/* ==========================================================================
   F2F v2 · Base — reset, typography primitives, layout, buttons, links, motion
   ========================================================================== */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-padding-top: var(--header-h); }
@media (prefers-reduced-motion: no-preference) { html { scroll-behavior: smooth; } }
body {
  margin: 0; background: var(--c-bg); color: var(--c-ink);
  font-family: var(--f-sans); font-size: var(--t-body); font-weight: 400; line-height: var(--lh-body);
  -webkit-font-smoothing: antialiased; -moz-osx-font-smoothing: grayscale; overflow-x: clip;
  text-rendering: optimizeLegibility;
}
img, picture, svg { display: block; max-width: 100%; }
img { height: auto; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; background: none; border: 0; padding: 0; cursor: pointer; }
h1, h2, h3, h4, p, figure, ul, ol, dl, dd { margin: 0; }
ul[role=list], ol[role=list] { list-style: none; padding: 0; }
::selection { background: var(--c-ink); color: var(--c-bg); }
:focus-visible { outline: 1px solid currentColor; outline-offset: 4px; }

.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0; }
.skip { position: fixed; left: var(--s-4); top: var(--s-4); z-index: 100; background: var(--c-ink); color: var(--c-bg); padding: var(--s-3) var(--s-4); transform: translateY(-200%); transition: transform var(--d-fast); }
.skip:focus { transform: none; }

/* ── Layout ── */
.wrap { width: 100%; max-width: var(--max); margin: 0 auto; padding-inline: var(--gutter); }
.section { padding-block: var(--section-y); }
.section--alt { background: var(--c-bg-alt); }
.section--dark { background: var(--c-dark); color: var(--c-on-dark); }

/* ── Type primitives ── */
.eyebrow {
  display: inline-flex; align-items: center; gap: var(--s-3);
  font-size: var(--t-eyebrow); font-weight: 500; letter-spacing: var(--tr-eyebrow); text-transform: uppercase; line-height: 1.4;
}
.eyebrow--rule::before { content: ""; width: 28px; height: 1px; background: currentColor; }
.eyebrow .dot { width: 5px; height: 5px; border-radius: 50%; background: var(--c-accent); }
.display, .h1, .h2, .h3 { font-family: var(--f-serif); font-weight: 300; letter-spacing: var(--tr-head); }
.display { font-size: var(--t-display); line-height: var(--lh-tight); letter-spacing: var(--tr-display); }
.h1 { font-size: var(--t-h1); line-height: 1; letter-spacing: var(--tr-display); }
.h2 { font-size: var(--t-h2); line-height: var(--lh-head); }
.h3 { font-size: var(--t-h3); font-weight: 400; line-height: 1.15; }
.it { font-family: var(--f-serif); font-style: italic; font-weight: 300; text-transform: none; letter-spacing: -.01em; }
.lead { font-size: var(--t-lead); line-height: 1.55; color: var(--c-ink-soft); max-width: 36ch; }
.section--dark .lead { color: var(--c-on-dark-mute); }
.mute { color: var(--c-mute); }
.num { font-variant-numeric: tabular-nums; }

/* ── Buttons ──
   Chữ nhật, viền mảnh, không bo, không bóng. 1 nút chính / khu vực. */
.btn {
  --btn-bg: var(--c-ink); --btn-fg: var(--c-bg); --btn-bd: var(--c-ink);
  position: relative; display: inline-flex; align-items: center; justify-content: center; gap: var(--s-3);
  min-height: 52px; padding: 0 var(--s-6);
  background: var(--btn-bg); color: var(--btn-fg); border: 1px solid var(--btn-bd);
  font-size: 12px; font-weight: 500; letter-spacing: .16em; text-transform: uppercase; white-space: nowrap;
  overflow: hidden; isolation: isolate;
  transition: color var(--d-base) var(--ease), border-color var(--d-base) var(--ease);
}
.btn::before {
  content: ""; position: absolute; inset: 0; z-index: -1; background: var(--c-accent);
  transform: scaleY(0); transform-origin: bottom; transition: transform var(--d-base) var(--ease-out);
}
.btn:hover::before { transform: scaleY(1); }
.btn:hover { --btn-bd: var(--c-accent); color: #fff; }
.btn .arr { transition: transform var(--d-base) var(--ease-out); }
.btn:hover .arr { transform: translateX(4px); }
.btn--ghost { --btn-bg: transparent; --btn-fg: var(--c-ink); --btn-bd: var(--c-line-strong); }
.btn--ghost::before { background: var(--c-ink); }
.btn--ghost:hover { --btn-bd: var(--c-ink); color: var(--c-bg); }
.btn--light { --btn-bg: var(--c-bg); --btn-fg: var(--c-ink); --btn-bd: var(--c-bg); }
.btn--ghost-light { --btn-bg: transparent; --btn-fg: var(--c-on-dark); --btn-bd: rgba(244,241,236,.45); }
.btn--ghost-light::before { background: var(--c-bg); }
.btn--ghost-light:hover { --btn-bd: var(--c-bg); color: var(--c-ink); }
.btn--sm { min-height: 40px; padding: 0 var(--s-5); font-size: 11px; }
.btn--block { width: 100%; }
.btn[disabled] { opacity: .5; cursor: wait; }

/* ── Text link with drawn underline ── */
.tlink {
  display: inline-flex; align-items: center; gap: var(--s-2); padding-bottom: 6px;
  font-size: 12px; font-weight: 500; letter-spacing: .16em; text-transform: uppercase;
  background: linear-gradient(currentColor, currentColor) left bottom / 100% 1px no-repeat;
  transition: background-size var(--d-base) var(--ease-out);
}
.tlink:hover { background-size: 30% 1px; }

/* ── Media ── */
.media { position: relative; overflow: hidden; background: var(--c-bg-alt); }
.media img { width: 100%; height: 100%; object-fit: cover; }
.media--portrait { aspect-ratio: var(--r-portrait); }
.media--tall { aspect-ratio: var(--r-tall); }
.media--land { aspect-ratio: var(--r-land); }
.media--wide { aspect-ratio: var(--r-wide); }
.media--zoom img { transition: transform var(--d-img) var(--ease-out); }
a:hover .media--zoom img, .media--zoom:hover img { transform: scale(1.045); }

/* ── Motion: reveal ──
   Chỉ bật khi JS chạy (html.js) để không giấu nội dung khi JS lỗi. */
.js .rv { opacity: 0; transform: translateY(32px); transition: opacity var(--d-slow) var(--ease-out), transform var(--d-slow) var(--ease-out); }
.js .rv.is-in { opacity: 1; transform: none; }
/* Ảnh "mở màn" bằng LỚP PHỦ (không clip-path lên ảnh): ảnh loading="lazy" bị clip kín
   sẽ không bao giờ được trình duyệt tải → khung trắng vĩnh viễn. */
.js .rv-img::after { content: ""; position: absolute; inset: 0; z-index: 1; background: var(--c-bg-alt); transform-origin: top; transition: transform 1.3s var(--ease-out); pointer-events: none; }
.js .rv-img.is-in::after { transform: scaleY(0); }
.js .rv-img img { transform: scale(1.1); transition: transform 2s var(--ease-out); }
.js .rv-img.is-in img { transform: none; }
.js a:hover .media--zoom.rv-img.is-in img, .js .media--zoom.rv-img.is-in:hover img { transform: scale(1.045); transition-duration: var(--d-img); }
.rv[data-d="1"], .rv-img[data-d="1"]::after { transition-delay: .1s; }
.rv[data-d="2"], .rv-img[data-d="2"]::after { transition-delay: .2s; }
.rv[data-d="3"], .rv-img[data-d="3"]::after { transition-delay: .3s; }
.rv[data-d="4"], .rv-img[data-d="4"]::after { transition-delay: .4s; }
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: .01ms !important; animation-iteration-count: 1 !important; transition-duration: .01ms !important; }
  .js .rv, .js .rv-img img { opacity: 1; transform: none; }
  .js .rv-img::after { display: none; }
}