/* =====================================================================
   KYYEU — Bộ chương nâng cấp cho 45 theme kỷ yếu.
   Màu/font lấy từ biến của từng theme (đặt trong style="" của .kyu):
   --kyu-bg --kyu-surface --kyu-ink --kyu-muted --kyu-accent --kyu-display --kyu-body
   Phong cách khối: .kyu-s-paper | dark | glass | frame | pastel | ink
   ===================================================================== */
.kyu {
  position: relative; z-index: 4; isolation: isolate;
  color: var(--kyu-ink); font-family: var(--kyu-body); font-size: 16.5px; line-height: 1.75;
  -webkit-font-smoothing: antialiased; text-rendering: optimizeLegibility; font-synthesis: none;
  padding: clamp(24px, 5vw, 64px) 0;
  background: var(--kyu-bg);
}
.kyu *, .kyu *::before, .kyu *::after { box-sizing: border-box; }
/* Chặn CSS của theme gốc tràn vào các chương (thẻ trung tính + đặt lại thuộc tính hay bị đè) */
.kyu.kyu div, .kyu.kyu p, .kyu.kyu a { float: none; text-transform: none; }
.kyu.kyu .kyu-kicker, .kyu.kyu .kyu-stat span { text-transform: uppercase; }
.kyu.kyu .kyu-ch, .kyu.kyu .kyu-wrap { border: 0; box-shadow: none; }
.kyu.kyu .kyu-ch::before, .kyu.kyu .kyu-ch::after, .kyu.kyu .kyu-h2::before, .kyu.kyu .kyu-h2::after { content: none; }
.kyu.kyu .kyu-ph img { width: 100% !important; height: 100% !important; max-width: none !important; max-height: none !important; margin: 0 !important; object-fit: cover !important; border: 0 !important; border-radius: 0 !important; box-shadow: none !important; filter: none; transform: none; opacity: 1 !important; }
.kyu.kyu.kyu-g-masonry .kyu-ph img, .kyu.kyu .kyu-g-masonry .kyu-ph img, .kyu.kyu .kyu-g-polaroid .kyu-ph img { height: auto !important; }
.kyu.kyu .kyu-ph:hover img { transform: scale(1.05); }
.kyu-ch { padding: clamp(36px, 6vw, 84px) 18px; }
.kyu-wrap { max-width: 760px; margin: 0 auto; text-align: center; }
.kyu-wrap.kyu-wide { max-width: 1080px; }

.kyu-kicker {
  display: inline-flex; align-items: center; gap: 12px; margin: 0 0 14px;
  color: var(--kyu-accent); font-family: var(--kyu-body); font-size: 12px; font-weight: 600;
  letter-spacing: .3em; text-transform: uppercase;
}
.kyu-kicker::before, .kyu-kicker::after { content: ""; width: 28px; height: 1px; background: currentColor; opacity: .6; }
.kyu-h2 {
  margin: 0 0 12px; font-family: var(--kyu-display); font-weight: 600;
  font-size: clamp(30px, 4.6vw, 52px); line-height: 1.16; letter-spacing: -.005em; color: var(--kyu-ink);
  text-wrap: balance;
}
.kyu-sub { margin: 0 0 20px; color: var(--kyu-muted); font-size: 15px; }
.kyu-orn { display: block; margin: 0 auto 16px; color: var(--kyu-accent); font-size: 30px; line-height: 1; opacity: .85; }

/* ---------- Lời mở đầu ---------- */
.kyu-lead {
  margin: 6px auto 0; max-width: 30ch; padding: 0; border: 0;
  font-family: var(--kyu-display); font-size: clamp(26px, 3.6vw, 40px); line-height: 1.32; font-style: italic;
  color: var(--kyu-ink); text-wrap: balance;
}
.kyu-stats {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(130px, 1fr)); gap: 14px;
  margin: clamp(32px, 5vw, 52px) auto 0; max-width: 720px;
}
.kyu-stat { padding: 22px 12px 18px; border-radius: 18px; background: var(--kyu-surface); box-shadow: 0 1px 0 rgba(0,0,0,.03), 0 18px 40px -26px rgba(0,0,0,.35); }
.kyu-stat strong {
  display: block; font-family: var(--kyu-display); font-size: clamp(36px, 5vw, 54px); font-weight: 600; line-height: 1.1;
  color: var(--kyu-accent); font-variant-numeric: lining-nums tabular-nums;
}
.kyu-stat span { display: block; margin-top: 6px; color: var(--kyu-muted); font-size: 12px; letter-spacing: .18em; text-transform: uppercase; }

/* ---------- Thầy cô ---------- */
.kyu-card {
  position: relative; padding: clamp(32px, 5vw, 56px) clamp(22px, 5vw, 56px); border-radius: 24px;
  background: var(--kyu-surface); box-shadow: 0 30px 70px -40px rgba(0,0,0,.45);
}
.kyu-card::before { content: "“"; position: absolute; top: -26px; left: 50%; transform: translateX(-50%); font-family: var(--kyu-display); font-size: 88px; line-height: 1; color: var(--kyu-accent); }
.kyu-teacher-note { margin: 0 auto; max-width: 52ch; font-size: 17px; color: var(--kyu-ink); opacity: .9; }

/* ---------- Hành trình ---------- */
.kyu-steps { list-style: none; margin: 36px 0 0; padding: 0; display: grid; gap: 18px; text-align: left; }
.kyu-step { position: relative; padding: 22px 24px; border-radius: 18px; background: var(--kyu-surface); box-shadow: 0 18px 40px -30px rgba(0,0,0,.4); }
.kyu-step .kyu-h3 { margin: 4px 0 6px; font-family: var(--kyu-display); font-size: 24px; font-weight: 600; line-height: 1.25; color: var(--kyu-ink); }
.kyu-step p { margin: 0; color: var(--kyu-muted); font-size: 15.5px; line-height: 1.7; }
.kyu-step-year { font-family: var(--kyu-display); font-size: 15px; font-weight: 600; letter-spacing: .14em; color: var(--kyu-accent); }
/* kiểu "line": trục dọc */
.kyu-t-line .kyu-steps { padding-left: 34px; border-left: 1px solid color-mix(in srgb, var(--kyu-accent) 45%, transparent); gap: 26px; }
.kyu-t-line .kyu-step::before { content: ""; position: absolute; left: -42px; top: 28px; width: 15px; height: 15px; border-radius: 50%; background: var(--kyu-accent); box-shadow: 0 0 0 5px var(--kyu-bg); }
/* kiểu "steps": 3 cột ngang */
.kyu-t-steps .kyu-steps { grid-template-columns: repeat(3, minmax(0, 1fr)); counter-reset: s; text-align: center; }
.kyu-t-steps .kyu-step { padding-top: 46px; }
.kyu-t-steps .kyu-step::before { counter-increment: s; content: counter(s); position: absolute; top: -20px; left: 50%; transform: translateX(-50%); width: 42px; height: 42px; display: grid; place-items: center; border-radius: 50%; background: var(--kyu-accent); color: var(--kyu-surface); font-family: var(--kyu-display); font-size: 20px; font-weight: 600; }
/* kiểu "cards": thẻ nghiêng nhẹ như trang giấy */
.kyu-t-cards .kyu-steps { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.kyu-t-cards .kyu-step:nth-child(1) { transform: rotate(-1.2deg); }
.kyu-t-cards .kyu-step:nth-child(3) { transform: rotate(1.2deg); }

/* ---------- Album ---------- */
.kyu-gallery { margin-top: 32px; }
.kyu-ph { margin: 0; position: relative; overflow: hidden; border-radius: 14px; background: color-mix(in srgb, var(--kyu-ink) 8%, transparent); }
.kyu-ph a { display: block; cursor: zoom-in; }
.kyu.kyu .kyu-ph > a { height: 100%; }
.kyu.kyu .kyu-g-masonry .kyu-ph > a, .kyu.kyu .kyu-g-polaroid .kyu-ph > a { height: auto; }
.kyu-ph img { display: block; aspect-ratio: auto; width: 100%; height: 100%; object-fit: cover; transition: transform 1.1s cubic-bezier(.2,.7,.2,1), filter .6s ease; }
.kyu-ph:hover img { transform: scale(1.05); }
.kyu-ph .kyu-cap { position: absolute; left: 0; right: 0; bottom: 0; padding: 26px 12px 10px; color: #fff; font-size: 13px; text-align: left; background: linear-gradient(transparent, rgba(0,0,0,.55)); }
.kyu-g-masonry .kyu-gallery { columns: 3 220px; column-gap: 14px; }
.kyu-g-masonry .kyu-ph { break-inside: avoid; margin-bottom: 14px; }
.kyu-g-masonry .kyu-ph img { height: auto; }
.kyu-g-mosaic .kyu-gallery { display: grid; grid-auto-flow: dense; grid-template-columns: repeat(4, 1fr); grid-auto-rows: 170px; gap: 12px; }
.kyu-g-mosaic .kyu-ph:nth-child(6n+1) { grid-column: span 2; grid-row: span 2; }
.kyu-g-mosaic .kyu-ph:nth-child(6n+4) { grid-row: span 2; }
.kyu-g-film .kyu-gallery { display: flex; gap: 14px; overflow-x: auto; scroll-snap-type: x mandatory; padding: 18px 4px 22px; scrollbar-width: thin;
  background: repeating-linear-gradient(90deg, transparent 0 14px, color-mix(in srgb, var(--kyu-ink) 18%, transparent) 14px 22px) top/100% 8px no-repeat,
              repeating-linear-gradient(90deg, transparent 0 14px, color-mix(in srgb, var(--kyu-ink) 18%, transparent) 14px 22px) bottom/100% 8px no-repeat; }
.kyu-g-film .kyu-ph { flex: 0 0 min(320px, 76vw); aspect-ratio: 4/5; scroll-snap-align: center; border-radius: 6px; }
.kyu-g-polaroid .kyu-gallery { display: flex; flex-wrap: wrap; justify-content: center; gap: 22px; }
.kyu-g-polaroid .kyu-ph { width: min(230px, 42vw); padding: 10px 10px 40px; border-radius: 3px; background: #fff; box-shadow: 0 14px 30px -14px rgba(0,0,0,.45); overflow: visible; }
.kyu-g-polaroid .kyu-ph img { aspect-ratio: 1/1; height: auto; }
.kyu-g-polaroid .kyu-ph:nth-child(odd) { transform: rotate(-2.5deg); }
.kyu-g-polaroid .kyu-ph:nth-child(even) { transform: rotate(2deg); }
.kyu-g-polaroid .kyu-ph:hover { transform: rotate(0) scale(1.04); z-index: 2; transition: transform .4s ease; }
.kyu-g-polaroid .kyu-ph .kyu-cap { background: none; color: #444; top: auto; bottom: 8px; padding: 0 12px; font-family: 'Patrick Hand', cursive; font-size: 16px; text-align: center; }
.kyu-g-stack .kyu-gallery { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.kyu-g-stack .kyu-ph { aspect-ratio: 3/4; border: 8px solid var(--kyu-surface); box-shadow: 0 20px 40px -24px rgba(0,0,0,.5); }

/* ---------- Tường lời nhắn ---------- */
.kyu-notes { margin-top: 30px; display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 18px; text-align: left; }
.kyu-note { margin: 0; padding: 22px 22px 18px; border-radius: 16px; background: var(--kyu-surface); box-shadow: 0 18px 40px -28px rgba(0,0,0,.45); }
.kyu-note .kyu-q { margin: 0 0 12px; padding: 0; border: 0; font-size: 16px; line-height: 1.7; color: var(--kyu-ink); }
.kyu-note .kyu-cap { color: var(--kyu-accent); font-size: 14px; font-weight: 600; }
.kyu-w-notes .kyu-note { border-radius: 2px; background: color-mix(in srgb, var(--kyu-accent) 14%, #fffbe6); font-family: 'Patrick Hand', var(--kyu-body); font-size: 18px; }
.kyu-w-notes .kyu-note:nth-child(3n+1) { transform: rotate(-1.6deg); }
.kyu-w-notes .kyu-note:nth-child(3n+2) { transform: rotate(1.2deg); background: color-mix(in srgb, var(--kyu-accent) 10%, #eef7ff); }
.kyu-w-letters .kyu-note { border-top: 3px solid var(--kyu-accent); border-radius: 4px 4px 16px 16px; }
.kyu-w-letters .kyu-note .kyu-q { font-family: var(--kyu-display); font-size: 19px; font-style: italic; }
.kyu-w-quotes .kyu-notes { grid-template-columns: 1fr; max-width: 720px; margin-inline: auto; text-align: center; }
.kyu-w-quotes .kyu-note { background: transparent; box-shadow: none; border-bottom: 1px solid color-mix(in srgb, var(--kyu-ink) 14%, transparent); border-radius: 0; padding: 26px 8px; }
.kyu-w-quotes .kyu-note .kyu-q { font-family: var(--kyu-display); font-size: clamp(20px, 2.6vw, 26px); font-style: italic; line-height: 1.5; }
.kyu-w-bubbles .kyu-note { border-radius: 22px 22px 22px 6px; }
.kyu-w-bubbles .kyu-note:nth-child(even) { border-radius: 22px 22px 6px 22px; background: color-mix(in srgb, var(--kyu-accent) 16%, var(--kyu-surface)); }

/* ---------- Lời hẹn ---------- */
.kyu-close { margin: 0 auto; max-width: 26ch; font-family: var(--kyu-display); font-size: clamp(28px, 4.2vw, 48px); line-height: 1.28; color: var(--kyu-ink); text-wrap: balance; }
.kyu-sign { margin: 18px 0 0; color: var(--kyu-muted); font-size: 15px; letter-spacing: .06em; }

/* ---------- Phong cách khối ---------- */
.kyu-s-dark .kyu-stat, .kyu-s-dark .kyu-card, .kyu-s-dark .kyu-step, .kyu-s-dark .kyu-note:not(.kyu-w-quotes .kyu-note) {
  background: color-mix(in srgb, var(--kyu-surface) 88%, transparent); border: 1px solid color-mix(in srgb, var(--kyu-accent) 22%, transparent); box-shadow: 0 30px 60px -40px rgba(0,0,0,.8);
}
.kyu-s-dark .kyu-w-notes .kyu-note { background: color-mix(in srgb, var(--kyu-accent) 18%, var(--kyu-surface)); }
.kyu-s-glass .kyu-stat, .kyu-s-glass .kyu-card, .kyu-s-glass .kyu-step, .kyu-s-glass .kyu-note {
  background: color-mix(in srgb, var(--kyu-surface) 62%, transparent); backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px);
  border: 1px solid color-mix(in srgb, #fff 60%, transparent);
}
.kyu-s-frame .kyu-stat, .kyu-s-frame .kyu-card, .kyu-s-frame .kyu-step, .kyu-s-frame .kyu-note {
  border-radius: 4px; box-shadow: none; border: 1px solid color-mix(in srgb, var(--kyu-ink) 18%, transparent); outline: 1px solid color-mix(in srgb, var(--kyu-ink) 8%, transparent); outline-offset: 5px;
}
.kyu-s-pastel .kyu-stat, .kyu-s-pastel .kyu-card, .kyu-s-pastel .kyu-step, .kyu-s-pastel .kyu-note { border-radius: 26px; }
.kyu-s-paper .kyu-card, .kyu-s-paper .kyu-step, .kyu-s-paper .kyu-stat {
  background-image: repeating-linear-gradient(transparent 0 31px, color-mix(in srgb, var(--kyu-accent) 9%, transparent) 31px 32px);
}
.kyu-s-ink .kyu-stat, .kyu-s-ink .kyu-card, .kyu-s-ink .kyu-step, .kyu-s-ink .kyu-note { border-radius: 2px; box-shadow: none; border-left: 3px solid var(--kyu-ink); }

/* ---------- Chuyển động khi cuộn (chỉ bật khi JS chạy) ---------- */
.kyu-js [data-kyu-reveal] { opacity: 0; transition: opacity .9s ease, transform .9s cubic-bezier(.2,.7,.2,1), filter .9s ease; transition-delay: calc(var(--i, 0) * 90ms); }
.kyu-js.kyu-m-rise [data-kyu-reveal] { transform: translateY(28px); }
.kyu-js.kyu-m-blur [data-kyu-reveal] { filter: blur(10px); transform: translateY(12px); }
.kyu-js.kyu-m-slide [data-kyu-reveal] { transform: translateX(-36px); }
.kyu-js.kyu-m-zoom [data-kyu-reveal] { transform: scale(.94); }
.kyu-js [data-kyu-reveal].is-in { opacity: 1; filter: none; transform: none; }
.kyu-js .kyu-t-cards .kyu-step.is-in:nth-child(1) { transform: rotate(-1.2deg); }
.kyu-js .kyu-t-cards .kyu-step.is-in:nth-child(3) { transform: rotate(1.2deg); }
.kyu-js .kyu-g-polaroid .kyu-ph.is-in:nth-child(odd) { transform: rotate(-2.5deg); }
.kyu-js .kyu-g-polaroid .kyu-ph.is-in:nth-child(even) { transform: rotate(2deg); }
.kyu-js .kyu-w-notes .kyu-note.is-in:nth-child(3n+1) { transform: rotate(-1.6deg); }
.kyu-js .kyu-w-notes .kyu-note.is-in:nth-child(3n+2) { transform: rotate(1.2deg); }
@media (prefers-reduced-motion: reduce) { .kyu-js [data-kyu-reveal] { opacity: 1 !important; transform: none !important; filter: none !important; transition: none !important; } }

/* Thanh tiến độ đọc + xem ảnh phóng to */
.kyu-progress { position: fixed; top: 0; left: 0; z-index: 9998; height: 3px; width: 100%; transform-origin: left; transform: scaleX(0); background: var(--kyu-accent); pointer-events: none; }
.kyu-lb { position: fixed; inset: 0; z-index: 10000; display: grid; place-items: center; padding: 24px; background: rgba(10,8,6,.88); opacity: 0; pointer-events: none; transition: opacity .3s ease; }
.kyu-lb.is-open { opacity: 1; pointer-events: auto; }
.kyu-lb img { max-width: min(1100px, 100%); max-height: 86vh; border-radius: 8px; box-shadow: 0 30px 80px rgba(0,0,0,.6); transform: scale(.96); transition: transform .35s ease; }
.kyu-lb.is-open img { transform: none; }
.kyu-lb button { position: absolute; top: 14px; right: 16px; width: 44px; height: 44px; border: 0; border-radius: 50%; background: rgba(255,255,255,.14); color: #fff; font-size: 22px; cursor: pointer; }
.kyu-lb .kyu-lb-prev, .kyu-lb .kyu-lb-next { top: 50%; transform: translateY(-50%); }
.kyu-lb .kyu-lb-prev { left: 12px; right: auto; }
.kyu-lb .kyu-lb-next { right: 12px; }

/* ---------- Điện thoại ---------- */
@media (max-width: 760px) {
  .kyu { font-size: 16px; }
  .kyu-ch { padding: 44px 16px; }
  .kyu-stats { grid-template-columns: repeat(2, 1fr); gap: 10px; }
  .kyu-t-steps .kyu-steps, .kyu-t-cards .kyu-steps { grid-template-columns: 1fr; gap: 28px; }
  .kyu-t-cards .kyu-step { transform: none !important; }
  .kyu-g-mosaic .kyu-gallery { grid-template-columns: repeat(2, 1fr); grid-auto-rows: 150px; }
  .kyu-g-stack .kyu-gallery { grid-template-columns: repeat(2, 1fr); }
  .kyu-g-masonry .kyu-gallery { columns: 2 140px; column-gap: 10px; }
  .kyu-g-polaroid .kyu-gallery { gap: 14px; }
  .kyu-notes { grid-template-columns: 1fr; }
}

/* Hiện dần cho mục gốc của theme chưa có hiệu ứng riêng (lớp do nang-cap.js gắn) */
.kyu-tr { opacity: 0; transform: translateY(26px); transition: opacity .9s ease, transform .9s cubic-bezier(.2,.7,.2,1); }
.kyu-tr.kyu-tr-in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) { .kyu-tr { opacity: 1 !important; transform: none !important; } }

/* =====================================================================
   Màn mở đầu · Lá thư · Đếm ngày · Lời cảm ơn cuối · Hiệu ứng không khí
   ===================================================================== */
.kyu-intro {
  position: fixed; inset: 0; z-index: 100000; display: grid; place-items: center; overflow: hidden;
  background: var(--kyu-bg); color: #fff; text-align: center;
  transition: opacity 1.1s ease, visibility 1.1s ease;
}
.kyu-intro.is-out { opacity: 0; visibility: hidden; pointer-events: none; }
.kyu-intro-bg { position: absolute; inset: -4%; background-size: cover; background-position: center; animation: kyuKen 18s ease-out both; }
@keyframes kyuKen { from { transform: scale(1.12) translateY(1.5%); } to { transform: scale(1); } }
.kyu-intro-veil { position: absolute; inset: 0; background:
  radial-gradient(120% 90% at 50% 40%, transparent 0%, rgba(0,0,0,.35) 60%, rgba(0,0,0,.72) 100%),
  linear-gradient(180deg, color-mix(in srgb, var(--kyu-bg) 35%, transparent), color-mix(in srgb, var(--kyu-bg) 85%, transparent)); }
.kyu-intro.kyu-s-paper .kyu-intro-veil, .kyu-intro.kyu-s-pastel .kyu-intro-veil, .kyu-intro.kyu-s-glass .kyu-intro-veil, .kyu-intro.kyu-s-frame .kyu-intro-veil, .kyu-intro.kyu-s-ink .kyu-intro-veil {
  background: radial-gradient(120% 90% at 50% 40%, rgba(0,0,0,.08) 0%, rgba(0,0,0,.45) 70%, rgba(0,0,0,.7) 100%); }
.kyu-intro-inner { position: relative; z-index: 2; max-width: 760px; padding: 32px 22px; }
.kyu-intro-inner > * { opacity: 0; transform: translateY(18px); animation: kyuUp 1.2s cubic-bezier(.2,.7,.2,1) forwards; }
.kyu-intro-inner > :nth-child(1) { animation-delay: .2s; }
.kyu-intro-inner > :nth-child(2) { animation-delay: .5s; }
.kyu-intro-inner > :nth-child(3) { animation-delay: .8s; }
.kyu-intro-inner > :nth-child(4) { animation-delay: 1.15s; }
.kyu-intro-inner > :nth-child(5) { animation-delay: 1.5s; }
.kyu-intro-inner > :nth-child(6) { animation-delay: 1.9s; }
.kyu-intro-inner > :nth-child(7) { animation-delay: 2.2s; }
@keyframes kyuUp { to { opacity: 1; transform: none; } }
.kyu-intro .kyu-orn { color: #fff; opacity: .9; font-size: 34px; }
.kyu-intro-kicker { margin: 0 0 18px; font-family: var(--kyu-body); font-size: 12px; font-weight: 600; letter-spacing: .38em; text-transform: uppercase; color: rgba(255,255,255,.85); }
.kyu-intro-title { margin: 0; font-family: var(--kyu-display); font-weight: 600; font-size: clamp(64px, 13vw, 168px); line-height: 1.02; letter-spacing: -.01em; color: #fff; text-shadow: 0 6px 40px rgba(0,0,0,.35); }
.kyu-intro-years { margin: 10px 0 0; font-family: var(--kyu-display); font-style: italic; font-size: clamp(20px, 2.6vw, 28px); color: rgba(255,255,255,.9); }
.kyu-intro-line { margin: 26px auto 34px; max-width: 34ch; font-family: var(--kyu-display); font-style: italic; font-size: clamp(18px, 2.2vw, 23px); line-height: 1.55; color: rgba(255,255,255,.88); text-wrap: balance; }
.kyu-intro-btn {
  position: relative; display: inline-flex; align-items: center; gap: 10px; min-height: 56px; padding: 0 38px; border-radius: 999px;
  border: 1px solid rgba(255,255,255,.65); background: rgba(255,255,255,.12); color: #fff; cursor: pointer;
  font-family: var(--kyu-body); font-size: 15px; font-weight: 600; letter-spacing: .14em; text-transform: uppercase;
  backdrop-filter: blur(8px); -webkit-backdrop-filter: blur(8px); transition: background .3s ease, transform .3s ease, box-shadow .3s ease;
}
.kyu-intro-btn::after { content: ""; position: absolute; inset: -7px; border-radius: inherit; border: 1px solid rgba(255,255,255,.35); animation: kyuPulse 2.4s ease-out infinite; }
@keyframes kyuPulse { from { opacity: .9; transform: scale(.96); } to { opacity: 0; transform: scale(1.14); } }
.kyu-intro-btn:hover { background: #fff; color: var(--kyu-ink); transform: translateY(-2px); box-shadow: 0 16px 40px -14px rgba(0,0,0,.5); }
.kyu-intro-hint { margin: 16px 0 0; font-size: 13px; color: rgba(255,255,255,.72); letter-spacing: .04em; }
@media (prefers-reduced-motion: reduce) { .kyu-intro-bg, .kyu-intro-inner > *, .kyu-intro-btn::after { animation: none !important; opacity: 1; transform: none; } }

/* Đếm ngày */
.kyu-days { margin: 28px auto 0; max-width: 40ch; color: var(--kyu-muted); font-family: var(--kyu-display); font-style: italic; font-size: 19px; }
.kyu-days strong { display: inline-block; margin: 0 6px; color: var(--kyu-accent); font-style: normal; font-size: 1.6em; font-variant-numeric: tabular-nums lining-nums; }

/* Lá thư gửi tương lai */
.kyu-letter {
  position: relative; margin: 26px auto 0; max-width: 640px; padding: clamp(34px, 6vw, 64px) clamp(26px, 6vw, 64px);
  text-align: left; background: var(--kyu-surface); border-radius: 6px;
  box-shadow: 0 1px 0 rgba(0,0,0,.04), 0 40px 80px -46px rgba(0,0,0,.55);
  background-image: repeating-linear-gradient(transparent 0 35px, color-mix(in srgb, var(--kyu-accent) 12%, transparent) 35px 36px);
  background-position: 0 22px;
}
.kyu-letter::before { content: ""; position: absolute; top: 0; bottom: 0; left: clamp(18px, 4vw, 40px); width: 1px; background: color-mix(in srgb, var(--kyu-accent) 35%, transparent); }
.kyu-letter p { margin: 0 0 14px; font-family: 'Patrick Hand', var(--kyu-display); font-size: clamp(19px, 2.2vw, 22px); line-height: 36px; color: var(--kyu-ink); }
.kyu-letter .kyu-letter-to { font-size: clamp(22px, 2.6vw, 26px); color: var(--kyu-accent); }
.kyu-letter .kyu-letter-sign { margin-top: 26px; text-align: right; }
.kyu-letter .kyu-letter-sign strong { font-family: var(--kyu-display); font-size: 1.15em; }
.kyu-letter .kyu-letter-sign span { color: var(--kyu-muted); font-size: .85em; }
.kyu-s-dark .kyu-letter { background-color: color-mix(in srgb, var(--kyu-surface) 92%, #000); border: 1px solid color-mix(in srgb, var(--kyu-accent) 25%, transparent); }
.kyu-type-hide { visibility: hidden; }
.kyu-caret::after { content: "▍"; margin-left: 1px; color: var(--kyu-accent); animation: kyuBlink 1s steps(1) infinite; }
@keyframes kyuBlink { 50% { opacity: 0; } }

/* Lời cảm ơn cuối (cuộn tên như cuối phim) */
.kyu-credits { margin: 44px auto 0; max-width: 420px; }
.kyu-credits-title { margin: 0 0 14px; color: var(--kyu-muted); font-size: 13px; letter-spacing: .2em; text-transform: uppercase; }
.kyu-credits-roll { height: 150px; overflow: hidden; -webkit-mask-image: linear-gradient(transparent, #000 25%, #000 75%, transparent); mask-image: linear-gradient(transparent, #000 25%, #000 75%, transparent); }
.kyu-credits-track { display: flex; flex-direction: column; gap: 10px; animation: kyuRoll 22s linear infinite; }
.kyu-credits-track span { font-family: var(--kyu-display); font-size: 22px; color: var(--kyu-ink); }
@keyframes kyuRoll { from { transform: translateY(0); } to { transform: translateY(-50%); } }
@media (prefers-reduced-motion: reduce) { .kyu-credits-track { animation: none; } .kyu-credits-roll { height: auto; -webkit-mask-image: none; mask-image: none; } }

/* Lớp vân giấy / hạt phim (rất nhẹ) */
.kyu-s-paper::before, .kyu-s-ink::before, .kyu-s-frame::before, .kyu-s-dark::before {
  content: ""; position: absolute; inset: 0; z-index: -1; pointer-events: none; opacity: .5;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='160' height='160'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.9' numOctaves='2' stitchTiles='stitch'/%3E%3CfeColorMatrix values='0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 .08 0'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}
.kyu-s-dark::before { opacity: .8; mix-blend-mode: screen; }

/* Đường phân cách có hoạ tiết giữa các chương */
.kyu-ch + .kyu-ch::before { content: none; }
.kyu.kyu .kyu-ch + .kyu-ch > .kyu-wrap::before { content: ""; display: block; width: 120px; height: 1px; margin: 0 auto clamp(36px, 5vw, 64px); background: linear-gradient(90deg, transparent, var(--kyu-accent), transparent); opacity: .55; }
.kyu.kyu .kyu-teacher > .kyu-wrap::before { display: none; }

/* Lời mở đầu: chữ hoa lớn */
.kyu-lead::first-letter { font-size: 1.9em; line-height: .8; color: var(--kyu-accent); font-style: normal; }

/* Canvas hiệu ứng không khí */
.kyu-fx { position: fixed; inset: 0; z-index: 3; pointer-events: none; opacity: .85; }

/* Nút quay lại trang chọn theme (chỉ ở lớp mẫu) */
.kyu-back {
  position: fixed; top: 14px; left: 14px; z-index: 100001;
  display: inline-flex; align-items: center; gap: 8px; min-height: 40px; padding: 0 16px 0 12px; border-radius: 999px;
  background: rgba(20, 18, 16, .62); color: #fff !important; text-decoration: none !important;
  font: 500 13px/1 'Be Vietnam Pro', system-ui, sans-serif; letter-spacing: .02em;
  backdrop-filter: blur(10px); -webkit-backdrop-filter: blur(10px); box-shadow: 0 8px 24px -10px rgba(0,0,0,.5);
  transition: background .25s ease, transform .25s ease;
}
.kyu-back span { font-size: 16px; }
.kyu-back b { font-weight: 700; color: #f1d9a5; }
.kyu-back:hover { background: rgba(20, 18, 16, .85); transform: translateX(-2px); }
@media (max-width: 760px) { .kyu-back { top: 10px; left: 10px; min-height: 36px; font-size: 12px; } }

/* Thang cỡ chữ thống nhất (bản 2) — cùng nhịp với trang thiệp & catalogue */
.kyu.kyu .kyu-h2 { font-size: clamp(28px, 3.4vw, 42px); }
.kyu.kyu .kyu-lead { font-size: clamp(22px, 2.8vw, 32px); }
.kyu.kyu .kyu-close { font-size: clamp(24px, 3.2vw, 38px); }
.kyu-intro .kyu-intro-title { font-size: clamp(56px, 10vw, 128px); }