration: none;
    border-radius: 0 0 4px 0;
    z-index: 1000;
    font-weight: 700;
  }

  .skip-link:focus {
    top: 0;
  }

  body {
    font-family: -apple-system, BlinkMacSystemFont, "Apple SD Gothic Neo", "Malgun Gothic", "Segoe UI", Roboto, sans-serif;
    margin: 0;
    padding: 0;
    background: var(--bg);
    color: var(--text);
    padding-bottom: 120px;
    -webkit-text-size-adjust: 100%;
    line-height: 1.6;
  }

  /* 교육 목적 상단 배너 */
  .education-banner {
    background: linear-gradient(135deg, #10b981 0%, #059669 100%);
    color: #fff;
    text-align: center;
    padding: 10px 20px;
    font-size: 13px;
    font-weight: 700;
    letter-spacing: -0.3px;
    box-shadow: 0 2px 8px rgba(16,185,129,0.3);
    position: sticky;
    top: 0;
    z-index: 100;
  }

  .education-banner-icon {
    display: inline-block;
    margin-right: 6px;
  }

  /* 무료 서비스 표시 배지 */
  .free-badge {
    display: inline-block;
    background: #fbbf24;
    color: #78350f;
    font-size: 11px;
    padding: 4px 10px;
    border-radius: 999px;
    font-weight: 800;
    margin-left: 8px;
    border: 2px solid #f59e0b;
  }

  .container {
    max-width: 540px;
    margin: 0 auto;
    background: #fff;
    min-height: 100vh;
    box-shadow: 0 0 40px rgba(0,0,0,0.06);
    position: relative;
  }

  /* 상단 헤더 */
  .site-header {
    background: linear-gradient(135deg, #0f4c81 0%, #1a73e8 100%);
    padding: 24px 20px 20px 20px;
    position: sticky;
    top: 0;
    z-index: 10;
    box-shadow: 0 2px 12px rgba(15,76,129,0.15);
  }

  .brand-wrap {
    display: flex;
    flex-direction: column;
    gap: 6px;
    align-items: center;
    text-align: center;
  }

  .brand-name {
    font-weight: 900;
    color: #fff;
    font-size: 22px;
    letter-spacing: -0.5px;
    text-shadow: 0 2px 4px rgba(0,0,0,0.1);
  }

  .brand-sub {
    font-size: 13px;
    color: rgba(255,255,255,0.9);
    font-weight: 500;
  }

  .pill {
    background: rgba(255,255,255,0.2);
    backdrop-filter: blur(10px);
    color: #fff;
    font-size: 11px;
    padding: 6px 14px;
    border-radius: 999px;
    border: 1px solid rgba(255,255,255,0.3);
    white-space: nowrap;
    margin-top: 8px;
    display: inline-block;
    font-weight: 600;
  }

  /* 히어로 영역 */
  .hero-card {
    background: linear-gradient(180deg, #fff 0%, #f8f9fb 100%);
    padding: 36px 20px 32px 20px;
    text-align: center;
    border-bottom: 1px solid var(--line);
  }

  .icon {
    width: 88px;
    height: 88px;
    background: linear-gradient(135deg, var(--accent-light) 0%, #fff 100%);
    border-radius: 24px;
    margin: 0 auto 18px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 42px;
    border: 2px solid var(--accent-light);
    box-shadow: 0 4px 16px rgba(15,76,129,0.1);
  }

  .title {
    font-size: 24px;
    font-weight: 900;
    margin-bottom: 12px;
    line-height: 1.3;
    letter-spacing: -0.5px;
    color: var(--brand);
  }

  .meta {
    font-size: 13px;
    color: var(--muted);
    margin-bottom: 20px;
    line-height: 1.5;
  }

  .desc {
    font-size: 15px;
    color: #374151;
    line-height: 1.7;
    max-width: 400px;
    margin: 0 auto;
  }

  /* 학습 커리큘럼 영역 */
  .learning-system-section {
    padding: 32px 20px;
    background: linear-gradient(135deg, #f0f7ff 0%, #e8f4ff 100%);
    border-bottom: 1px solid var(--line);
  }

  .learning-system-title {
    font-size: 20px;
    font-weight: 900;
    color: var(--brand);
    margin: 0 0 16px 0;
    text-align: center;
    letter-spacing: -0.4px;
  }

  .learning-system-subtitle {
    font-size: 14px;
    color: var(--muted);
    text-align: center;
    margin-bottom: 24px;
    line-height: 1.6;
  }

  .learning-image-wrapper {
    background: #fff;
    border-radius: 16px;
    padding: 16px;
    box-shadow: 0 4px 20px rgba(15,76,129,0.12);
    margin-bottom: 16px;
  }

  .learning-image {
    width: 100%;
    height: auto;
    display: block;
    border-radius: 12px;
  }

  .learning-highlights {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
    margin-top: 20px;
  }

  .highlight-item {
    background: #fff;
    padding: 14px;
    border-radius: 12px;
    text-align: center;
    border: 1px solid rgba(15,76,129,0.1);
    box-shadow: var(--card-shadow);
  }

  .highlight-number {
    font-size: 20px;
    font-weight: 900;
    color: var(--accent);
    margin-bottom: 4px;
  }

  .highlight-text {
    font-size: 12px;
    color: var(--muted);
    font-weight: 600;
  }

  /* 상단 안내 문구 */
  .top-disclaimer {
    margin: 20px 20px 0 20px;
    border: 2px solid #fef3c7;
    background: #fffbeb;
    padding: 16px;
    border-radius: 12px;
    color: #92400e;
    line-height: 1.6;
    text-align: left;
    font-size: 13px;
    word-break: keep-all;
  }
  .top-disclaimer strong { color: #78350f; font-weight: 800; }

  /* 가입 안내 모듈 */
  .join-reminder {
    margin: 20px 20px;
    border: 2px solid #10b981;
    background: linear-gradient(135deg, #d1fae5 0%, #a7f3d0 100%);
    padding: 20px;
    border-radius: 16px;
    text-align: center;
    box-shadow: 0 4px 20px rgba(16,185,129,0.2);
    animation: pulse 2s ease-in-out infinite;
  }

  .join-reminder-icon {
    font-size: 36px;
    margin-bottom: 10px;
    display: block;
  }

  .join-reminder-title {
    font-size: 18px;
    font-weight: 900;
    color: #065f46;
    margin-bottom: 12px;
    letter-spacing: -0.3px;
  }

  .join-reminder-content {
    font-size: 15px;
    color: #047857;
    line-height: 1.7;
    margin-bottom: 14px;
  }

  .join-reminder-keyword {
    display: inline-block;
    background: #fff;
    color: #059669;
    font-size: 20px;
    font-weight: 900;
    padding: 12px 24px;
    border-radius: 12px;
    border: 2px solid #10b981;
    box-shadow: 0 2px 8px rgba(16,185,129,0.3);
    letter-spacing: 2px;
    margin: 8px 0;
  }

  .join-reminder-note {
    font-size: 13px;
    color: #047857;
    margin-top: 12px;
    font-weight: 600;
  }

  .join-reminder-disclaimer {
    margin-top: 16px;
    padding-top: 16px;
    border-top: 2px solid rgba(16,185,129,0.3);
    font-size: 12px;
    color: #065f46;
    line-height: 1.8;
    text-align: left;
    background: rgba(255,255,255,0.7);
    padding: 14px;
    border-radius: 8px;
  }

  .join-reminder-disclaimer strong {
    color: #047857;
    font-weight: 800;
  }

  @keyframes pulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.02); }
  }

  /* 공통 섹션 */
  .section { padding: 28px 20px 16px 20px; }

  .section-title {
    font-size: 18px;
    color: var(--brand);
    margin: 0 0 16px 0;
    font-weight: 900;
    letter-spacing: -0.3px;
  }

  .feature-grid { display: grid; gap: 12px; }

  .feature-card {
    background: #fff;
    border: 1px solid var(--line);
    border-radius: 14px;
    padding: 20px;
    box-shadow: var(--card-shadow);
    transition: all 0.3s ease;
  }

  .feature-card:hover {
    box-shadow: var(--card-hover);
    transform: translateY(-2px);
  }

  .feature-icon { font-size: 28px; margin-bottom: 12px; }

  .feature-title {
    font-size: 16px;
    font-weight: 800;
    color: var(--brand);
    margin-bottom: 8px;
  }

  .feature-desc {
    font-size: 14px;
    color: var(--muted);
    line-height: 1.6;
  }

  /* 게시글 카드 */
  .post {
    background: #fff;
    border: 1px solid var(--line);
    border-radius: 14px;
    padding: 18px;
    margin-bottom: 12px;
    text-align: left;
    box-shadow: var(--card-shadow);
    transition: all 0.3s ease;
  }

  .post:hover {
    box-shadow: var(--card-hover);
    transform: translateY(-2px);
  }

  .post-head {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 14px;
  }

  .avatar {
    width: 42px;
    height: 42px;
    background: linear-gradient(135deg, var(--accent) 0%, #1a73e8 100%);
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 900;
    font-size: 16px;
    flex-shrink: 0;
  }

  .post-name {
    font-size: 14px;
    font-weight: 800;
    color: var(--brand);
    margin: 0 0 2px 0;
  }

  .post-note {
    font-size: 12px;
    color: var(--muted);
    margin: 0;
  }

  .post-body {
    font-size: 15px;
    line-height: 1.7;
    color: #374151;
    word-break: break-word;
  }

  .tags {
    margin-top: 14px;
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
  }

  .tag {
    font-size: 12px;
    color: var(--accent);
    background: var(--accent-light);
    border: 1px solid rgba(15,76,129,0.2);
    border-radius: 999px;
    padding: 6px 12px;
    font-weight: 600;
  }

  /* 하단 고정 버튼 영역 */
  .fixed-bottom {
    position: fixed;
    bottom: 0;
    left: 0;
    width: 100%;
    background: #fff;
    padding: 14px 0;
    padding-bottom: calc(14px + env(safe-area-inset-bottom));
    border-top: 1px solid var(--line);
    display: flex;
    flex-direction: column;
    align-items: center;
    z-index: 99;
    box-shadow: 0 -4px 20px rgba(0,0,0,0.08);
  }

  .join-btn {
    background: var(--btn);
    color: #fff;
    border: none;
    font-size: 17px;
    font-weight: 800;
    padding: 18px 0;
    width: 92%;
    max-width: 500px;
    border-radius: 14px;
    cursor: pointer;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 10px;
    -webkit-tap-highlight-color: transparent;
    box-shadow: 0 6px 24px rgba(15,76,129,0.3);
    transition: all 0.3s ease;
  }

  .join-btn:active { transform: scale(0.98); }

  .join-btn:hover {
    background: var(--btn-hover);
    box-shadow: 0 8px 30px rgba(15,76,129,0.4);
  }

  .btn-icon { font-size: 20px; }

  /* 버튼 아이콘 이미지 (BAND) */
  .btn-icon-img{
    width: 20px;
    height: 20px;
    display: inline-block;
  }

  /* 모바일에서 버튼이 너무 커 보이지 않게 */
  @media (max-width: 420px){
    .fixed-bottom{
      padding: 10px 0;
      padding-bottom: calc(10px + env(safe-area-inset-bottom));
    }
    .join-btn{
      font-size: 15px;
      padding: 14px 0;
      gap: 8px;
      border-radius: 12px;
    }
    .btn-icon-img{
      width: 18px;
      height: 18px;
    }
    .join-reminder-keyword {
      font-size: 18px;
      padding: 10px 20px;
    }
  }

  /* 푸터 */
  footer {
    background: #f9fafb;
    padding: 32px 20px 110px 20px;
    font-size: 11px;
    color: #6b7280;
    text-align: left;
    border-top: 1px solid var(--line);
    margin-top: 32px;
  }

  .footer-links { text-align: center; margin-bottom: 20px;  display: flex;  justify-content: center;}

  .footer-links a {
    color: var(--accent);
    text-decoration: none;
    font-weight: 800;
    display: inline-block;
    margin: 0 10px;
    font-size: 13px;
    transition: opacity 0.2s;
  }

  .footer-links a:hover { opacity: 0.7; }

  .disclaimer {
    background: #fff;
    border: 1px solid var(--line);
    padding: 16px;
    border-radius: 12px;
    margin-bottom: 20px;
    line-height: 1.6;
    color: var(--muted);
    word-break: keep-all;
    font-size: 12px;
  }

  .disclaimer strong { color: var(--brand); font-weight: 800; }

  .company-info { border-top: 1px solid #e5e7eb; padding-top: 20px; }

  .co-name {
    font-weight: 900;
    font-size: 13px;
    color: var(--brand);
    margin: 0 0 8px 0;
  }

  .co-details {
    line-height: 1.8;
    margin: 0 0 12px 0;
    color: #6b7280;
    font-size: 11px;
  }

  .copyright {
    color: #9ca3af;
    margin: 0;
    font-family: Tahoma, sans-serif;
    font-size: 10px;
  }

  /* 애니메이션 */
  @keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
  }

  .feature-card, .post { animation: fadeIn 0.5s ease-out; }