/* =========================================================
   TIẾNG ANH MS LAN — style.css (dùng chung mọi trang)
   ========================================================= */
:root {
  /* Bảng màu thương hiệu: Navy – Gold – Cream */
  --primary: #0B254A;        /* Primary Navy */
  --primary-dark: #001838;   /* Dark Navy */
  --primary-light: #E9EEF6;  /* Navy nhạt cho nền chip/icon */
  --accent: #D4AF37;         /* Gold */
  --accent-light: #E8C76A;   /* Light Gold */
  --accent-dark: #B08D28;    /* Gold đậm cho chữ/hover */
  --cream: #F4EFE4;          /* Cream */
  --green: #10b981;          /* chỉ dùng cho thông báo thành công */
  --pink: #B08D28;
  --purple: #0B254A;
  --ink: #1F2A3D;
  --muted: #5C6B80;
  --bg: #ffffff;
  --bg-soft: #F4EFE4;
  --radius: 16px;
  --shadow: 0 6px 24px rgba(11, 37, 74, .10);
  --shadow-lg: 0 14px 40px rgba(11, 37, 74, .16);
  --header-h: 72px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: 'Be Vietnam Pro', 'Segoe UI', system-ui, -apple-system, sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.65;
  overflow-x: hidden;
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }
.container { width: min(1180px, 92%); margin-inline: auto; }

h1, h2, h3, h4 { font-family: 'Baloo 2', 'Be Vietnam Pro', 'Segoe UI', sans-serif; line-height: 1.25; }

/* ---------- Header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 1000;
  background: rgba(255, 255, 255, .92);
  backdrop-filter: blur(10px);
  box-shadow: 0 2px 12px rgba(11, 37, 74, .08);
}
.header-inner {
  height: var(--header-h);
  display: flex; align-items: center; gap: 18px;
}
.brand { display: flex; align-items: center; gap: 10px; font-weight: 800; }
.brand img { height: 52px; width: auto; border-radius: 10px; }
.brand-name { font-family: 'Baloo 2', sans-serif; font-size: 1.15rem; color: var(--primary-dark); line-height: 1.1; }
.brand-name small { display: block; font-size: .68rem; font-weight: 600; color: var(--accent-dark); letter-spacing: .12em; text-transform: uppercase; }

.main-nav { margin-left: auto; }
.main-nav > ul { display: flex; align-items: center; gap: 4px; }
.main-nav a.nav-link {
  display: block; padding: 10px 14px; border-radius: 10px;
  font-weight: 600; font-size: .95rem; color: var(--ink);
  transition: .2s;
}
.main-nav a.nav-link:hover, .main-nav a.nav-link.active { color: var(--primary); background: var(--primary-light); }

.has-dropdown { position: relative; }
.has-dropdown > a::after { content: " ▾"; font-size: .7em; }
.dropdown {
  position: absolute; top: calc(100% + 6px); left: 0; min-width: 210px;
  background: #fff; border-radius: 12px; box-shadow: var(--shadow-lg);
  padding: 8px; opacity: 0; visibility: hidden; transform: translateY(8px);
  transition: .22s;
}
.has-dropdown:hover .dropdown, .has-dropdown:focus-within .dropdown {
  opacity: 1; visibility: visible; transform: translateY(0);
}
.dropdown a { display: block; padding: 9px 14px; border-radius: 8px; font-weight: 600; font-size: .92rem; }
.dropdown a:hover { background: var(--primary-light); color: var(--primary); }

.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 11px 22px; border-radius: 999px; font-weight: 700; font-size: .95rem;
  border: none; cursor: pointer; transition: .22s; text-align: center;
}
.btn-primary { background: linear-gradient(135deg, var(--primary), var(--primary-dark)); color: #fff; box-shadow: 0 6px 18px rgba(11, 37, 74, .35); }
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 10px 24px rgba(11, 37, 74, .45); }
.btn-accent { background: linear-gradient(135deg, var(--accent), var(--accent-dark)); color: #fff; box-shadow: 0 6px 18px rgba(176, 141, 40, .35); }
.btn-accent:hover { transform: translateY(-2px); }
.btn-outline { background: #fff; color: var(--primary); border: 2px solid var(--primary); }
.btn-outline:hover { background: var(--primary-light); }

.nav-toggle {
  display: none; margin-left: auto;
  width: 46px; height: 46px; border: none; border-radius: 12px;
  background: var(--primary-light); color: var(--primary-dark);
  font-size: 1.4rem; cursor: pointer;
}

/* ---------- Hero ---------- */
.hero {
  background:
    radial-gradient(1200px 500px at 85% -10%, rgba(212, 175, 55, .18), transparent 60%),
    radial-gradient(900px 500px at 5% 110%, rgba(232, 199, 106, .14), transparent 60%),
    linear-gradient(160deg, #F7F4EB 0%, #FDFBF5 100%);
  padding: 64px 0 72px;
}
.hero-grid { display: grid; grid-template-columns: 1.15fr .85fr; gap: 48px; align-items: center; }
.hero .eyebrow {
  display: inline-block; background: #fff; color: var(--accent-dark);
  font-weight: 700; font-size: .8rem; letter-spacing: .1em; text-transform: uppercase;
  padding: 7px 16px; border-radius: 999px; box-shadow: var(--shadow); margin-bottom: 18px;
}
.hero h1 { font-size: clamp(1.9rem, 4.2vw, 3.1rem); color: var(--primary-dark); margin-bottom: 16px; }
.hero h1 .hl { color: var(--accent-dark); }
.hero p.lead { font-size: 1.08rem; color: var(--muted); max-width: 540px; margin-bottom: 28px; }
.hero-cta { display: flex; flex-wrap: wrap; gap: 14px; }
.hero-figure { position: relative; }
.hero-figure img {
  width: 100%; border-radius: 24px; box-shadow: var(--shadow-lg);
  aspect-ratio: 4 / 4.6; object-fit: cover;
}
.hero-badge {
  position: absolute; left: -18px; bottom: 26px;
  background: #fff; border-radius: 14px; box-shadow: var(--shadow-lg);
  padding: 12px 18px; font-weight: 700; font-size: .9rem; color: var(--primary-dark);
}
.hero-badge span { display: block; color: var(--accent-dark); font-size: 1.15rem; }

.cred-list { display: grid; gap: 12px; margin: 22px 0 30px; }
.cred-list li {
  display: flex; gap: 12px; align-items: flex-start;
  background: #fff; padding: 13px 18px; border-radius: 14px; box-shadow: var(--shadow);
  font-weight: 600;
}
.cred-list .ic { font-size: 1.25rem; line-height: 1.4; }

/* ---------- Sections ---------- */
.section { padding: 76px 0; }
.section.alt { background: var(--bg-soft); }
.section-head { text-align: center; max-width: 720px; margin: 0 auto 46px; }
.section-head .kicker {
  display: inline-block; color: var(--primary); background: var(--primary-light);
  font-weight: 700; font-size: .78rem; letter-spacing: .12em; text-transform: uppercase;
  padding: 6px 15px; border-radius: 999px; margin-bottom: 14px;
}
.section-head h2 { font-size: clamp(1.6rem, 3vw, 2.3rem); color: var(--primary-dark); margin-bottom: 12px; }
.section-head p { color: var(--muted); }

/* ---------- Cards khoá học ---------- */
.course-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 22px; }
.course-card {
  background: #fff; border-radius: var(--radius); overflow: hidden;
  box-shadow: var(--shadow); transition: .25s; display: flex; flex-direction: column;
}
.course-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-lg); }
.course-card .thumb { aspect-ratio: 4 / 3; overflow: hidden; }
.course-card .thumb img { width: 100%; height: 100%; object-fit: cover; transition: .4s; }
.course-card:hover .thumb img { transform: scale(1.06); }
.course-card .body { padding: 20px 20px 24px; display: flex; flex-direction: column; gap: 8px; flex: 1; }
.course-card h3 { color: var(--primary-dark); font-size: 1.2rem; }
.course-card p { color: var(--muted); font-size: .93rem; flex: 1; }
.course-card .link { font-weight: 700; color: var(--primary); font-size: .93rem; }
.course-card .link::after { content: " →"; transition: .2s; }
.course-card:hover .link::after { padding-left: 4px; }

/* ---------- Skills 4 kỹ năng ---------- */
.skill-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 22px; }
.skill-card {
  background: #fff; border-radius: var(--radius); padding: 28px 22px;
  box-shadow: var(--shadow); text-align: center; transition: .25s;
  border-top: 5px solid var(--primary);
}
.skill-card:nth-child(2) { border-top-color: var(--accent); }
.skill-card:nth-child(3) { border-top-color: var(--accent-light); }
.skill-card:nth-child(4) { border-top-color: var(--primary-dark); }
.skill-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-lg); }
.skill-card .ic {
  width: 62px; height: 62px; margin: 0 auto 14px; border-radius: 18px;
  display: grid; place-items: center; font-size: 1.8rem; background: var(--primary-light);
}
.skill-card h3 { font-size: 1.12rem; color: var(--primary-dark); margin-bottom: 8px; }
.skill-card p { color: var(--muted); font-size: .9rem; }

/* ---------- L.A.N steps ---------- */
.lan-steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; counter-reset: step; }
.lan-step {
  position: relative; background: #fff; border-radius: var(--radius);
  padding: 34px 24px 26px; box-shadow: var(--shadow);
}
.lan-step .letter {
  position: absolute; top: -22px; left: 24px;
  width: 48px; height: 48px; border-radius: 14px; display: grid; place-items: center;
  font-family: 'Baloo 2', sans-serif; font-weight: 800; font-size: 1.4rem; color: #fff;
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  box-shadow: 0 8px 18px rgba(11, 37, 74, .4);
}
.lan-step:nth-child(2) .letter { background: linear-gradient(135deg, var(--accent), var(--accent-dark)); box-shadow: 0 8px 18px rgba(232, 199, 106, .4); }
.lan-step:nth-child(3) .letter { background: linear-gradient(135deg, var(--accent-light), var(--accent)); box-shadow: 0 8px 18px rgba(212, 175, 55, .4); }
.lan-step h3 { color: var(--primary-dark); margin-bottom: 8px; }
.lan-step p { color: var(--muted); font-size: .94rem; }

/* ---------- Dải bìa giáo trình ---------- */
.book-strip-wrap { position: relative; }
.book-strip {
  display: flex; align-items: center;
  gap: 18px; overflow-x: auto; padding: 8px 4px 18px;
  scroll-snap-type: x mandatory; scrollbar-width: thin;
}
.book-strip > * { scroll-snap-align: start; flex: 0 0 auto; }
.book-strip img {
  border-radius: 12px; box-shadow: var(--shadow); background: #fff;
  height: 235px; width: auto; max-width: 340px; object-fit: contain; transition: .25s;
}
.book-strip a img { box-shadow: var(--shadow); }
.book-strip img:hover { transform: translateY(-5px); box-shadow: var(--shadow-lg); }
.strip-btn {
  position: absolute; top: 42%; transform: translateY(-50%);
  width: 42px; height: 42px; border-radius: 50%; border: none; cursor: pointer;
  background: #fff; color: var(--primary-dark); font-size: 1.1rem; font-weight: 800;
  box-shadow: var(--shadow-lg); z-index: 5; transition: .2s;
}
.strip-btn:hover { background: var(--primary); color: #fff; }
.strip-btn.prev { left: -14px; }
.strip-btn.next { right: -14px; }

/* ---------- Feedback ---------- */
.feedback-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.feedback-grid figure {
  border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow);
  cursor: zoom-in; transition: .25s; background: #fff;
}
.feedback-grid figure:hover { transform: translateY(-5px); box-shadow: var(--shadow-lg); }
.feedback-grid img { width: 100%; aspect-ratio: 3 / 4; object-fit: cover; object-position: top; }

/* Lightbox */
.lightbox {
  position: fixed; inset: 0; z-index: 2000; display: none;
  background: rgba(15, 23, 42, .88); padding: 4vh 4vw;
  align-items: center; justify-content: center;
}
.lightbox.open { display: flex; }
.lightbox img { max-width: 92vw; max-height: 88vh; border-radius: 14px; box-shadow: 0 20px 60px rgba(0,0,0,.5); object-fit: contain; }
.lightbox-close {
  position: absolute; top: 20px; right: 26px; border: none; cursor: pointer;
  width: 46px; height: 46px; border-radius: 50%; background: rgba(255,255,255,.14);
  color: #fff; font-size: 1.3rem;
}

/* ---------- Trang khoá học ---------- */
.page-hero {
  background:
    radial-gradient(900px 400px at 90% -20%, rgba(212,175,55,.25), transparent 60%),
    linear-gradient(150deg, var(--primary-dark), var(--primary) 70%, #16407C);
  color: #fff; padding: 66px 0; text-align: center;
}
.page-hero .crumbs { font-size: .85rem; opacity: .85; margin-bottom: 12px; }
.page-hero .crumbs a:hover { text-decoration: underline; }
.page-hero h1 { font-size: clamp(1.8rem, 4vw, 2.7rem); margin-bottom: 10px; }
.page-hero p { max-width: 640px; margin: 0 auto; opacity: .92; }

.banner-pair { display: grid; grid-template-columns: 1fr 1fr; gap: 22px; }
.banner-pair img { border-radius: var(--radius); box-shadow: var(--shadow); width: 100%; object-fit: cover; }
.banner-pair.single { grid-template-columns: 1fr; max-width: 860px; margin-inline: auto; }

.split-2 { display: grid; grid-template-columns: 1.25fr .75fr; gap: 30px; align-items: center; }
.section-illus {
  border-radius: var(--radius); box-shadow: var(--shadow);
  width: 100%; max-width: 420px; margin-inline: auto; display: block;
}
.goal-list { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.split-2 .goal-list { grid-template-columns: 1fr; }
.goal-list li {
  display: flex; gap: 12px; background: #fff; border-radius: 14px;
  padding: 15px 18px; box-shadow: var(--shadow); font-weight: 600; align-items: flex-start;
}
.goal-list .ic { color: var(--accent-dark); font-size: 1.15rem; }

.book-list { display: grid; gap: 12px; max-width: 760px; margin-inline: auto; }
.book-list li {
  display: flex; gap: 12px; align-items: flex-start;
  background: #fff; border-radius: 14px; padding: 15px 20px; box-shadow: var(--shadow); font-weight: 600;
}

/* Timeline lộ trình */
.timeline { position: relative; max-width: 860px; margin-inline: auto; padding-left: 34px; }
.timeline::before {
  content: ""; position: absolute; left: 11px; top: 8px; bottom: 8px; width: 4px;
  background: linear-gradient(var(--primary), var(--accent)); border-radius: 4px;
}
.tl-item { position: relative; padding: 0 0 30px 22px; }
.tl-item:last-child { padding-bottom: 0; }
.tl-item::before {
  content: ""; position: absolute; left: -31px; top: 6px;
  width: 22px; height: 22px; border-radius: 50%;
  background: #fff; border: 6px solid var(--primary);
}
.tl-item:nth-child(even)::before { border-color: var(--accent); }
.tl-card { background: #fff; border-radius: var(--radius); box-shadow: var(--shadow); padding: 22px 26px; }
.tl-card h3 { color: var(--primary-dark); margin-bottom: 4px; }
.tl-card .dur {
  display: inline-block; background: var(--primary-light); color: var(--primary-dark);
  font-size: .78rem; font-weight: 700; border-radius: 999px; padding: 3px 12px; margin-bottom: 10px;
}
.tl-card ul { display: grid; grid-template-columns: 1fr 1fr; gap: 6px 18px; }
.tl-card ul li { position: relative; padding-left: 20px; font-size: .93rem; color: #374151; }
.tl-card ul li::before { content: "✦"; position: absolute; left: 0; color: var(--accent); }

/* CTA band */
.cta-band {
  background: linear-gradient(135deg, var(--primary-dark), var(--primary));
  border-radius: 22px; color: #fff; padding: 44px 40px;
  display: flex; flex-wrap: wrap; align-items: center; gap: 24px; justify-content: space-between;
  box-shadow: var(--shadow-lg);
}
.cta-band h2 { font-size: clamp(1.3rem, 2.6vw, 1.8rem); margin-bottom: 6px; }
.cta-band p { opacity: .9; }
.cta-band .btn-accent { flex-shrink: 0; }

/* ---------- Form ---------- */
.form-card { background: #fff; border-radius: 20px; box-shadow: var(--shadow-lg); padding: 34px; }
.form-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
.form-field { display: flex; flex-direction: column; gap: 6px; }
.form-field.full { grid-column: 1 / -1; }
.form-field label { font-weight: 700; font-size: .9rem; color: var(--primary-dark); }
.form-field input, .form-field select, .form-field textarea {
  font: inherit; padding: 12px 15px; border-radius: 12px;
  border: 2px solid #e5e7eb; background: #FBFAF6; transition: .2s; width: 100%;
}
.form-field input:focus, .form-field select:focus, .form-field textarea:focus {
  outline: none; border-color: var(--primary); background: #fff;
  box-shadow: 0 0 0 4px rgba(11, 37, 74, .12);
}
.form-field .err { color: #dc2626; font-size: .8rem; font-weight: 600; min-height: 1em; }
.form-note { font-size: .85rem; color: var(--muted); margin-top: 14px; }
.form-success {
  display: none; background: #ecfdf5; border: 2px solid var(--green);
  color: #065f46; font-weight: 600; border-radius: 14px; padding: 16px 20px; margin-bottom: 18px;
}
.form-success.show { display: block; }

/* ---------- Liên hệ ---------- */
.contact-grid { display: grid; grid-template-columns: 1fr 1.1fr; gap: 30px; align-items: start; }
.contact-info { display: grid; gap: 16px; }
.contact-item {
  display: flex; gap: 15px; background: #fff; border-radius: 16px;
  padding: 18px 20px; box-shadow: var(--shadow); align-items: flex-start;
}
.contact-item .ic {
  width: 46px; height: 46px; flex-shrink: 0; border-radius: 13px;
  display: grid; place-items: center; font-size: 1.25rem; background: var(--primary-light);
}
.contact-item h3 { font-size: 1rem; color: var(--primary-dark); }
.contact-item p, .contact-item a { color: var(--muted); font-size: .92rem; }
.contact-item a:hover { color: var(--primary); }
.map-embed { border-radius: 20px; overflow: hidden; box-shadow: var(--shadow-lg); }
.map-embed iframe { width: 100%; height: 380px; border: 0; display: block; }

/* ---------- Thư viện ---------- */
.lib-tools { display: flex; flex-wrap: wrap; gap: 12px; margin-bottom: 30px; justify-content: center; }
.lib-search {
  flex: 1 1 320px; max-width: 420px; padding: 12px 18px; font: inherit;
  border: 2px solid #e5e7eb; border-radius: 999px; background: #fff;
}
.lib-search:focus { outline: none; border-color: var(--primary); box-shadow: 0 0 0 4px rgba(29,78,216,.12); }
.chip {
  border: 2px solid #e5e7eb; background: #fff; border-radius: 999px;
  padding: 9px 18px; font-weight: 700; font-size: .88rem; cursor: pointer; transition: .2s;
}
.chip.active, .chip:hover { border-color: var(--primary); background: var(--primary-light); color: var(--primary-dark); }
.lib-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.lib-card {
  background: #fff; border-radius: var(--radius); box-shadow: var(--shadow);
  padding: 24px; display: flex; flex-direction: column; gap: 10px; transition: .25s;
}
.lib-card:hover { transform: translateY(-5px); box-shadow: var(--shadow-lg); }
.lib-card .tag {
  align-self: flex-start; font-size: .72rem; font-weight: 800; letter-spacing: .08em;
  text-transform: uppercase; padding: 4px 12px; border-radius: 999px;
  background: var(--primary-light); color: var(--primary-dark);
}
.lib-card .tag.audio { background: #F1E7CE; color: #8A6D1F; }
.lib-card .tag.video { background: #FBF3DC; color: #8A6D1F; }
.lib-card h3 { font-size: 1.05rem; color: var(--primary-dark); }
.lib-card p { color: var(--muted); font-size: .9rem; flex: 1; }
.lib-empty { text-align: center; color: var(--muted); padding: 40px 0; display: none; }

/* ---------- Trang Unit (giáo trình) ---------- */
.unit-nav {
  display: flex; flex-wrap: wrap; gap: 10px; justify-content: center; margin-bottom: 40px;
}
.lesson-block { margin-bottom: 46px; }
.lesson-block > h2 {
  font-size: 1.5rem; color: var(--primary-dark); margin-bottom: 20px;
  display: flex; align-items: center; gap: 12px;
}
.lesson-block > h2 .num {
  width: 42px; height: 42px; border-radius: 12px; display: grid; place-items: center;
  background: linear-gradient(135deg, var(--primary), var(--primary-dark)); color: #fff; font-size: 1.05rem;
}
.task-group { border-radius: var(--radius); padding: 22px 24px; margin-bottom: 18px; background: #fff; box-shadow: var(--shadow); border-left: 6px solid var(--purple); }
.task-group.vocab { border-left-color: var(--accent); }
.task-group.speak { border-left-color: var(--accent-light); }
.task-group h3 { font-size: 1.02rem; margin-bottom: 14px; }
.task-group.lecture h3 { color: var(--purple); }
.task-group.vocab h3 { color: var(--accent-dark); }
.task-group.speak h3 { color: var(--accent-dark); }
.task-table { width: 100%; border-collapse: collapse; font-size: .93rem; }
.task-table th { text-align: left; color: var(--muted); font-size: .78rem; text-transform: uppercase; letter-spacing: .06em; padding: 6px 10px; }
.task-table td { padding: 10px; border-top: 1px solid #f1f5f9; vertical-align: top; }
.task-table td:first-child { font-weight: 700; white-space: nowrap; }
.task-table .note { color: var(--muted); font-size: .85rem; }
.task-link {
  display: inline-flex; align-items: center; gap: 6px; color: var(--primary);
  font-weight: 600; word-break: break-word;
}
.task-link:hover { text-decoration: underline; }
.video-embed { border-radius: 14px; overflow: hidden; box-shadow: var(--shadow); aspect-ratio: 16/9; margin-bottom: 14px; }
.video-embed iframe { width: 100%; height: 100%; border: 0; display: block; }
.video-row { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; margin-bottom: 14px; }

/* ---------- Notice ---------- */
.notice {
  background: #FBF6E6; border: 2px dashed var(--accent);
  border-radius: 14px; padding: 16px 20px; color: #7A6014; font-size: .93rem; margin-bottom: 30px;
}

/* ---------- Footer ---------- */
.site-footer {
  background: linear-gradient(160deg, var(--primary-dark), var(--primary));
  color: #E7ECF3; margin-top: 40px;
}
.footer-grid {
  display: grid; grid-template-columns: 1.3fr 1fr 1fr 1.2fr; gap: 34px; padding: 56px 0 40px;
}
.site-footer h3 { color: #fff; font-size: 1.02rem; margin-bottom: 15px; }
.site-footer .brand-name { color: #fff; }
.site-footer .brand-name small { color: var(--accent-light); }
.footer-links li { margin-bottom: 9px; }
.footer-links a { opacity: .85; font-size: .93rem; transition: .2s; }
.footer-links a:hover { opacity: 1; color: var(--accent-light); }
.footer-contact li { display: flex; gap: 10px; margin-bottom: 11px; font-size: .93rem; opacity: .9; }
.social-row { display: flex; gap: 10px; margin-top: 16px; }
.social-row a {
  width: 42px; height: 42px; border-radius: 12px; display: grid; place-items: center;
  background: rgba(255,255,255,.1); font-size: 1.1rem; transition: .2s;
}
.social-row a:hover { background: var(--accent); transform: translateY(-3px); }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,.12);
  padding: 18px 0; text-align: center; font-size: .85rem; opacity: .75;
}

/* ---------- Floating buttons ---------- */
.float-actions { position: fixed; right: 18px; bottom: 20px; z-index: 1500; display: grid; gap: 12px; }
.float-btn {
  width: 54px; height: 54px; border-radius: 50%;
  display: grid; place-items: center; font-size: 1.35rem; color: #fff;
  box-shadow: 0 10px 26px rgba(0,0,0,.28); transition: .22s; position: relative;
}
.float-btn:hover { transform: scale(1.1); }
.float-zalo { background: #0068ff; font-weight: 800; font-size: .8rem; }
.float-phone { background: var(--accent); animation: ring 2.4s infinite; }
@keyframes ring {
  0%, 100% { box-shadow: 0 10px 26px rgba(0,0,0,.28), 0 0 0 0 rgba(212,175,55,.5); }
  50% { box-shadow: 0 10px 26px rgba(0,0,0,.28), 0 0 0 14px rgba(212,175,55,0); }
}
#backTop {
  width: 46px; height: 46px; border: none; cursor: pointer; border-radius: 50%;
  background: #fff; color: var(--primary-dark); font-size: 1.1rem;
  box-shadow: var(--shadow-lg); opacity: 0; pointer-events: none; transition: .25s;
  justify-self: center;
}
#backTop.show { opacity: 1; pointer-events: auto; }

/* ---------- Reveal animation ---------- */
.reveal { opacity: 0; transform: translateY(26px); transition: opacity .6s ease, transform .6s ease; }
.reveal.visible { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
  html { scroll-behavior: auto; }
}

/* ---------- Ảnh placeholder khi lỗi tải ---------- */
.img-ph {
  display: grid; place-items: center; text-align: center;
  background: linear-gradient(135deg, var(--primary-light), var(--cream));
  color: var(--primary-dark); font-weight: 700; font-size: .85rem;
  padding: 14px; width: 100%; height: 100%; min-height: 120px;
  border-radius: inherit;
}

/* ---------- Responsive ---------- */
@media (max-width: 1024px) {
  .course-grid, .skill-grid { grid-template-columns: repeat(2, 1fr); }
  .lib-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 860px) {
  .hero-grid { grid-template-columns: 1fr; gap: 34px; }
  .hero-figure { max-width: 420px; margin-inline: auto; }
  .split-2 { grid-template-columns: 1fr; }
  .lan-steps { grid-template-columns: 1fr; gap: 34px; }
  .contact-grid, .video-row, .banner-pair { grid-template-columns: 1fr; }
  .goal-list, .tl-card ul, .form-grid { grid-template-columns: 1fr; }
  .feedback-grid { grid-template-columns: 1fr; max-width: 440px; margin-inline: auto; }

  .nav-toggle { display: grid; place-items: center; }
  .header-cta { display: none; }
  .main-nav {
    position: fixed; inset: var(--header-h) 0 auto 0; z-index: 999;
    background: #fff; box-shadow: 0 18px 30px rgba(30,58,138,.18);
    max-height: 0; overflow: hidden; transition: max-height .3s ease;
  }
  .main-nav.open { max-height: 80vh; overflow-y: auto; }
  .main-nav > ul { flex-direction: column; align-items: stretch; gap: 0; padding: 12px 18px 20px; }
  .main-nav a.nav-link { padding: 13px 12px; border-bottom: 1px solid #f1f5f9; border-radius: 0; }
  .dropdown {
    position: static; opacity: 1; visibility: visible; transform: none;
    box-shadow: none; padding: 0 0 0 18px; min-width: 0;
  }
  .dropdown a { border-bottom: 1px solid #f8fafc; }
}
@media (max-width: 560px) {
  .course-grid, .skill-grid, .lib-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .section { padding: 56px 0; }
  .cta-band { padding: 32px 24px; }
  .book-strip img { height: 175px; max-width: 260px; }
}