/* ==========================================================
   learn.css — phần RIÊNG của learn.html (Trạm Tri Thức).

   Khung chung (tokens, nền, .wrap, header .hub-top, .hero, .currency,
   .lang-switch, .toast) ở css/page-shell.css — nạp trước file này.
   Trước 29/07/2026 file này có bản copy riêng của toàn bộ phần đó, và header
   mang class `.top` riêng thay vì `.hub-top` dùng chung.
   ========================================================== */

/* Tiêu đề trang có chữ gradient — chỉ trang này dùng, nên ở đây. */
.htitle{flex:1;min-width:180px;font-family:var(--font-display);font-weight:700;font-size:clamp(15px,2.4vw,21px);letter-spacing:.02em;
  background:linear-gradient(120deg,#fff,var(--cyan),var(--purple));-webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent;
  text-shadow:0 2px 20px rgba(95,150,255,.25);}

/* Hero của trang này thấp và nhỏ hơn khung chung: ngay dưới nó là 2 thẻ chế độ
   to, để hero cao bằng khung chung thì phải cuộn mới thấy thẻ. */
.hero{padding:22px 0 4px;}
.hero .eyebrow{font-size:11px;}
.hero p{font-size:14px;max-width:560px;}
/* ============ 2 MODE CARDS ============ */
/* ⚠️ HAI thẻ (04/08/2026): MOD-C Sổ Tay Thuật Ngữ đã chuyển lên dashboard, thay
   chỗ MOD-06 "Thư Viện Thiên Văn". Lưới vì thế trở lại tối đa 2 cột — để
   `repeat(3,1fr)` với hai thẻ thì chúng co lại còn 2/3 hàng và chừa một khoảng
   trống bên phải, trông như thẻ thứ ba tải hỏng.
   Thêm thẻ thứ ba thì nhớ mở lại nấc 900px → 3 cột (đừng để 2 cột: thẻ lẻ sẽ nằm
   một mình một hàng rộng gấp đôi). */
.modes{display:grid;grid-template-columns:1fr;gap:22px;margin-top:26px;}
@media(min-width:600px){.modes{grid-template-columns:1fr 1fr;}}
@media(max-width:680px){.modes{grid-template-columns:1fr;}}
.mode{position:relative;display:flex;flex-direction:column;border-radius:20px;padding:26px 24px;overflow:hidden;
  --neon:rgba(56,189,248,.4); --neonS:rgba(56,189,248,.9);
  border:1px solid var(--neon);background:linear-gradient(180deg, rgba(15,23,42,.62), rgba(15,23,42,.5));
  -webkit-backdrop-filter:blur(16px);backdrop-filter:blur(16px);
  box-shadow:0 24px 54px -26px rgba(0,0,0,.75), 0 0 30px -8px var(--neon), inset 0 0 40px -18px var(--neonS);
  transition:transform .35s var(--jelly),box-shadow .35s var(--ease),border-color .35s var(--ease);}
.mode:hover{transform:translateY(-8px) scale(1.015);border-color:var(--neonS);
  box-shadow:0 34px 70px -24px rgba(0,0,0,.8), 0 0 50px -2px var(--neonS), inset 0 0 46px -14px var(--neonS);}
.mode::before{content:"";position:absolute;inset:0;pointer-events:none;opacity:.5;border-radius:inherit;
  background-image:linear-gradient(rgba(120,160,255,.06) 1px,transparent 1px),linear-gradient(90deg,rgba(120,160,255,.06) 1px,transparent 1px);
  background-size:24px 24px;-webkit-mask:linear-gradient(180deg,#000,transparent 80%);mask:linear-gradient(180deg,#000,transparent 80%);}
.mode .hud-line{display:flex;align-items:center;justify-content:space-between;font-family:var(--font-mono);font-size:9.5px;letter-spacing:.14em;color:var(--ink-faint);text-transform:uppercase;margin-bottom:14px;}
.mode .hud-line .led{width:8px;height:8px;border-radius:50%;background:var(--green);box-shadow:0 0 8px var(--green);animation:blink 1.6s steps(1,end) infinite;margin-right:6px;}
.mode .m-ic{width:64px;height:64px;border-radius:18px;display:grid;place-items:center;font-size:30px;color:var(--neonS);
  background:var(--ic-bg,rgba(56,189,248,.16));border:1px solid var(--neon);box-shadow:inset 0 0 18px -6px var(--neon);margin-bottom:16px;transition:transform .35s var(--jelly);}
.mode:hover .m-ic{transform:scale(1.1) rotate(-6deg);}
.mode .m-tag{font-family:var(--font-mono);font-size:10px;letter-spacing:.16em;text-transform:uppercase;color:var(--ink-faint);}
.mode h2{font-family:var(--font-display);font-weight:700;font-size:22px;margin:5px 0 0;}
.mode p{color:var(--ink-soft);font-size:13.5px;line-height:1.55;margin:11px 0 18px;flex:1;}
.mode .m-btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;cursor:pointer;border:none;width:100%;
  padding:14px 18px;border-radius:14px;font-family:var(--font-display);font-weight:600;font-size:15px;color:#04060f;
  background:linear-gradient(120deg,var(--cyan),#2f80ed);box-shadow:0 12px 26px -12px rgba(56,189,248,.7);transition:transform .3s var(--jelly),filter .2s;}
.mode .m-btn:hover{filter:brightness(1.07);transform:translateY(-2px);}
.mode .m-btn:active{transform:scale(.94);}
.mode--lib {--neon:rgba(56,189,248,.4);--neonS:rgba(56,189,248,.9);--ic-bg:rgba(56,189,248,.16);}
.mode--quiz{--neon:rgba(192,132,252,.42);--neonS:rgba(192,132,252,.95);--ic-bg:rgba(192,132,252,.18);}
.mode--quiz .m-btn{background:linear-gradient(120deg,var(--purple),#8f7bff);box-shadow:0 12px 26px -12px rgba(192,132,252,.7);}

/* ============ FEATURED ARTICLES ============ */
.feat-head{display:flex;align-items:center;justify-content:space-between;gap:10px;margin:38px 0 4px;}
.feat-head .ft{font-family:var(--font-mono);font-size:11px;letter-spacing:.18em;text-transform:uppercase;color:var(--cyan);}
.feat-head .fs{font-family:var(--font-mono);font-size:9.5px;letter-spacing:.12em;color:var(--ink-faint);}
.articles{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:20px;margin-top:16px;}
.art{position:relative;display:flex;flex-direction:column;border-radius:16px;overflow:hidden;cursor:pointer;
  border:1px solid var(--brd);background:rgba(15,23,42,.5);-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);
  box-shadow:0 18px 44px -24px rgba(0,0,0,.7);transition:transform .3s var(--jelly),border-color .25s,box-shadow .25s;}
.art:hover{transform:translateY(-6px);border-color:rgba(56,189,248,.6);box-shadow:0 26px 54px -22px rgba(0,0,0,.8),0 0 26px -8px rgba(56,189,248,.5);}
.art .thumb{position:relative;height:132px;overflow:hidden;}
.art .thumb .celest{position:absolute;width:120px;height:120px;border-radius:50%;left:50%;top:56%;transform:translate(-50%,-50%);
  background:radial-gradient(circle at 38% 32%, var(--c1), var(--c2) 55%, var(--c3) 100%);box-shadow:0 0 40px -4px var(--c1);}
.art .thumb .em{position:absolute;left:50%;top:50%;transform:translate(-50%,-50%);font-size:44px;filter:drop-shadow(0 4px 10px rgba(0,0,0,.5));}
.art .thumb::after{content:"";position:absolute;inset:0;background:
  radial-gradient(1px 1px at 20% 30%,#fff,transparent),radial-gradient(1px 1px at 70% 60%,#dbeaff,transparent),radial-gradient(1px 1px at 45% 80%,#fff,transparent);
  opacity:.7;}
.art .src{position:absolute;top:10px;left:10px;z-index:2;display:inline-flex;align-items:center;gap:5px;
  font-family:var(--font-mono);font-size:9px;letter-spacing:.1em;color:#cfe8ff;background:rgba(6,10,22,.7);border:1px solid rgba(120,180,255,.4);
  padding:4px 9px;border-radius:999px;-webkit-backdrop-filter:blur(4px);backdrop-filter:blur(4px);}
.art .body{padding:13px 14px 15px;display:flex;flex-direction:column;flex:1;}
.art .body h3{font-family:var(--font-display);font-weight:600;font-size:14.5px;line-height:1.35;margin:0;color:#fff;}
.art .body .r{display:inline-flex;align-items:center;gap:6px;margin-top:12px;align-self:flex-start;
  font-family:var(--font-display);font-weight:700;font-size:13px;color:var(--purple);
  background:rgba(192,132,252,.12);border:1px solid rgba(192,132,252,.4);padding:4px 10px;border-radius:999px;}
.art .body .r img{width:14px;height:14px;object-fit:contain;}
.art .body .r.done{color:var(--green);background:rgba(74,222,128,.12);border-color:rgba(74,222,128,.4);}

/* ============ READER MODAL ============ */
.modal{z-index:60;padding:18px;background:rgba(4,6,20,.7);-webkit-backdrop-filter:blur(8px);backdrop-filter:blur(8px);transition:opacity .3s;}
.reader-card{width:100%;max-width:560px;max-height:88vh;overflow:auto;border-radius:22px;position:relative;
  background:linear-gradient(180deg, rgba(16,22,40,.98), rgba(11,15,25,.99));border:1px solid rgba(56,189,248,.45);
  box-shadow:0 28px 70px -26px rgba(0,0,0,.9), 0 0 46px -12px rgba(56,189,248,.5);
  transform:translateY(12px) scale(.97);transition:transform .35s var(--jelly);}
.modal.show .reader-card{transform:none;}
.reader-close{position:absolute;top:12px;right:12px;z-index:3;width:34px;height:34px;border-radius:10px;cursor:pointer;
  border:1px solid var(--brd);background:rgba(9,14,28,.7);color:var(--ink);font-size:15px;transition:background .18s,transform .12s;}
.reader-close:hover{background:rgba(255,255,255,.12);} .reader-close:active{transform:scale(.9);}
.reader-thumb{position:relative;height:170px;overflow:hidden;border-radius:22px 22px 0 0;}
.reader-thumb .celest{position:absolute;width:180px;height:180px;border-radius:50%;left:50%;top:60%;transform:translate(-50%,-50%);
  background:radial-gradient(circle at 38% 32%, var(--c1), var(--c2) 55%, var(--c3) 100%);box-shadow:0 0 60px -6px var(--c1);}
.reader-thumb .em{position:absolute;left:50%;top:48%;transform:translate(-50%,-50%);font-size:64px;filter:drop-shadow(0 6px 14px rgba(0,0,0,.55));}
.reader-thumb::after{content:"";position:absolute;inset:0;background:linear-gradient(180deg,transparent 40%,rgba(11,15,25,.9));}
.reader-src{position:absolute;top:12px;left:14px;z-index:2;display:inline-flex;align-items:center;gap:5px;
  font-family:var(--font-mono);font-size:10px;letter-spacing:.1em;color:#cfe8ff;background:rgba(6,10,22,.72);border:1px solid rgba(120,180,255,.45);padding:5px 11px;border-radius:999px;}
.reader-in{padding:6px 24px 22px;}
.reader-in h2{font-family:var(--font-display);font-weight:700;font-size:21px;line-height:1.3;margin:8px 0 0;}
.reader-body{color:var(--ink-soft);font-size:14.5px;line-height:1.65;margin:14px 0 0;}
.reader-body p{margin:0 0 11px;}
.reader-note{font-family:var(--font-mono);font-size:10px;letter-spacing:.04em;color:var(--ink-faint);margin-top:6px;}
.reader-link{display:inline-flex;align-items:center;gap:6px;margin-top:12px;font-family:var(--font-mono);font-size:12px;color:var(--cyan);
  border:1px solid rgba(56,189,248,.4);border-radius:10px;padding:8px 12px;transition:background .18s;}
.reader-link:hover{background:rgba(56,189,248,.12);}
.reader-claim{margin-top:18px;width:100%;cursor:pointer;border:none;padding:14px;border-radius:14px;font-family:var(--font-display);font-weight:700;font-size:15px;color:#04060f;
  display:inline-flex;align-items:center;justify-content:center;gap:8px;background:linear-gradient(120deg,var(--cyan),var(--purple));box-shadow:0 12px 26px -12px rgba(56,189,248,.8);transition:transform .25s var(--jelly),filter .2s,opacity .2s;}
.reader-claim img{width:18px;height:18px;object-fit:contain;}
.reader-claim:hover:not(:disabled){filter:brightness(1.08);transform:translateY(-2px);}
.reader-claim:active:not(:disabled){transform:scale(.95);}
.reader-claim:disabled{opacity:.5;cursor:not-allowed;filter:grayscale(.3);box-shadow:none;}
.reader-claim.done{background:rgba(74,222,128,.16);color:var(--green);border:1px solid rgba(74,222,128,.5);}

/* Toast cao hơn khung chung vì header trang này thấp hơn. */
.toast{top:74px;z-index:80;}