:root {
  /* Official CEA Red */
  --md-primary-fg-color: #E2001A;
  --md-primary-fg-color--light: #EB3348;
  --md-primary-fg-color--dark: #C10016;

  /* Soft Light Neutrals */
  --md-primary-bg-color: #FFFFFF;
  --md-primary-bg-color--light: #F5F7F9;
}

/* --- SECTION 1: THE BRAND HEADER --- */
.md-header {
  background-color: var(--md-primary-fg-color);
  color: #FFFFFF;
  box-shadow: 0 2px 10px rgba(226, 0, 26, 0.15);
}

.md-header__topic {
  color: #FFFFFF !important;
  font-weight: 700;
}

/* --- SECTION 2: THE NAVIGATION TABS (Light Mode) --- */
.md-tabs {
  background-color: #F8F9FB;
  border-bottom: 1px solid #E0E4E8;
}

/* Trạng thái tab bình thường */
.md-tabs__link {
  color: #455A64 !important;
  opacity: 0.7;
  font-weight: 500;
  transition: all 0.2s ease;
}

/* Khi di chuột qua (Hover) */
.md-tabs__link:hover {
  opacity: 1;
  color: var(--md-primary-fg-color) !important;
}

/* TRẠNG THÁI ACTIVE: Khắc phục lỗi bị trắng khó nhìn */
.md-tabs__item--active .md-tabs__link {
  color: var(--md-primary-fg-color) !important;
  /* Chữ chuyển đỏ thay vì trắng */
  opacity: 1 !important;
  font-weight: 700;
}

/* Thanh gạch chân đỏ cho tab đang chọn */
.md-tabs__link--active {
  border-bottom: 3px solid var(--md-primary-fg-color) !important;
}

/* --- SECTION 3: LINKS IN CONTENT --- */
.md-content a {
  color: #0D47A1;
  /* Blue */
  text-decoration: none;
}

.md-content a:hover {
  color: #1565C0;
  /* Lighter blue on hover */
  text-decoration: underline;
}

.md-typeset .grid.cards>ul>li {
  border-left: 4px solid var(--md-primary-fg-color);
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.md-typeset .grid.cards>ul>li:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 18px rgba(0, 0, 0, 0.12);
}

/* --- SECTION 4: SIDEBAR & NAV (Tùy chỉnh thêm để đồng bộ) --- */
.md-nav__link--active {
  color: var(--md-primary-fg-color) !important;
  font-weight: 700;
}

.md-nav__link:hover {
  color: var(--md-primary-fg-color--light) !important;
}

/* --- SECTION 5: SDG METHOD CARDS --- */
.sdg-cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.5rem;
  margin-top: 2rem;
  margin-bottom: 2rem;
}

a.sdg-card {
  position: relative;
  background-color: var(--md-default-bg-color);
  border: 1px solid var(--md-default-fg-color--lightest, #E0E4E8);
  border-radius: 0;
  border-left: 4px solid var(--md-primary-fg-color);
  overflow: hidden;
  cursor: pointer;
  text-align: center;
  transition: transform 0.3s ease, box-shadow 0.3s ease, border-left-color 0.3s ease;
  min-height: 240px;
  display: flex;
  flex-direction: column;
  text-decoration: none !important;
  color: inherit !important;
}

a.sdg-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
  border-left-color: transparent;
}

.sdg-card-front {
  padding: 2rem 1.5rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  flex-grow: 1;
}

.sdg-logo {
  max-width: 90px;
  max-height: 90px;
  object-fit: contain;
  margin-bottom: 1.25rem;
}

.sdg-card h3 {
  margin: 0;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--md-typeset-color);
}