/* Anh ngữ Bút Đỏ (trung-tam-tieng-anh 4.3): a tidy course catalogue. White and cool grey, ink-blue text, red as the
   teacher's correction pen (a red underline under the brand, red marks, red buttons), level badges, a search bar with
   sort and fee range, tabs by age group. Font: Montserrat only. */
:root {
  --red: #d7263d;
  --red-2: #b51d31;
  --red-soft: #fde8eb;
  --ink: #1b2a41;
  --grey: #f4f5f7;
  --muted: #5f6b7d;
  --line: #e1e4ea;
  --k-font: 'Montserrat', system-ui, sans-serif;
  --k-font-display: 'Montserrat', system-ui, sans-serif;
  --k-accent: #d7263d;
  --k-accent-ink: #ffffff;
  --k-ink: #1b2a41;
  --k-paper: #ffffff;
  --k-muted: #5f6b7d;
  --k-line: #e1e4ea;
  --k-radius: 8px;
}

body {
  background: #fff;
  color: var(--ink);
  font:
    400 16px/1.6 'Montserrat',
    system-ui,
    sans-serif;
}
a {
  color: inherit;
}
h1,
h2,
h3 {
  margin: 0;
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.02em;
  text-wrap: balance;
}
.plain {
  margin: 0;
  padding: 0;
  list-style: none;
}
.eyebrow {
  margin: 0 0 10px;
  color: var(--red);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}
.badge {
  display: inline-block;
  margin: 0 0 8px;
  padding: 3px 10px;
  border-radius: 4px;
  background: var(--red-soft);
  color: var(--red-2);
  font-size: 12px;
  font-weight: 700;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 48px;
  padding: 0 22px;
  border: 2px solid var(--red);
  border-radius: 8px;
  background: var(--red);
  color: #fff;
  font:
    700 15px/1.2 'Montserrat',
    sans-serif;
  text-decoration: none;
  cursor: pointer;
}
.btn:hover {
  background: var(--red-2);
  border-color: var(--red-2);
}
.btn-ghost {
  border-color: var(--ink);
  background: #fff;
  color: var(--ink);
}
.btn-ghost:hover {
  background: var(--grey);
  border-color: var(--ink);
}
.btn-sm {
  min-height: 44px;
  padding: 0 16px;
  font-size: 14px;
}
.btn-block {
  width: 100%;
}
.link {
  padding: 0;
  border: 0;
  background: none;
  color: inherit;
  font: inherit;
  text-decoration: underline;
  cursor: pointer;
}
.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 24px;
}
.more {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--red);
  font-weight: 700;
  text-decoration: none;
}
.back {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-bottom: 16px;
  font-weight: 700;
  text-decoration: none;
}

/* Header */
.hdr {
  position: sticky;
  top: 0;
  z-index: 30;
  background: #fff;
  border-bottom: 1px solid var(--line);
}
.hdr-in {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  max-width: 1160px;
  margin: 0 auto;
  padding: 12px 16px;
}
.brand {
  position: relative;
  margin: 0 auto 0 0;
  font-size: 20px;
  font-weight: 800;
  letter-spacing: -0.02em;
  text-decoration: none;
}
.brand::after {
  content: '';
  position: absolute;
  left: 0;
  right: 0;
  bottom: -4px;
  height: 4px;
  border-radius: 4px;
  background: var(--red);
  transform: rotate(-1.2deg);
}
.hdr-menu {
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  color: var(--ink);
  cursor: pointer;
}
.menu {
  display: none;
  flex-basis: 100%;
  flex-direction: column;
  padding: 8px 0 0;
}
.menu[data-open] {
  display: flex;
}
.menu a {
  padding: 12px 2px;
  border-top: 1px solid var(--line);
  font-weight: 600;
  text-decoration: none;
}
.menu .menu-cta {
  color: var(--red);
  font-weight: 800;
}

/* Sections */
.sec {
  padding: 44px 16px;
}
.sec > * {
  max-width: 1128px;
  margin-left: auto;
  margin-right: auto;
}
.page {
  max-width: 1160px;
  margin: 0 auto;
}
.sec-grey {
  background: var(--grey);
}
.h1 {
  font-size: 30px;
}
.h2 {
  margin-bottom: 20px;
  font-size: 25px;
}
.h3 {
  margin: 26px 0 10px;
  font-size: 19px;
}
.sec-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 4px 16px;
}

/* Hero */
.hero {
  display: grid;
  gap: 28px;
  max-width: 1160px;
  margin: 0 auto;
  padding: 32px 16px 44px;
}
.hero-title {
  font-size: 36px;
}
.mark {
  background: linear-gradient(transparent 70%, rgba(215, 38, 61, 0.28) 70%);
}
.hero-lead {
  margin: 14px 0 0;
  color: var(--muted);
  font-size: 17px;
}
.who {
  padding: 18px;
  border-radius: 12px;
  background: var(--ink);
  color: #fff;
}
.who-h {
  margin: 0 0 12px;
  font-weight: 700;
}
.who-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
}
.who-card {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 6px;
  min-height: 84px;
  padding: 12px;
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.08);
  text-decoration: none;
}
.who-card:hover {
  background: var(--red);
}
.who-name {
  font-weight: 700;
  line-height: 1.3;
}
.who-count {
  display: inline-flex;
  align-items: center;
  gap: 2px;
  color: rgba(255, 255, 255, 0.7);
  font-size: 13px;
}

/* Courses */
.courses {
  display: grid;
  gap: 14px;
}
.course {
  display: grid;
  grid-template-columns: 92px 1fr;
  gap: 4px 14px;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: #fff;
}
.course-img img {
  display: block;
  width: 92px;
  height: 92px;
  object-fit: cover;
  border-radius: 8px;
}
.course-body {
  min-width: 0;
}
.course-name {
  font-size: 17px;
  line-height: 1.3;
}
.course-name a {
  text-decoration: none;
}
.course-name a:hover {
  color: var(--red);
}
.course-line {
  display: flex;
  gap: 6px;
  margin: 6px 0 0;
  color: var(--muted);
  font-size: 14px;
}
.course-line .k-icon {
  margin-top: 2px;
}
.course-fee {
  margin: 6px 0 0;
}
.course-fee b {
  color: var(--red-2);
}
.course-fee small {
  color: var(--muted);
}
.course-act {
  grid-column: 1 / -1;
  display: flex;
  gap: 8px;
  margin-top: 10px;
}
.course-act .btn {
  flex: 1;
}

/* Stats band */
.band {
  padding: 28px 16px;
  background: var(--ink);
  color: #fff;
}
.band-in {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 18px;
  max-width: 1128px;
  margin: 0 auto;
}
.band dd {
  margin: 0;
  font-size: 30px;
  font-weight: 800;
}
.band dd::after {
  content: '';
  display: block;
  width: 28px;
  height: 3px;
  margin-top: 4px;
  background: var(--red);
}
.band dt {
  margin-top: 6px;
  color: rgba(255, 255, 255, 0.75);
  font-size: 14px;
}

/* Teachers */
.teachers {
  display: grid;
  gap: 18px;
}
.teacher {
  display: grid;
  grid-template-columns: 96px 1fr;
  gap: 14px;
  margin: 0;
}
.teacher img {
  width: 96px;
  height: 96px;
  object-fit: cover;
  border-radius: 12px;
}
.teacher figcaption {
  display: flex;
  flex-direction: column;
  line-height: 1.45;
}
.teacher b {
  font-size: 17px;
}
.teacher span {
  color: var(--red);
  font-size: 14px;
  font-weight: 600;
}
.teacher small {
  margin-top: 4px;
  color: var(--muted);
  font-size: 14px;
}

/* Flow */
.flow {
  display: grid;
  gap: 12px;
}
.flow li {
  display: grid;
  grid-template-columns: 40px 1fr;
  gap: 0 12px;
  padding: 16px;
  border-radius: 12px;
  background: #fff;
}
.flow-n {
  grid-row: span 2;
  display: grid;
  place-items: center;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  border: 2px solid var(--red);
  color: var(--red);
  font-weight: 800;
}
.flow b {
  font-size: 16px;
}
.flow li > span:last-child {
  color: var(--muted);
  font-size: 14px;
}

/* Quotes */
.quotes {
  display: grid;
  gap: 12px;
}
.quote {
  position: relative;
  margin: 0;
  padding: 18px 18px 16px 44px;
  border-left: 3px solid var(--red);
  background: var(--grey);
}
.quote::before {
  content: '“';
  position: absolute;
  top: 6px;
  left: 12px;
  color: var(--red);
  font-size: 44px;
  font-weight: 800;
  line-height: 1;
}
.quote blockquote {
  margin: 0 0 10px;
  font-size: 15px;
}
.quote figcaption {
  display: flex;
  flex-wrap: wrap;
  gap: 2px 10px;
  font-size: 13px;
}
.quote figcaption span {
  color: var(--muted);
}
.stars {
  color: #e3a008 !important;
  letter-spacing: 1px;
}

/* FAQ */
.faqs {
  display: grid;
  gap: 8px;
}
.faq {
  border-radius: 8px;
  background: #fff;
}
.faq summary {
  position: relative;
  padding: 14px 44px 14px 16px;
  font-weight: 700;
  cursor: pointer;
  list-style: none;
}
.faq summary::-webkit-details-marker {
  display: none;
}
.faq summary::after {
  content: '+';
  position: absolute;
  top: 10px;
  right: 16px;
  color: var(--red);
  font-size: 22px;
  font-weight: 800;
}
.faq[open] summary::after {
  content: '−';
}
.faq p {
  margin: 0;
  padding: 0 16px 16px;
  color: var(--muted);
  font-size: 15px;
}

/* Contact */
.contact {
  display: grid;
  gap: 18px;
  max-width: 1160px;
  margin: 0 auto;
}
.contact > * {
  max-width: none;
  margin: 0;
}
.contact-row {
  display: flex;
  gap: 8px;
  margin: 0 0 10px;
}
.contact-row .k-icon {
  margin-top: 4px;
  color: var(--red);
}
.hours li {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  max-width: 380px;
  padding: 8px 0;
  border-bottom: 1px solid var(--line);
  font-size: 15px;
}
.map {
  min-height: 280px;
  overflow: hidden;
  border-radius: 12px;
  background: var(--grey);
}

/* List */
.toolbar {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  margin: 16px 0 14px;
}
.search {
  grid-column: 1 / -1;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 0 14px;
  border: 2px solid var(--ink);
  border-radius: 8px;
}
.search input {
  flex: 1;
  min-width: 0;
  min-height: 48px;
  border: 0;
  background: none;
  color: var(--ink);
  font: inherit;
  outline: none;
}
.select {
  min-width: 0;
  min-height: 46px;
  padding: 0 10px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  color: var(--ink);
  font:
    500 14px/1 'Montserrat',
    sans-serif;
}
.tabs,
.tabs-list {
  display: flex;
  gap: 6px;
}
.tabs {
  overflow-x: auto;
  margin: 0 -16px 20px;
  padding: 0 16px 6px;
  border-bottom: 1px solid var(--line);
  scrollbar-width: none;
}
.tab {
  flex: none;
  min-height: 44px;
  padding: 0 12px;
  border: 0;
  border-bottom: 3px solid transparent;
  background: none;
  color: var(--muted);
  font:
    700 14px/1 'Montserrat',
    sans-serif;
  white-space: nowrap;
  cursor: pointer;
}
.tab[aria-pressed='true'] {
  border-bottom-color: var(--red);
  color: var(--ink);
}
.empty {
  padding: 22px;
  border-radius: 12px;
  background: var(--grey);
  text-align: center;
}

/* Detail */
.dtop {
  padding: 26px 16px 30px;
  background: var(--grey);
}
.dtop-in {
  max-width: 1128px;
  margin: 0 auto;
}
.dshort {
  max-width: 64ch;
  margin: 10px 0 0;
  color: var(--muted);
  font-size: 17px;
}
.dgrid {
  display: grid;
  gap: 24px;
  max-width: 1160px;
  margin: 0 auto;
}
.dgrid > * {
  max-width: none;
  margin: 0;
}
.dimg {
  width: 100%;
  height: 220px;
  object-fit: cover;
  border-radius: 12px;
}
.spec {
  margin: 0;
  border-top: 2px solid var(--ink);
}
.spec div {
  display: grid;
  grid-template-columns: 120px 1fr;
  gap: 12px;
  padding: 10px 0;
  border-bottom: 1px solid var(--line);
  font-size: 15px;
}
.spec dt {
  color: var(--muted);
}
.spec dd {
  margin: 0;
  font-weight: 600;
}
.box {
  display: flex;
  flex-direction: column;
  gap: 10px;
  align-self: start;
  padding: 20px;
  border: 2px solid var(--ink);
  border-radius: 12px;
  background: #fff;
}
.box-label {
  margin: 0;
  color: var(--muted);
  font-size: 13px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}
.box-fee {
  margin: -6px 0 4px;
}
.box-fee b {
  color: var(--red-2);
  font-size: 24px;
}
.box-fee small {
  color: var(--muted);
}
.box-note {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
}
.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}
.tags li {
  padding: 3px 10px;
  border-radius: 4px;
  background: var(--grey);
  font-size: 13px;
  font-weight: 600;
}

/* Order */
.order {
  display: grid;
  gap: 18px;
  margin-top: 20px;
}
.order .box {
  order: -1;
}
.form {
  padding: 20px;
  border: 1px solid var(--line);
  border-radius: 12px;
}
.order-item {
  margin: -4px 0 0;
  font-size: 18px;
  font-weight: 800;
}
.order-item:empty::before {
  content: 'Chọn khoá ở ô “Khoá học”.';
  font-size: 15px;
  font-weight: 500;
  color: var(--muted);
}
.checks {
  display: grid;
  gap: 8px;
  font-size: 14px;
}
.checks li {
  display: flex;
  gap: 8px;
}
.checks .k-icon {
  margin-top: 2px;
  color: var(--red);
}

/* Footer */
.ftr {
  background: var(--ink);
  color: rgba(255, 255, 255, 0.82);
  font-size: 15px;
}
.ftr-in {
  display: grid;
  gap: 22px;
  max-width: 1160px;
  margin: 0 auto;
  padding: 36px 16px;
}
.ftr p {
  margin: 0 0 6px;
}
.brand-ftr {
  display: inline-block;
  margin-bottom: 14px !important;
  color: #fff;
}
.ftr-h {
  color: #fff;
  font-weight: 700;
}

@media (min-width: 720px) {
  .who-grid {
    grid-template-columns: repeat(3, 1fr);
  }
  .courses {
    grid-template-columns: 1fr 1fr;
  }
  .band-in {
    grid-template-columns: repeat(4, 1fr);
  }
  .teachers,
  .quotes {
    grid-template-columns: repeat(3, 1fr);
  }
  .teacher {
    grid-template-columns: 1fr;
  }
  .teacher img {
    width: 100%;
    height: 240px;
  }
  .flow {
    grid-template-columns: repeat(4, 1fr);
  }
  .flow li {
    grid-template-columns: 1fr;
    gap: 8px;
  }
  .flow-n {
    grid-row: auto;
  }
  .ftr-in {
    grid-template-columns: 1.4fr 1fr 1fr;
  }
}

@media (min-width: 960px) {
  .hdr-in {
    flex-wrap: nowrap;
  }
  .hdr-menu {
    display: none;
  }
  .menu {
    display: flex;
    flex-basis: auto;
    flex-direction: row;
    align-items: center;
    gap: 26px;
    padding: 0;
  }
  .menu a {
    padding: 0;
    border: 0;
    font-size: 15px;
  }
  .menu .menu-cta {
    padding: 11px 18px;
    border-radius: 8px;
    background: var(--red);
    color: #fff;
  }
  .hero {
    grid-template-columns: 1.1fr 0.9fr;
    align-items: center;
    gap: 56px;
    padding: 64px 16px 72px;
  }
  .hero-title {
    font-size: 52px;
  }
  .sec {
    padding: 72px 16px;
  }
  .h1 {
    font-size: 40px;
  }
  .h2 {
    font-size: 32px;
  }
  .courses {
    grid-template-columns: repeat(3, 1fr);
  }
  .course {
    grid-template-columns: 1fr;
  }
  .course-img img {
    width: 100%;
    height: 180px;
  }
  .courses-rows {
    grid-template-columns: 1fr;
  }
  .courses-rows .course {
    grid-template-columns: 150px 1fr 200px;
    align-items: center;
  }
  .courses-rows .course-img img {
    width: 150px;
    height: 110px;
  }
  .courses-rows .course-act {
    grid-column: auto;
    flex-direction: column;
    margin: 0;
  }
  .toolbar {
    grid-template-columns: 1fr 230px 230px;
  }
  .search {
    grid-column: auto;
  }
  .tabs {
    margin: 0 0 22px;
    padding: 0;
  }
  .faqs {
    grid-template-columns: 1fr 1fr;
    align-items: start;
  }
  .contact {
    grid-template-columns: 1fr 1.3fr;
    align-items: center;
  }
  .dtop {
    padding: 40px 16px;
  }
  .dgrid {
    grid-template-columns: 1fr 340px;
    gap: 48px;
  }
  .dimg {
    height: 400px;
  }
  .box {
    position: sticky;
    top: 90px;
  }
  .order {
    grid-template-columns: 1fr 340px;
    align-items: start;
  }
  .order .box {
    order: 0;
  }
}