/* =============================================================
   Học Tiếng Anh Cùng Con — Main Stylesheet
   Font: Nunito (rounded, hỗ trợ tiếng Việt đầy đủ)
   Phong cách: Cambly Kids–inspired · Warm earth tones · Playful
   ============================================================= */

/* ── Custom Properties ─────────────────────────────────────── */
:root {
  /* Brand — warm orange palette */
  --primary: #FF8F57;
  /* Cambly orange */
  --primary-dark: #E8733A;
  --primary-light: #FFE0CC;
  --secondary: #FFB47D;
  /* Cambly tan */
  --secondary-dark: #D4874A;
  --secondary-light: #FFF0E3;

  /* Backgrounds — warm cream */
  --bg: #FAF4EB;
  --bg-card: #FFFFFF;
  --bg-alt: #F5EEE4;
  --bg-dark: #191142;
  /* Cambly navy */

  /* Text */
  --text: #262625;
  --text-secondary: #5E5952;
  --text-muted: #9E9189;
  --text-on-dark: #FFFFFF;

  /* Borders */
  --border: #E4DBD3;
  --border-strong: #BEB4AB;

  /* Accent colors */
  --accent-purple: #6840A8;
  --accent-teal: #44A6CF;
  --accent-green: #3C7F20;

  /* Shadows — subtle, warm */
  --shadow-xs: 0 1px 4px rgba(94, 89, 82, .08);
  --shadow-sm: 0 2px 10px rgba(94, 89, 82, .10);
  --shadow: 0 4px 20px rgba(94, 89, 82, .12);
  --shadow-hover: 0 8px 32px rgba(255, 143, 87, .22);
  --shadow-card: 0 2px 12px rgba(94, 89, 82, .08);

  /* Radii */
  --radius-sm: 10px;
  --radius: 16px;
  --radius-lg: 24px;
  --radius-xl: 32px;
  --radius-pill: 999px;

  /* Spacing */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 48px;
  --space-2xl: 80px;

  /* Container */
  --container-max: 1280px;
  --container-px: 24px;

  --transition: 0.2s ease;
}

/* ── Reset & Base ───────────────────────────────────────────── */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Nunito', system-ui, sans-serif;
  font-size: 16px;
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}

a {
  text-decoration: none;
  color: inherit;
}

img {
  max-width: 100%;
  display: block;
}

h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: 'Nunito', system-ui, sans-serif;
  font-weight: 800;
  line-height: 1.25;
  color: var(--text);
}

h1 {
  font-size: clamp(22px, 4vw, 32px);
  letter-spacing: -0.02em;
}

h2 {
  font-size: clamp(18px, 3vw, 24px);
  letter-spacing: -0.01em;
}

h3 {
  font-size: clamp(16px, 2.5vw, 20px);
}

h4 {
  font-size: clamp(15px, 2vw, 17px);
}

/* ── Top Stripe ─────────────────────────────────────────────── */
.top-stripe {
  height: 4px;
  background: linear-gradient(90deg,
      #FF8F57 0%, #FFB47D 35%, #6840A8 65%, #FF8F57 100%);
  background-size: 200% 100%;
  animation: stripeScroll 5s linear infinite;
}

@keyframes stripeScroll {
  0% {
    background-position: 0% 0;
  }

  100% {
    background-position: 200% 0;
  }
}

/* ── Container ──────────────────────────────────────────────── */
.container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-px);
}

/* ── Section ────────────────────────────────────────────────── */
.section {
  padding: var(--space-xl) 0;
}

.section-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 24px;
  gap: 12px;
}

.section-title {
  font-size: clamp(20px, 3.5vw, 26px);
  font-weight: 800;
  color: var(--text);
}

.see-all {
  font-size: 14px;
  font-weight: 700;
  color: var(--primary);
  white-space: nowrap;
  transition: color var(--transition);
  padding: 6px 14px;
  border-radius: var(--radius-pill);
  border: 2px solid var(--primary-light);
  background: transparent;
  transition: background var(--transition), color var(--transition);
}

.see-all:hover {
  background: var(--primary-light);
  color: var(--primary-dark);
}

/* ── Navigation ─────────────────────────────────────────────── */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  /* drawer dùng position: absolute cần neo vào đây */
  isolation: isolate;
  background: rgba(250, 244, 235, .95);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1.5px solid var(--border);
}

.nav-inner {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-px);
  height: 68px;
  display: flex;
  align-items: center;
  gap: 20px;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}

.nav-logo-dot {
  width: 40px;
  height: 40px;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  box-shadow: 0 3px 10px rgba(255, 143, 87, .35);
  flex-shrink: 0;
}

.nav-logo-name {
  font-size: 17px;
  font-weight: 900;
  color: var(--text);
  line-height: 1.2;
  letter-spacing: -.2px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 2px;
  flex: 1;
}

.nav-links a {
  font-size: 15px;
  font-weight: 700;
  color: var(--text-secondary);
  padding: 7px 14px;
  border-radius: var(--radius-sm);
  transition: color var(--transition), background var(--transition);
}

.nav-links a:hover {
  color: var(--text);
  background: var(--bg-alt);
}

.nav-cta {
  display: inline-flex;
  align-items: center;
  padding: 10px 22px;
  background: var(--primary);
  color: #fff !important;
  font-size: 15px;
  font-weight: 800;
  border-radius: var(--radius-pill);
  white-space: nowrap;
  box-shadow: 0 3px 12px rgba(255, 143, 87, .4);
  transition: background var(--transition), transform var(--transition), box-shadow var(--transition);
  flex-shrink: 0;
}

.nav-cta:hover {
  background: var(--primary-dark);
  transform: translateY(-1px);
  box-shadow: 0 5px 18px rgba(255, 143, 87, .45);
}

.nav-burger {
  display: none;
  width: 40px;
  height: 40px;
  border: none;
  background: none;
  cursor: pointer;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  flex-shrink: 0;
  padding: 0;
  border-radius: var(--radius-sm);
  transition: background var(--transition);
}

.nav-burger:hover {
  background: var(--bg-alt);
}

.nav-burger span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: transform 0.2s, opacity 0.15s;
  transform-origin: center;
}

.nav.is-open .nav-burger span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav.is-open .nav-burger span:nth-child(2) {
  opacity: 0;
}

.nav.is-open .nav-burger span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

.nav-drawer {
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  z-index: 99;
  display: flex;
  flex-direction: column;
  background: rgba(250, 244, 235, .97);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1.5px solid var(--border);
  padding: 8px 0 14px;
  /* animation */
  opacity: 0;
  transform: translateY(-8px);
  pointer-events: none;
  transition: opacity 0.22s ease, transform 0.22s ease;
}

.nav-drawer a {
  font-size: 15px;
  font-weight: 700;
  color: var(--text-secondary);
  padding: 12px var(--container-px);
  transition: color var(--transition), background var(--transition);
}

.nav-drawer a:hover {
  color: var(--text);
  background: var(--bg-alt);
}

.nav.is-open .nav-drawer {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}

/* ── Buttons ─────────────────────────────────────────────────── */
.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 30px;
  background: var(--primary);
  color: #fff;
  font-family: 'Nunito', sans-serif;
  font-size: 16px;
  font-weight: 800;
  border-radius: var(--radius-pill);
  border: none;
  cursor: pointer;
  box-shadow: 0 4px 14px rgba(255, 143, 87, .38);
  transition: background var(--transition), transform var(--transition), box-shadow var(--transition);
  letter-spacing: .1px;
}

.btn-primary:hover {
  background: var(--primary-dark);
  transform: translateY(-2px);
  box-shadow: 0 7px 22px rgba(255, 143, 87, .45);
}

.btn-outline {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 30px;
  background: transparent;
  color: var(--text);
  font-family: 'Nunito', sans-serif;
  font-size: 16px;
  font-weight: 800;
  border-radius: var(--radius-pill);
  border: 2.5px solid var(--border-strong);
  cursor: pointer;
  transition: border-color var(--transition), background var(--transition), transform var(--transition);
  letter-spacing: .1px;
}

.btn-outline:hover {
  border-color: var(--primary);
  background: var(--secondary-light);
  transform: translateY(-2px);
}

/* ── Hero Banner ─────────────────────────────────────────────── */
.hero {
  background: var(--bg);
  padding: 72px var(--container-px) 64px;
  position: relative;
  overflow: hidden;
}

/* Decorative blobs */
.hero::before {
  content: '';
  position: absolute;
  width: 500px;
  height: 500px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(255, 180, 125, .25) 0%, transparent 70%);
  top: -150px;
  right: -100px;
  pointer-events: none;
}

.hero::after {
  content: '';
  position: absolute;
  width: 300px;
  height: 300px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(104, 64, 168, .12) 0%, transparent 70%);
  bottom: -60px;
  left: 5%;
  pointer-events: none;
}

.hero-inner {
  max-width: var(--container-max);
  margin: 0 auto;
  display: flex;
  align-items: center;
  position: relative;
  z-index: 1;
}

.hero-text {
  max-width: 620px;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--secondary-light);
  color: var(--secondary-dark);
  font-size: 13px;
  font-weight: 800;
  padding: 6px 16px;
  border-radius: var(--radius-pill);
  margin-bottom: 22px;
  border: 1.5px solid #F5CEAD;
  letter-spacing: .2px;
}

.hero-text h1 {
  font-size: clamp(30px, 5vw, 48px);
  font-weight: 900;
  margin-bottom: 18px;
  color: var(--text);
  line-height: 1.15;
  letter-spacing: -.5px;
}

.hero-text h1 em {
  font-style: normal;
  color: var(--primary);
}

.hero-text p {
  font-size: clamp(15px, 2.2vw, 18px);
  color: var(--text-secondary);
  margin-bottom: 32px;
  max-width: 500px;
  font-weight: 500;
  line-height: 1.7;
}

.hero-btns {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
}

/* Hero with background image */
.hero-bg-img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center center;
  z-index: 0;
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(to right, rgb(255 255 255 / 59%) 40%, rgb(255 255 255 / 0%) 70%, rgb(255 255 255 / 59%) 100%);
  z-index: 0;
}

/* ── Stat Bar ────────────────────────────────────────────────── */
.stat-bar {
  background: var(--bg-dark);
  padding: 24px var(--container-px);
  display: flex;
  justify-content: center;
  gap: clamp(28px, 8vw, 96px);
  flex-wrap: wrap;
}

.stat-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  color: #fff;
  min-width: 70px;
}

.stat-num {
  font-size: clamp(26px, 4vw, 36px);
  font-weight: 900;
  line-height: 1;
  color: var(--secondary);
  letter-spacing: -.5px;
}

.stat-label {
  font-size: 13px;
  font-weight: 600;
  color: rgba(255, 255, 255, .65);
  margin-top: 4px;
}

/* ── Card base ───────────────────────────────────────────────── */
.card {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  border: 1.5px solid var(--border);
  box-shadow: var(--shadow-card);
  transition: transform var(--transition), box-shadow var(--transition);
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

.card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-hover);
}

/* ── Category Grid ───────────────────────────────────────────── */
.cat-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 14px;
}

.cat-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 24px 14px 20px;
  border-radius: var(--radius-lg);
  border: 2px solid transparent;
  text-align: center;
  cursor: pointer;
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
}

.cat-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow);
}

.cat-icon {
  width: 56px;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 32px;
  margin-bottom: 12px;
  flex-shrink: 0;
  line-height: 1;
}

.cat-name {
  font-size: 18px;
  font-weight: 800;
  line-height: 1.3;
  color: var(--text);
}

.cat-count {
  font-size: 13px;
  font-weight: 600;
  margin-top: 4px;
  color: var(--text-muted);
  min-height: 2.2em;
  line-height: 1.4;
  text-align: center;
}

/* Category color variants */
.cat-blue {
  background: #E8F4FD;
  border-color: #C5E3F7;
}

.cat-blue .cat-name {
  color: #0A6FA8;
}

.cat-blue:hover {
  border-color: #44A6CF;
  box-shadow: 0 6px 20px rgba(68, 166, 207, .2);
}

.cat-green {
  background: #EAF7EC;
  border-color: #C3E9C8;
}

.cat-green .cat-name {
  color: #2D7A37;
}

.cat-green:hover {
  border-color: #3C7F20;
  box-shadow: 0 6px 20px rgba(60, 127, 32, .18);
}

.cat-orange {
  background: var(--secondary-light);
  border-color: #F5CEAD;
}

.cat-orange .cat-name {
  color: var(--primary-dark);
}

.cat-orange:hover {
  border-color: var(--primary);
  box-shadow: 0 6px 20px rgba(255, 143, 87, .22);
}

.cat-pink {
  background: #FDF0F5;
  border-color: #F5C8DA;
}

.cat-pink .cat-name {
  color: #B5295A;
}

.cat-pink:hover {
  border-color: #E06090;
  box-shadow: 0 6px 20px rgba(224, 96, 144, .2);
}

.cat-purple {
  background: #F3EEF9;
  border-color: #D8C9EF;
}

.cat-purple .cat-name {
  color: var(--accent-purple);
}

.cat-purple:hover {
  border-color: var(--accent-purple);
  box-shadow: 0 6px 20px rgba(104, 64, 168, .18);
}

.cat-yellow {
  background: #FFFAED;
  border-color: #FAE89A;
}

.cat-yellow .cat-name {
  color: #9A6E00;
}

.cat-yellow:hover {
  border-color: #F5CE40;
  box-shadow: 0 6px 20px rgba(245, 206, 64, .25);
}

/* ── Post Grid & Card ────────────────────────────────────────── */
.post-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(290px, 1fr));
  gap: 20px;
}

.post-card {
  display: flex;
  flex-direction: column;
}

.post-card-thumb {
  width: 100%;
  aspect-ratio: 16/9;
  background: linear-gradient(135deg, var(--secondary-light), var(--primary-light));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 44px;
  overflow: hidden;
  flex-shrink: 0;
  border-radius: var(--radius-lg) var(--radius-lg) 0 0;
}

.post-card-body {
  padding: 18px 20px 20px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  flex: 1;
}

.post-card-tag {
  display: inline-flex;
  align-self: flex-start;
  font-size: 13px;
  font-weight: 800;
  padding: 4px 12px;
  background: var(--secondary-light);
  color: var(--secondary-dark);
  border-radius: var(--radius-pill);
  letter-spacing: .3px;
  border: 1.5px solid #F5CEAD;
  text-transform: uppercase;
}

.post-card-title {
  font-size: 18px;
  font-weight: 800;
  color: var(--text);
  line-height: 1.35;
  transition: color var(--transition);
}

.post-card:hover .post-card-title {
  color: var(--primary-dark);
}

.post-card-meta {
  font-size: 14px;
  font-weight: 600;
  color: var(--text-muted);
  margin-top: auto;
  padding-top: 8px;
  border-top: 1px solid var(--border);
}

/* ── Resource Grid & Card ────────────────────────────────────── */
.res-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 16px;
}

.res-card {
  display: flex;
  flex-direction: column;
}

.res-card-body {
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  flex: 1;
}

.res-card-name {
  font-size: 15px;
  font-weight: 800;
  color: var(--text);
  line-height: 1.35;
  transition: color var(--transition);
}

.res-card:hover .res-card-name {
  color: var(--primary-dark);
}

.res-card-desc {
  font-size: 13px;
  font-weight: 500;
  color: var(--text-muted);
  line-height: 1.55;
  flex: 1;
}

.res-card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  margin-top: 10px;
  flex-wrap: wrap;
}

/* ── Exercise Card ───────────────────────────────────────────── */
.ex-card {
  display: flex;
  flex-direction: column;
}

.ex-card-body {
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  flex: 1;
}

.ex-card-title {
  font-size: 15px;
  font-weight: 800;
  color: var(--text);
  line-height: 1.35;
  transition: color var(--transition);
}

.ex-card:hover .ex-card-title {
  color: var(--primary-dark);
}

.ex-card-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 6px;
}

/* ── Badges ─────────────────────────────────────────────────── */
.badge {
  display: inline-flex;
  align-items: center;
  font-size: 11px;
  font-weight: 800;
  padding: 4px 11px;
  border-radius: var(--radius-pill);
  white-space: nowrap;
  letter-spacing: .2px;
}

.badge-free {
  background: #EAF7EC;
  color: #2D7A37;
  border: 1.5px solid #C3E9C8;
}

.badge-pro {
  background: #FFFAED;
  color: #9A6E00;
  border: 1.5px solid #FAE89A;
}

.badge-level {
  background: var(--secondary-light);
  color: var(--primary-dark);
  border: 1.5px solid #F5CEAD;
}

.badge-skill {
  background: #E8F4FD;
  color: #0A6FA8;
  border: 1.5px solid #C5E3F7;
}

.badge-age {
  margin-left: 10px;
  background: #F3EEF9;
  color: var(--accent-purple);
  border: 1.5px solid #D8C9EF;
}

/* ── Newsletter ──────────────────────────────────────────────── */
.newsletter {
  background: var(--bg-dark);
  padding: 64px var(--container-px);
  position: relative;
  overflow: hidden;
}

.newsletter::before {
  content: '';
  position: absolute;
  width: 400px;
  height: 400px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(255, 143, 87, .15) 0%, transparent 70%);
  top: -100px;
  right: 0;
  pointer-events: none;
}

.newsletter::after {
  content: '';
  position: absolute;
  width: 300px;
  height: 300px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(104, 64, 168, .2) 0%, transparent 70%);
  bottom: -80px;
  left: 5%;
  pointer-events: none;
}

.newsletter-inner {
  max-width: 520px;
  margin: 0 auto;
  text-align: center;
  position: relative;
  z-index: 1;
}

.newsletter-inner h3 {
  font-size: clamp(22px, 4vw, 30px);
  font-weight: 900;
  color: #fff;
  margin-bottom: 12px;
  letter-spacing: -.3px;
}

.newsletter-inner p {
  font-size: 15px;
  font-weight: 500;
  color: rgba(255, 255, 255, .72);
  margin-bottom: 28px;
  line-height: 1.65;
}

.newsletter-form {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.newsletter-row {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  justify-content: center;
}

.newsletter-input {
  flex: 1;
  min-width: 220px;
  padding: 13px 20px;
  border-radius: var(--radius-pill);
  border: 2px solid rgba(255, 255, 255, .2);
  background: rgba(255, 255, 255, .1);
  font-family: 'Nunito', sans-serif;
  font-size: 15px;
  font-weight: 600;
  color: #fff;
  outline: none;
  transition: border-color var(--transition), background var(--transition);
}

.newsletter-input:focus {
  border-color: var(--primary);
  background: rgba(255, 255, 255, .15);
}

.newsletter-input::placeholder {
  color: rgba(255, 255, 255, .45);
}

/* ── Filter Bar ──────────────────────────────────────────────── */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 14px;
}

.filter-pill {
  display: inline-flex;
  align-items: center;
  font-size: 13px;
  font-weight: 700;
  padding: 7px 16px;
  border-radius: var(--radius-pill);
  background: var(--bg-card);
  color: var(--text-secondary);
  border: 1.5px solid var(--border);
  cursor: pointer;
  transition: background var(--transition), color var(--transition), border-color var(--transition), transform var(--transition);
}

.filter-pill:hover {
  border-color: var(--primary);
  color: var(--primary-dark);
  background: var(--secondary-light);
  transform: translateY(-1px);
}

.filter-pill.active {
  background: var(--bg-dark);
  color: #fff;
  border-color: var(--bg-dark);
}

/* ── Breadcrumb ──────────────────────────────────────────────── */
.breadcrumb {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 4px;
  padding: 14px 0;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-muted);
}

.breadcrumb a {
  color: var(--primary-dark);
  font-weight: 700;
  transition: color var(--transition);
}

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

.breadcrumb-sep {
  color: var(--border-strong);
  font-size: 14px;
}

/* ── Pagination ──────────────────────────────────────────────── */
.pagination {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 6px;
  padding: 32px 0 8px;
  flex-wrap: wrap;
}

.page-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 40px;
  height: 40px;
  padding: 0 10px;
  border-radius: var(--radius-sm);
  font-size: 14px;
  font-weight: 800;
  border: 2px solid var(--border);
  background: var(--bg-card);
  color: var(--text-secondary);
  transition: background var(--transition), color var(--transition), border-color var(--transition), transform var(--transition);
}

.page-btn:hover {
  border-color: var(--primary);
  color: var(--primary-dark);
  transform: translateY(-1px);
}

.page-btn.active {
  background: var(--bg-dark);
  color: #fff;
  border-color: var(--bg-dark);
  box-shadow: 0 3px 12px rgba(25, 17, 66, .3);
}

/* ── Empty State ─────────────────────────────────────────────── */
.empty-state {
  text-align: center;
  padding: 64px 20px;
}

.empty-state-icon {
  font-size: 60px;
  margin-bottom: 18px;
}

.empty-state h3 {
  font-size: 22px;
  margin-bottom: 8px;
  color: var(--text);
}

.empty-state p {
  color: var(--text-muted);
  font-size: 15px;
  font-weight: 500;
}

/* ── Footer Wave Divider ─────────────────────────────────────── */
.footer-wave {
  position: relative;
  background: var(--bg);
  line-height: 0;
  margin-top: var(--space-2xl);
}

.footer-wave svg {
  width: 100%;
  height: 64px;
  display: block;
}

.footer-wave-icons {
  position: absolute;
  bottom: 6px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  align-items: center;
  gap: 18px;
  white-space: nowrap;
}

.footer-wave-icons span {
  font-size: 20px;
  opacity: .5;
  animation: waveIconBob 3s ease-in-out infinite;
  display: inline-block;
}

.footer-wave-icons span:nth-child(2) {
  animation-delay: .3s;
}

.footer-wave-icons span:nth-child(3) {
  animation-delay: .6s;
}

.footer-wave-icons span:nth-child(4) {
  animation-delay: .9s;
}

.footer-wave-icons span:nth-child(5) {
  animation-delay: 1.2s;
}

.footer-wave-icons span:nth-child(6) {
  animation-delay: 1.5s;
}

.footer-wave-icons span:nth-child(7) {
  animation-delay: 1.8s;
}

.footer-wave-icons span:nth-child(8) {
  animation-delay: 2.1s;
}

@keyframes waveIconBob {

  0%,
  100% {
    transform: translateY(0);
  }

  50% {
    transform: translateY(-5px);
  }
}

/* ── Footer ──────────────────────────────────────────────────── */
.footer {
  background: var(--bg-dark);
}

.footer-inner {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-px);
}

/* Brand + Links row */
.footer-top {
  padding: 48px 0 36px;
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 56px;
  align-items: start;
}

/* Brand column */
.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.footer-logo-name {
  font-size: 19px;
  font-weight: 900;
  color: #fff;
  letter-spacing: -.2px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.footer-tagline {
  font-size: 14px;
  font-weight: 500;
  color: rgba(255, 255, 255, .5);
  line-height: 1.65;
  margin: 0;
}

/* Social buttons */
.footer-social {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 4px;
}

.footer-social-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  font-weight: 700;
  color: rgba(255, 255, 255, .7);
  padding: 6px 14px;
  border-radius: var(--radius-pill);
  border: 1.5px solid rgba(255, 255, 255, .15);
  background: rgba(255, 255, 255, .06);
  transition: background var(--transition), color var(--transition), border-color var(--transition);
}

.footer-social-btn:hover {
  background: rgba(255, 143, 87, .18);
  color: var(--secondary);
  border-color: rgba(255, 143, 87, .4);
}

/* Link columns */
.footer-links {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 32px;
}

.footer-col {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-col h4 {
  font-size: 12px;
  font-weight: 800;
  color: rgba(255, 255, 255, .4);
  letter-spacing: 1px;
  text-transform: uppercase;
  margin-bottom: 4px;
}

.footer-col a {
  font-size: 14px;
  font-weight: 600;
  color: rgba(255, 255, 255, .6);
  transition: color var(--transition);
}

.footer-col a:hover {
  color: #fff;
}

/* Bottom bar */
.footer-bottom {
  padding: 18px 0;
  border-top: 1px solid rgba(255, 255, 255, .08);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

.footer-copy {
  font-size: 13px;
  font-weight: 500;
  color: rgba(255, 255, 255, .28);
}

.footer-bottom-links {
  display: flex;
  gap: 20px;
}

.footer-bottom-links a {
  font-size: 13px;
  font-weight: 600;
  color: rgba(255, 255, 255, .35);
  transition: color var(--transition);
}

.footer-bottom-links a:hover {
  color: rgba(255, 255, 255, .7);
}

/* ── AdSense / Ad units ──────────────────────────────────────── */
.ad-unit {
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-alt);
  border: 1.5px dashed var(--border-strong);
  border-radius: var(--radius);
  min-height: 90px;
  overflow: hidden;
  margin: var(--space-lg) 0;
}

.ad-unit-wide {
  width: 100%;
  min-height: 90px;
}

.ad-unit-rect {
  width: 100%;
  min-height: 280px;
}

/* ── Rich-text / Article content ────────────────────────────── */
.prose {
  font-size: 16px;
  font-weight: 500;
  line-height: 1.78;
  color: var(--text);
  max-width: 720px;
}

.prose h2 {
  font-size: clamp(18px, 3vw, 22px);
  font-weight: 800;
  color: var(--text);
  margin: 36px 0 14px;
}

.prose h3 {
  font-size: clamp(16px, 2.5vw, 19px);
  font-weight: 800;
  color: var(--text-secondary);
  margin: 26px 0 10px;
}

.prose p {
  margin-bottom: 16px;
}

.prose ul,
.prose ol {
  margin: 0 0 16px 24px;
}

.prose li {
  margin-bottom: 6px;
}

.prose strong {
  font-weight: 800;
  color: var(--text);
}

.prose blockquote {
  border-left: 4px solid var(--primary);
  background: var(--secondary-light);
  padding: 16px 20px;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 22px 0;
  color: var(--text-secondary);
  font-style: italic;
  font-weight: 600;
}

.prose img {
  border-radius: var(--radius-lg);
  margin: 24px 0;
  box-shadow: var(--shadow);
}

.prose code {
  background: var(--bg-alt);
  padding: 2px 8px;
  border-radius: 6px;
  font-size: .88em;
  font-family: 'Courier New', monospace;
  color: var(--primary-dark);
  font-weight: 700;
}

.prose pre {
  background: var(--bg-dark);
  color: var(--secondary-light);
  padding: 20px;
  border-radius: var(--radius-lg);
  overflow-x: auto;
  margin: 22px 0;
}

.prose a {
  color: var(--primary-dark);
  font-weight: 700;
}

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

/* ── Page layout (detail pages) ─────────────────────────────── */
.page-body {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: var(--space-xl) var(--container-px);
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: 40px;
  align-items: start;
}

.page-main {
  min-width: 0;
}

.page-sidebar {
  display: flex;
  flex-direction: column;
  gap: 24px;
  position: sticky;
  top: 88px;
}

.sidebar-card {
  background: var(--bg-card);
  border: 1.5px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 22px;
  box-shadow: var(--shadow-card);
}

.sidebar-card h4 {
  font-size: 14px;
  font-weight: 800;
  color: var(--text);
  margin-bottom: 14px;
  padding-bottom: 12px;
  border-bottom: 1.5px solid var(--border);
  letter-spacing: .3px;
  text-transform: uppercase;
}

/* ── Responsive ──────────────────────────────────────────────── */
@media (max-width: 768px) {
  .nav-links {
    display: none;
  }

  .nav-inner {
    justify-content: space-between;
  }

  .nav-burger {
    display: flex;
  }

  .hero-bg-img {
    object-position: center right;
  }

  .hero {
    padding: 48px var(--container-px) 40px;
  }

  .hero-btns {
    flex-direction: column;
    align-items: flex-start;
  }

  .btn-primary,
  .btn-outline {
    width: 100%;
    max-width: 300px;
  }

  .cat-grid {
    grid-template-columns: repeat(3, 1fr);
  }

  .nav-logo-name {
    display: none;
  }

  .post-grid {
    grid-template-columns: 1fr;
  }

  .res-grid {
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  }

  .footer-wave {
    margin-top: var(--space-xl);
  }

  .footer-top {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .footer-links {
    grid-template-columns: repeat(2, 1fr);
    gap: 24px;
  }

  .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
  }

  .page-body {
    grid-template-columns: 1fr;
  }

  .page-sidebar {
    position: static;
  }

  .section {
    padding: 32px 0;
  }

  .newsletter {
    padding: 48px var(--container-px);
  }

  .newsletter-row {
    flex-direction: column;
    align-items: stretch;
  }

  .newsletter-input {
    min-width: unset;
  }

  .newsletter-row .btn-primary {
    width: 100%;
  }

  .stat-bar {
    gap: 24px;
  }
}

@media (max-width: 480px) {
  body {
    font-size: 15px;
  }

  .cat-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  /* Item lẻ cuối hàng → canh giữa */
  .cat-card:last-child:nth-child(odd) {
    grid-column: 1 / -1;
    justify-self: center;
    width: calc(50% - 7px);
  }

  .filter-bar {
    gap: 6px;
  }

  .filter-pill {
    font-size: 12px;
    padding: 5px 12px;
  }
}

@media (min-width: 1100px) {
  .post-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* =============================================================
   Course Player — Tabs + Sidebar + Content
   ============================================================= */

/* ── Tab Bar ────────────────────────────────────────────────── */
.course-tabs-bar {
  background: var(--bg-card);
  border-bottom: 2px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 80;
}

.course-tabs-inner {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-px);
  display: flex;
  gap: 0;
  overflow-x: auto;
  scrollbar-width: none;
}

.course-tabs-inner::-webkit-scrollbar {
  display: none;
}

.course-tab {
  flex-shrink: 0;
  display: inline-block;
  padding: 14px 20px;
  font-size: 14px;
  font-weight: 700;
  color: var(--text-muted);
  border-bottom: 3px solid transparent;
  margin-bottom: -2px;
  transition: color var(--transition), border-color var(--transition);
  white-space: nowrap;
}

.course-tab:hover {
  color: var(--text);
}

.course-tab.is-active {
  color: var(--primary-dark);
  border-bottom-color: var(--primary);
}

/* ── Player Grid ────────────────────────────────────────────── */
.course-player {
  display: grid;
  grid-template-columns: 360px 1fr;
  min-height: calc(100vh - 120px);
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-px);
}

/* ── Sidebar ────────────────────────────────────────────────── */
.course-sidebar {
  border-right: 1px solid var(--border);
  background: var(--bg-card);
  position: sticky;
  top: 53px;
  /* height of tab bar */
  height: calc(100vh - 53px);
  overflow-y: auto;
  scrollbar-width: thin;
  scrollbar-color: var(--border) transparent;
}

.course-sidebar-inner {
  padding: 12px 0;
}

.course-lesson-link {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 10px 16px;
  font-size: 13.5px;
  color: var(--text-secondary);
  border-left: 3px solid transparent;
  transition: background var(--transition), color var(--transition), border-color var(--transition);
  line-height: 1.4;
}

.course-lesson-link:hover {
  background: var(--bg-alt);
  color: var(--text);
}

.course-lesson-link.is-active {
  background: var(--primary-light);
  color: var(--primary-dark);
  border-left-color: var(--primary);
  font-weight: 800;
}

.course-lesson-num {
  flex-shrink: 0;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 11px;
  font-weight: 800;
  color: var(--text-muted);
  margin-top: 1px;
}

.course-lesson-link.is-active .course-lesson-num {
  background: var(--primary);
  color: #fff;
}

.course-lesson-name {
  flex: 1;
}

/* ── Content Area ───────────────────────────────────────────── */
.course-content {
  background: var(--bg);
  overflow-y: auto;
}

.course-content-inner {
  max-width: 760px;
  margin: 0 auto;
  padding: 40px var(--container-px) 80px;
}

.course-lesson-heading {
  font-size: 28px;
  font-weight: 900;
  color: var(--text);
  margin-bottom: 12px;
  line-height: 1.25;
}

.course-lesson-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 24px;
}

/* ── Audio ──────────────────────────────────────────────────── */
.course-audios {
  margin: 24px 0;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

/* Custom audio player card */
.caudio {
  display: flex;
  align-items: center;
  gap: 14px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-left: 3px solid var(--primary);
  border-radius: var(--radius);
  padding: 14px 18px;
  transition: box-shadow 0.18s;
}

.caudio:hover {
  box-shadow: 0 4px 16px rgba(255, 143, 87, .12);
}

.caudio.is-playing {
  border-left-color: var(--primary-dark);
  box-shadow: 0 4px 20px rgba(255, 143, 87, .18);
}

.caudio-btn {
  flex-shrink: 0;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--primary);
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  transition: background 0.15s, transform 0.12s;
}

.caudio-btn:hover {
  background: var(--primary-dark);
  transform: scale(1.07);
}

.caudio-btn:active {
  transform: scale(0.95);
}

.caudio-body {
  flex: 1;
  min-width: 0;
}

.caudio-label {
  font-size: 13px;
  font-weight: 700;
  color: var(--text-secondary);
  margin-bottom: 8px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.caudio-track {
  display: flex;
  align-items: center;
  gap: 10px;
}

.caudio-bar {
  flex: 1;
  height: 5px;
  background: var(--border);
  border-radius: 3px;
  cursor: pointer;
  position: relative;
}

.caudio-bar:hover {
  height: 7px;
}

.caudio-bar:hover .caudio-thumb {
  opacity: 1;
}

.caudio-fill {
  height: 100%;
  background: var(--primary);
  border-radius: 3px;
  width: 0%;
  pointer-events: none;
  position: relative;
}

.caudio-thumb {
  position: absolute;
  right: -6px;
  top: 50%;
  transform: translateY(-50%);
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--primary-dark);
  opacity: 0;
  transition: opacity 0.15s;
}

.caudio-times {
  font-size: 12px;
  color: var(--text-muted);
  white-space: nowrap;
  font-variant-numeric: tabular-nums;
  display: flex;
  gap: 2px;
}

.caudio-speeds {
  display: flex;
  gap: 4px;
  margin-top: 8px;
  flex-wrap: wrap;
}

.caudio-speed {
  padding: 2px 7px;
  font-size: 11px;
  font-weight: 600;
  border-radius: 20px;
  border: 1px solid var(--border);
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  transition: background 0.13s, color 0.13s, border-color 0.13s;
  line-height: 1.6;
}

.caudio-speed:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.caudio-speed.is-active {
  background: var(--primary);
  border-color: var(--primary);
  color: #fff;
}

/* ── Images ─────────────────────────────────────────────────── */
.course-images {
  margin: 24px 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 16px;
}

.course-image-figure {
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--bg-card);
  border: 1px solid var(--border);
}

.course-image {
  width: 100%;
  height: auto;
  display: block;
}

.course-image-caption {
  padding: 8px 12px;
  font-size: 13px;
  color: var(--text-muted);
  text-align: center;
}

/* ── Prev/Next nav ──────────────────────────────────────────── */
.course-lesson-nav {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  margin-top: 48px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
}

.course-nav-btn {
  display: inline-flex;
  align-items: flex-start;
  gap: 6px;
  padding: 10px 18px;
  border-radius: var(--radius);
  background: var(--bg-card);
  border: 1.5px solid var(--border);
  font-size: 13px;
  font-weight: 700;
  color: var(--text);
  transition: background var(--transition), border-color var(--transition), color var(--transition);
  max-width: 48%;
  line-height: 1.4;
}

.course-nav-btn:hover {
  background: var(--primary-light);
  border-color: var(--primary);
  color: var(--primary-dark);
}

/* ── Responsive ─────────────────────────────────────────────── */
@media (max-width: 768px) {
  .course-player {
    grid-template-columns: 1fr;
    min-height: unset;
  }

  .course-sidebar {
    position: static;
    height: auto;
    max-height: 220px;
    border-right: none;
    border-bottom: 1px solid var(--border);
  }

  .course-content-inner {
    padding: 24px 0 48px;
  }

  .course-lesson-heading {
    font-size: 22px;
  }

  .course-tab {
    padding: 12px 14px;
    font-size: 13px;
  }

  .course-images {
    grid-template-columns: 1fr;
  }
}

/* ── Post content typography ─────────────────────────────────── */
.post-content {
  font-size: 17px;
  line-height: 1.85;
  color: var(--text);
  word-break: break-word;
  overflow-wrap: break-word;
}

.post-content>*+* {
  margin-top: 1.2em;
}

/* Headings */
.post-content h2 {
  font-size: clamp(20px, 3vw, 26px);
  font-weight: 800;
  line-height: 1.3;
  color: var(--text);
  margin: 2.2em 0 0.6em;
  padding-bottom: 0.35em;
  border-bottom: 2px solid var(--primary-light);
  letter-spacing: -0.01em;
}

.post-content h3 {
  font-size: clamp(17px, 2.5vw, 21px);
  font-weight: 800;
  line-height: 1.35;
  color: var(--text);
  margin: 1.8em 0 0.5em;
}

.post-content h4 {
  font-size: clamp(15px, 2vw, 18px);
  font-weight: 700;
  line-height: 1.4;
  color: var(--text-secondary);
  margin: 1.5em 0 0.4em;
}

/* Paragraphs */
.post-content p {
  margin-bottom: 1.15em;
}

.post-content p:last-child {
  margin-bottom: 0;
}

/* Links */
.post-content a {
  color: var(--primary-dark);
  font-weight: 700;
  text-decoration: underline;
  text-decoration-thickness: 2px;
  text-underline-offset: 3px;
  transition: color var(--transition);
}

.post-content a:hover {
  color: var(--primary);
}

/* Lists */
.post-content ul,
.post-content ol {
  padding-left: 1.5em;
  margin: 0.8em 0 1.2em;
}

.post-content li {
  margin-bottom: 0.45em;
  line-height: 1.7;
}

.post-content li::marker {
  color: var(--primary);
}

.post-content ol li::marker {
  font-weight: 700;
}

/* Blockquote */
.post-content blockquote {
  border-left: 4px solid var(--primary);
  background: var(--secondary-light);
  padding: 16px 20px 16px 24px;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 1.6em 0;
  color: var(--text-secondary);
  font-style: italic;
  font-weight: 600;
  font-size: 1.02em;
}

/* Bold / em */
.post-content strong {
  font-weight: 800;
  color: var(--text);
}

.post-content em {
  font-style: italic;
}

/* Code */
.post-content code {
  background: var(--bg-alt);
  padding: 2px 8px;
  border-radius: 6px;
  font-size: 0.87em;
  font-family: 'Courier New', monospace;
  color: var(--primary-dark);
  font-weight: 700;
}

.post-content pre {
  background: var(--bg-dark);
  color: var(--secondary-light);
  padding: 20px 24px;
  border-radius: var(--radius);
  overflow-x: auto;
  margin: 1.6em 0;
  font-size: 0.88em;
  line-height: 1.65;
}

.post-content pre code {
  background: none;
  padding: 0;
  color: inherit;
  font-size: inherit;
}

/* Figure / Image */
.post-content figure {
  margin: 2em 0;
}

.post-content figure img {
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  width: 100%;
  height: auto;
  display: block;
}

.post-content figcaption {
  font-size: 0.82em;
  color: var(--text-muted);
  text-align: center;
  margin-top: 0.5em;
  line-height: 1.5;
  font-style: italic;
}

/* Inline img (not in figure) */
.post-content img {
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  margin: 1.6em auto;
  max-width: 100%;
  height: auto;
  display: block;
}

/* Horizontal rule */
.post-content hr {
  border: none;
  border-top: 2px solid var(--border);
  margin: 2.5em 0;
}

/* First paragraph lead-in */
.post-content>p:first-of-type {
  font-size: 1.06em;
  color: var(--text-secondary);
  line-height: 1.8;
}

/* Responsive */
@media (max-width: 640px) {
  .post-content {
    font-size: 16px;
  }

  .post-content h2 {
    font-size: 20px;
  }

  .post-content h3 {
    font-size: 17px;
  }

  .post-content h4 {
    font-size: 15px;
  }
}