/* Nhận diện thương hiệu Bài 3 — Slow Cross Border */
:root {
  --primary: #0D9488;
  --primary-dark: #082D2A;
  --navy: #0B1A2B;
  --accent: #00B4D8;
  --orange: #FF6A1A;
  --card: #0F2338;
  --border: #1E3A5F;
  --text: #FFFFFF;
  --text-sub: #94A3B8;
  --text-soft: #E2E8F0;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: 'Montserrat', 'Plus Jakarta Sans', 'Segoe UI', system-ui, sans-serif;
  background: var(--navy);
  color: var(--text);
  line-height: 1.6;
  -webkit-text-size-adjust: 100%;
}
a { color: inherit; }
.wrap { max-width: 1040px; margin: 0 auto; padding: 0 16px; }

/* Thanh trên cùng */
header.top {
  position: sticky; top: 0; z-index: 10;
  background: rgba(11, 26, 43, 0.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}
.top .wrap { display: flex; align-items: center; justify-content: space-between; gap: 12px; height: 64px; }
.logo { background: #fff; border-radius: 10px; padding: 6px 12px; display: flex; align-items: center; }
.logo img { height: 22px; width: auto; display: block; }
nav { display: flex; gap: 20px; font-size: 14px; font-weight: 600; }
nav a { text-decoration: none; color: var(--text-sub); }
nav a:hover { color: var(--accent); }
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  background: var(--orange); color: #fff; text-decoration: none;
  font-weight: 700; font-size: 15px; padding: 12px 22px; border-radius: 10px;
  min-height: 44px;
}
.btn:hover { filter: brightness(1.08); }
.btn.ghost { background: transparent; border: 1px solid var(--accent); color: var(--accent); }
.top .btn { padding: 8px 14px; font-size: 13px; min-height: 40px; }

/* Phần mở đầu */
.hero {
  background: radial-gradient(ellipse at 85% 0%, rgba(13, 148, 136, 0.28), transparent 60%), linear-gradient(135deg, var(--primary-dark) 0%, var(--navy) 70%);
  border-bottom: 1px solid var(--border);
  padding: 64px 0 56px;
}
.eyebrow { color: var(--orange); font-weight: 700; font-size: 13px; letter-spacing: 1.5px; text-transform: uppercase; }
.hero h1 { font-size: clamp(32px, 6vw, 52px); font-weight: 800; line-height: 1.15; margin: 10px 0 6px; }
.hero .role { font-size: clamp(18px, 3vw, 24px); font-weight: 700; color: var(--accent); }
.hero p.lead { color: var(--text-soft); font-size: 17px; max-width: 640px; margin: 18px 0 26px; }
.chips { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 28px; }
.chip { border: 1px solid var(--border); background: var(--card); border-radius: 8px; padding: 6px 12px; font-size: 13px; font-weight: 700; }
.cta { display: flex; flex-wrap: wrap; gap: 12px; }

/* Các mục */
section.block { padding: 56px 0; border-bottom: 1px solid var(--border); }
.block h2 { font-size: clamp(22px, 4vw, 30px); font-weight: 800; text-transform: uppercase; margin-bottom: 8px; }
.block h2 span { color: var(--accent); }
.block .sub { color: var(--text-sub); margin-bottom: 28px; max-width: 640px; }
.grid { display: grid; gap: 16px; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); }
.card { background: var(--card); border: 1px solid var(--border); border-radius: 14px; padding: 22px; }
.card h3 { font-size: 17px; font-weight: 700; margin-bottom: 6px; }
.card p { color: var(--text-sub); font-size: 14.5px; }
.icon { width: 42px; height: 42px; border-radius: 10px; display: grid; place-items: center; background: rgba(13, 148, 136, 0.15); border: 1px solid var(--primary); margin-bottom: 14px; font-size: 20px; }

ul.check { list-style: none; display: grid; gap: 12px; }
ul.check li { display: flex; gap: 12px; align-items: flex-start; color: var(--text-soft); }
ul.check li::before { content: "✓"; flex: none; width: 24px; height: 24px; border-radius: 50%; background: var(--primary); color: #fff; font-weight: 800; font-size: 13px; display: grid; place-items: center; margin-top: 1px; }

/* Bảng giá */
.price { position: relative; }
.price .tag { display: inline-block; font-size: 12px; font-weight: 700; padding: 4px 10px; border-radius: 6px; background: var(--primary); margin-bottom: 12px; }
.price .amount { font-size: 40px; font-weight: 800; line-height: 1.1; margin: 4px 0 2px; }
.price .amount small { font-size: 15px; font-weight: 600; color: var(--text-sub); }
.price.free .amount { color: var(--accent); }
.price.free .tag { background: var(--orange); }
.price ul.check { margin-top: 16px; font-size: 14.5px; }

/* Dự án */
.project { display: grid; gap: 20px; grid-template-columns: 1fr; align-items: center; }
.project + .project { margin-top: 20px; }
.project img { width: 100%; height: auto; border-radius: 12px; border: 1px solid var(--border); display: block; }
.project .label { color: var(--orange); font-size: 12px; font-weight: 700; letter-spacing: 1px; text-transform: uppercase; }
.project h3 { font-size: 20px; margin: 4px 0 8px; }
.project ul.check { font-size: 14.5px; margin-top: 12px; }
.bot-visual { background: linear-gradient(160deg, #102c3f, var(--card)); border: 1px solid var(--border); border-radius: 12px; padding: 18px; display: grid; gap: 10px; font-size: 13.5px; }
.bubble { background: #17324d; border-radius: 12px 12px 12px 4px; padding: 10px 12px; max-width: 92%; color: var(--text-soft); }
.bubble.me { background: var(--primary); color: #fff; justify-self: end; border-radius: 12px 12px 4px 12px; }
.bubble b { color: var(--accent); }
.bubble.me b { color: #fff; }
.project-icon { aspect-ratio: 1200 / 630; display: grid; place-items: center; font-size: 72px; border-radius: 12px; border: 1px solid var(--border); background: linear-gradient(160deg, #102c3f, var(--card)); }
.muted { color: var(--text-sub); }
.sub-title { margin: 36px 0 16px; font-size: 18px; text-transform: uppercase; }
.preview-bar { background: var(--orange); color: #fff; text-align: center; font-weight: 700; font-size: 14px; padding: 10px 16px; }

/* Liên hệ */
.contact { text-align: center; }
.contact .sub { margin: 0 auto 24px; }
footer { padding: 28px 0 40px; color: var(--text-sub); font-size: 13px; text-align: center; }

@media (min-width: 820px) {
  .project { grid-template-columns: 1.1fr 1fr; gap: 32px; }
  .project.reverse > :first-child { order: 2; }
}
@media (max-width: 640px) {
  nav { display: none; }
  .hero { padding: 44px 0 40px; }
  section.block { padding: 44px 0; }
  .cta .btn { flex: 1 1 100%; }
}

/* Ô chat hỏi trợ lý AI */
.chat-fab { position: fixed; right: 16px; bottom: 16px; z-index: 30; display: inline-flex; align-items: center; gap: 8px; min-height: 48px; padding: 12px 18px; border: 0; border-radius: 999px; background: var(--primary); color: #fff; font: 700 15px 'Montserrat', system-ui, sans-serif; box-shadow: 0 8px 24px rgba(0,0,0,.35); cursor: pointer; }
.chat-fab:hover { filter: brightness(1.08); }
.chat-fab[hidden], .chat-box[hidden] { display: none; }
.chat-box { position: fixed; right: 16px; bottom: 16px; z-index: 40; width: 370px; max-width: calc(100vw - 32px); height: min(560px, calc(100dvh - 32px)); display: flex; flex-direction: column; background: var(--card); border: 1px solid var(--border); border-radius: 16px; box-shadow: 0 16px 48px rgba(0,0,0,.5); overflow: hidden; }
.chat-head { display: flex; align-items: center; justify-content: space-between; gap: 8px; padding: 12px 14px; background: linear-gradient(135deg, var(--primary-dark), var(--navy)); border-bottom: 1px solid var(--border); }
.chat-head b { display: block; font-size: 15px; }
.chat-head small { display: block; color: var(--text-sub); font-size: 12px; }
.chat-x { width: 40px; height: 40px; border: 0; border-radius: 10px; background: transparent; color: var(--text-sub); font-size: 18px; cursor: pointer; }
.chat-x:hover { background: var(--border); color: #fff; }
.chat-log { flex: 1; overflow-y: auto; padding: 14px; display: flex; flex-direction: column; gap: 10px; font-size: 14.5px; }
.msg { max-width: 88%; padding: 10px 12px; border-radius: 12px 12px 12px 4px; background: #17324d; color: var(--text-soft); white-space: pre-wrap; overflow-wrap: anywhere; }
.msg.me { align-self: flex-end; background: var(--primary); color: #fff; border-radius: 12px 12px 4px 12px; }
.msg.wait { color: var(--text-sub); font-style: italic; }
.msg-book { display: block; margin-top: 8px; color: var(--accent); font-weight: 700; text-decoration: none; }
.chat-tips { display: flex; flex-wrap: wrap; gap: 6px; }
.chat-tips button { border: 1px solid var(--accent); background: transparent; color: var(--accent); border-radius: 999px; padding: 8px 12px; min-height: 36px; font: 600 13px 'Montserrat', system-ui, sans-serif; cursor: pointer; }
.chat-form { display: flex; gap: 8px; padding: 10px; border-top: 1px solid var(--border); }
.chat-form input { flex: 1; min-width: 0; min-height: 44px; padding: 0 12px; border-radius: 10px; border: 1px solid var(--border); background: var(--navy); color: #fff; font: 16px 'Montserrat', system-ui, sans-serif; }
.chat-form input:focus { outline: 2px solid var(--accent); outline-offset: 0; }
.chat-form .btn { padding: 0 16px; }
.chat-foot { padding: 0 12px 10px; color: var(--text-sub); font-size: 11.5px; }
.chat-foot a { color: var(--accent); font-weight: 700; text-decoration: none; white-space: nowrap; }
@media (max-width: 640px) {
  .chat-box { right: 0; bottom: 0; width: 100%; max-width: 100%; height: 85dvh; border-radius: 16px 16px 0 0; }
  .chat-fab span { display: inline; }
  footer { padding-bottom: 88px; }
}