/* =========================================================================
   library.css — shared styles for index.html / series.html / book.html
   Signature idea: book series are literally rendered as "book covers" with
   a spine flap, sitting in a library grid — grounded in what the site is.
   ========================================================================= */

:root{
  --brand:#2957a4;--brand2:#5bb3e4;--sun:#ee9d33;
  --paper:#f6f7fb;--ink:#111827;--muted:#64748b;--card:#fff;--line:#e6e9f0;
  --correct:#007d78;--correct-bg:#e0f2f1;--correct-ink:#005f5a;
  --wrong:#c1447e;--wrong-bg:#fce8f1;--wrong-ink:#96305f;
  /* per-page accent, overridden by JS on series.html / book.html */
  --accent:#2957a4;--accent2:#5bb3e4;
  --radius-xl:28px;--radius-lg:22px;--radius-md:18px;--radius-sm:12px;
  --shadow-sm:0 1px 2px rgba(17,24,39,.05),0 1px 1px rgba(17,24,39,.03);
  --shadow-md:0 10px 26px -14px rgba(17,24,39,.22);
  --shadow-lg:0 24px 48px -20px rgba(17,24,39,.28);
}
/* ---------- Dark mode (site-wide toggle, theme.js) ---------- */
:root[data-theme="dark"]{
  --paper:#0e1626;--card:#182338;--ink:#eaf0fb;--muted:#9db0d0;--line:#2b3a58;
  --correct:#3fcfc0;--correct-bg:#0f322e;--correct-ink:#8fe8dd;
  --wrong:#ff8ec0;--wrong-bg:#3a1730;--wrong-ink:#ffb8d8;
  color-scheme:dark;
}
*{box-sizing:border-box}
body{margin:0;background:var(--paper);color:var(--ink);font-family:'Be Vietnam Pro',system-ui,sans-serif;line-height:1.6;
  -webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}
.wrap{max-width:1180px;margin:0 auto;padding:0 20px 64px}
a{text-decoration:none}
@media (prefers-reduced-motion:reduce){*{transition:none!important;animation:none!important}}

/* ---------- sticky top bar (index.html) ---------- */
.site-topbar{
  position:sticky;top:0;z-index:40;display:flex;align-items:center;gap:14px;
  padding:14px 20px;margin:0 0 22px;   /* body-level element: a negative
     margin here has no container padding to cancel and just pushes the
     bar ~20px past the right edge, giving every page a sliver of
     horizontal scroll. */
  background:color-mix(in srgb, var(--paper) 82%, transparent);backdrop-filter:blur(10px);-webkit-backdrop-filter:blur(10px);
  border-bottom:1px solid var(--line);
}
.site-topbar .brand{display:flex;align-items:center;gap:9px;font-family:'Plus Jakarta Sans',system-ui,sans-serif;font-weight:800;color:var(--ink);font-size:1.05rem}
.site-topbar .brand .mark{font-size:1.3rem}
/* ".com" rides smaller and lighter than the site name it follows. */
.site-topbar .brand .brand-tld{font-size:.72em;font-weight:700;opacity:.62;letter-spacing:0;
  margin-left:-9px}  /* .brand is a flex row with gap:9px, which would
     otherwise detach ".com" from the name; cancel it so the brand reads
     as the domain it is. */
.site-topbar-spacer{flex:1}
.site-topbar .tb-link{font-size:.88rem;font-weight:700;color:var(--muted);padding:8px 12px;border-radius:10px}
.site-topbar .tb-link:hover{background:var(--card);color:var(--brand)}
.site-topbar .tb-cta{font-size:.88rem;font-weight:800;color:#fff;background:linear-gradient(150deg,var(--brand2),var(--brand));padding:9px 16px;border-radius:10px;box-shadow:var(--shadow-sm)}

/* ---------- home layout: main content + sidebar, side-by-side on desktop ---------- */
.home-grid{display:grid;grid-template-columns:1fr;gap:26px;align-items:start;padding-top:22px}
@media (min-width:900px){.home-grid{grid-template-columns:1fr 320px}}
.home-aside{display:flex;flex-direction:column;gap:16px}
@media (min-width:900px){.home-aside{position:sticky;top:84px}}
.home-week{margin-top:26px}
.home-week:empty{display:none}

/* ---------- hero (index.html) ---------- */
.hero{
  background:linear-gradient(150deg,#274a86,#16233f 78%);
  color:#fff;border-radius:var(--radius-xl);padding:38px 34px 34px;
  position:relative;overflow:hidden;
  box-shadow:var(--shadow-lg);
}
.hero::after{
  content:"";position:absolute;right:-80px;top:-90px;width:280px;height:280px;
  background:radial-gradient(circle,rgba(94,166,231,.35),transparent 70%);
  pointer-events:none;
}
.hero::before{
  content:"";position:absolute;left:-40px;bottom:-100px;width:220px;height:220px;
  background:radial-gradient(circle,rgba(238,157,51,.22),transparent 72%);
  pointer-events:none;
}
.hero .eyebrow{position:relative;font-size:.76rem;letter-spacing:.16em;text-transform:uppercase;opacity:.85;font-weight:800}
.hero-quote{
  position:relative;
  font-family:'Plus Jakarta Sans',system-ui,sans-serif;font-style:normal;font-weight:600;
  margin:0;font-size:1.55rem;line-height:1.42;max-width:56ch;letter-spacing:-.01em;
}

/* ---------- dashboard / sidebar cards ---------- */
.dash-card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius-md);
  padding:18px 20px;box-shadow:var(--shadow-sm)}
.dash-greet{display:flex;flex-direction:column;gap:10px}
.dash-greet .row1{display:flex;align-items:center;justify-content:space-between;gap:10px}
.dash-greet h3{font-family:'Plus Jakarta Sans',system-ui,sans-serif;margin:0;font-size:1.08rem}
.dash-switch{font-size:.83rem;font-weight:700;color:var(--brand)}
.streak-pill{background:#fff3e0;color:#a15c00;font-weight:800;border-radius:999px;padding:6px 13px;font-size:.85rem;white-space:nowrap;align-self:flex-start}
.dash-login-prompt{display:flex;flex-direction:column;gap:12px}
.dash-login-prompt p{margin:0;color:var(--muted);font-size:.92rem}
.dash-login-btn{display:inline-block;text-align:center;background:linear-gradient(150deg,var(--brand2),var(--brand));color:#fff;
  font-family:'Plus Jakarta Sans',system-ui,sans-serif;font-weight:700;border-radius:11px;padding:11px 18px}

.overview-card .ov-title{font-family:'Plus Jakarta Sans',system-ui,sans-serif;font-weight:800;font-size:.95rem;margin:0 0 12px;color:var(--ink)}
.overview-card .ov-row{display:flex;align-items:center;justify-content:space-between;font-size:.86rem;color:var(--muted);padding:8px 0;border-top:1px solid var(--line)}
.overview-card .ov-row:first-of-type{border-top:none;padding-top:0}
.overview-card .ov-row b{color:var(--ink);font-weight:800}
.overview-card .ov-total{margin-top:12px;padding-top:12px;border-top:1px solid var(--line);display:flex;align-items:baseline;justify-content:space-between}
.overview-card .ov-total .n{font-family:'Plus Jakarta Sans',system-ui,sans-serif;font-size:1.5rem;font-weight:800;color:var(--brand)}
.overview-card .ov-total .l{font-size:.8rem;color:var(--muted);font-weight:700}

/* ---------- section label ---------- */
.section-label{font-family:'Plus Jakarta Sans',system-ui,sans-serif;font-weight:800;font-size:1.15rem;margin:30px 2px 4px;color:var(--ink);letter-spacing:-.01em}

/* ---------- book / series grid ("bookshelf") ---------- */
.book-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:18px;margin-top:14px}

.book-card{
  --b-accent:var(--accent);--b-accent2:var(--accent2);
  position:relative;display:flex;flex-direction:column;
  background:var(--card);border-radius:var(--radius-lg);overflow:hidden;
  border:1px solid var(--line);color:var(--ink);
  box-shadow:var(--shadow-sm);
  transition:transform .2s ease, box-shadow .2s ease;
}
.book-card::before{ /* the "spine" */
  content:"";position:absolute;left:0;top:0;bottom:0;width:12px;
  background:linear-gradient(180deg,var(--b-accent2),var(--b-accent));
  transition:width .2s ease;
}
.book-card:hover{transform:translateY(-4px);box-shadow:var(--shadow-md)}
.book-card:hover::before{width:16px}

.book-cover-top{
  margin-left:12px;padding:22px 20px 18px;color:#fff;position:relative;
  background:linear-gradient(155deg,var(--b-accent2),var(--b-accent));
}
.book-cover-top .icon{
  font-size:1.9rem;display:inline-grid;place-items:center;width:50px;height:50px;
  background:rgba(255,255,255,.2);border-radius:14px;margin-bottom:10px;
}
.book-cover-top .series{font-family:'Plus Jakarta Sans',system-ui,sans-serif;font-weight:700;font-size:1.08rem;line-height:1.22;margin:0}
.book-cover-top .part{opacity:.9;font-weight:600;font-size:.9rem;margin:.15em 0 0}
.book-cover-top .audience-tag{
  position:absolute;top:18px;right:16px;font-size:.66rem;font-weight:800;letter-spacing:.04em;
  text-transform:uppercase;background:rgba(255,255,255,.22);padding:5px 9px;border-radius:999px;
  max-width:46%;text-align:right;line-height:1.25;
}

.book-cover-body{margin-left:12px;padding:16px 20px 20px;flex:1;display:flex;flex-direction:column;gap:11px}
.book-blurb{margin:0;color:var(--muted);font-size:.88rem}
.book-stats{color:var(--muted);font-size:.82rem;font-weight:700}

.part-pills{display:flex;flex-wrap:wrap;gap:6px}
.part-pill{
  --b-accent:inherit;font-size:.7rem;font-weight:800;padding:4px 10px;border-radius:999px;
  color:var(--b-accent);background:color-mix(in srgb, var(--b-accent) 10%, white);
  border:1px solid color-mix(in srgb, var(--b-accent) 26%, white);
}

.book-progress .plabel{display:flex;justify-content:space-between;font-size:.78rem;font-weight:700;color:var(--muted);margin-bottom:4px}
.pbar-track{height:7px;background:var(--paper);border:1px solid var(--line);border-radius:999px;overflow:hidden}
.pbar-fill{height:100%;border-radius:999px;background:linear-gradient(90deg,var(--b-accent2),var(--b-accent));transition:width .5s ease}

.book-cta{margin-top:auto;font-family:'Plus Jakarta Sans',system-ui,sans-serif;font-weight:700;font-size:.92rem;color:var(--b-accent);display:flex;align-items:center;gap:6px}
.book-card:hover .book-cta span{transform:translateX(3px)}
.book-cta span{display:inline-block;transition:transform .2s ease}

/* ---------- book / series page header ---------- */
.back-link{display:inline-flex;align-items:center;gap:6px;margin-bottom:16px;color:var(--accent);font-weight:700;font-size:.9rem}
.book-header{
  background:linear-gradient(155deg,var(--accent2),var(--accent));color:#fff;
  border-radius:var(--radius-xl);padding:30px 30px 26px;
  box-shadow:var(--shadow-lg);
}
.book-header .eyebrow{font-size:.74rem;letter-spacing:.14em;text-transform:uppercase;opacity:.88;font-weight:800}
.book-header h1{font-family:'Plus Jakarta Sans',system-ui,sans-serif;font-weight:800;margin:.2em 0 .1em;font-size:1.85rem;letter-spacing:-.01em}
.book-header p{margin:0;opacity:.92}
.book-header-bar{display:flex;align-items:center;justify-content:space-between;gap:14px;flex-wrap:wrap;margin-top:18px}
.results-link{font-weight:800;background:rgba(255,255,255,.16);color:#fff;border:1px solid rgba(255,255,255,.3);border-radius:11px;padding:9px 15px;font-family:'Plus Jakarta Sans',system-ui,sans-serif;font-size:.88rem}
.mini-progress{display:flex;align-items:center;gap:10px;font-size:.82rem;font-weight:800;min-width:170px}
.mini-progress .pbar-track{flex:1;background:rgba(255,255,255,.3);border:none}
.mini-progress .pbar-fill{background:#fff}

/* ---------- book page layout: sidebar (progress + section nav) + main grid ---------- */
.book-layout{display:grid;grid-template-columns:1fr;gap:22px;align-items:start;padding-top:20px}
@media (min-width:880px){.book-layout{grid-template-columns:250px 1fr}}
.book-side{display:flex;flex-direction:column;gap:14px}
@media (min-width:880px){.book-side{position:sticky;top:20px}}
.side-progress-card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius-md);padding:18px;box-shadow:var(--shadow-sm);text-align:center}
.side-progress-card .ring{--p:0;width:104px;height:104px;border-radius:50%;margin:0 auto 12px;display:grid;place-items:center;background:conic-gradient(var(--accent) calc(var(--p)*1%), var(--line) 0)}
.side-progress-card .ring .inner{width:82px;height:82px;border-radius:50%;background:var(--card);display:grid;place-items:center}
.side-progress-card .ring .pct{font-family:'Plus Jakarta Sans',system-ui,sans-serif;font-weight:800;font-size:1.25rem;color:var(--accent);line-height:1}
.side-progress-card .lbl{font-size:.82rem;color:var(--muted);font-weight:700;margin-top:2px}

/* section nav — vertical on desktop sidebar, horizontal pill bar on mobile */
.sectionnav{display:flex;gap:6px}
.sectionnav button{flex:1;border:1.5px solid var(--line);background:var(--card);font-family:'Plus Jakarta Sans',system-ui,sans-serif;font-weight:700;font-size:.86rem;
  padding:10px 12px;border-radius:11px;cursor:pointer;color:var(--muted);text-align:center}
.sectionnav button.active{background:linear-gradient(150deg,var(--accent2),var(--accent));color:#fff;border-color:var(--accent)}
@media (min-width:880px){
  .sectionnav{flex-direction:column;background:var(--card);border:1px solid var(--line);border-radius:var(--radius-md);padding:6px;box-shadow:var(--shadow-sm)}
  .sectionnav button{border:none;text-align:left;background:transparent}
  .sectionnav button.active{background:linear-gradient(150deg,var(--accent2),var(--accent))}
}
/* legacy alias kept for compatibility */
.tabbar{display:inline-flex;gap:4px;background:#eef1f6;padding:5px;border-radius:999px;margin:20px 0 6px}
.tabbtn{border:none;background:transparent;font-family:'Plus Jakarta Sans',system-ui,sans-serif;font-weight:700;font-size:.9rem;
  padding:9px 18px;border-radius:999px;cursor:pointer;color:var(--muted)}
.tabbtn.active{background:linear-gradient(150deg,var(--accent2),var(--accent));color:#fff}

/* ---------- unit list ---------- */
.unit-grid{display:grid;gap:12px;margin-top:0}
.unit-card{
  position:relative;display:flex;align-items:center;gap:16px;background:var(--card);
  border:1px solid var(--line);border-radius:16px;padding:15px 18px;
  box-shadow:var(--shadow-sm);transition:transform .15s ease, border-color .15s ease, box-shadow .15s ease;color:var(--ink);
}
.unit-card:hover{transform:translateY(-2px);border-color:var(--accent2);box-shadow:var(--shadow-md)}
.unit-card.done{border-color:var(--correct)}
.unit-badge{
  width:48px;height:48px;border-radius:13px;flex:none;display:grid;place-items:center;
  font-family:'Plus Jakarta Sans',system-ui,sans-serif;font-weight:700;font-size:1rem;color:#fff;
  background:linear-gradient(150deg,var(--accent2),var(--accent));
}
.unit-card .info{flex:1;min-width:0}
.unit-card .t{font-weight:700;font-size:1rem}
.unit-card .s{color:var(--muted);font-size:.86rem;margin-top:1px}
.unit-card .go{font-family:'Plus Jakarta Sans',system-ui,sans-serif;font-weight:700;font-size:.9rem;color:var(--accent);white-space:nowrap}
.unit-card .check{
  position:absolute;top:-8px;right:-8px;background:var(--correct);color:#fff;border-radius:999px;
  width:24px;height:24px;display:grid;place-items:center;font-size:.8rem;font-weight:800;
  box-shadow:0 3px 8px -2px rgba(0,0,0,.3);
}

/* ---------- misc ---------- */
.empty-state{background:var(--card);border:1px solid var(--line);border-radius:var(--radius-md);
  padding:34px 22px;text-align:center;color:var(--muted);font-weight:700;margin-top:20px}
.empty-state p{margin:0 0 14px}
footer.site-footer{text-align:center;color:var(--muted);font-size:.85rem;margin-top:36px}

@media(max-width:520px){
  .wrap{padding:0 16px 56px}
  .hero{padding:26px 22px 24px}
  .hero-quote{font-size:1.2rem}
  .book-header{padding:22px 20px 20px}
  .book-header h1{font-size:1.5rem}
}

/* "See my per-quiz scores" link at the foot of the progress overview card. */
.overview-card .ov-link{display:block;margin-top:12px;padding-top:11px;border-top:1px solid var(--line);font-weight:800;font-size:.86rem;color:var(--brand);text-decoration:none}
.overview-card .ov-link:hover{text-decoration:underline}

/* "N words due today" card on the home dashboard, above the progress overview. */
.review-card{display:block;text-decoration:none;background:linear-gradient(150deg,var(--brand2,#5bb3e4),var(--brand,#1c6ea4) 88%);color:#fff;border:0}
.review-card .rc-title{font-family:'Plus Jakarta Sans',system-ui,sans-serif;font-weight:800;font-size:.95rem;margin:0 0 6px}
.review-card .rc-count{margin:0;font-size:.92rem;opacity:.95}
.review-card .rc-count b{font-family:'Plus Jakarta Sans',system-ui,sans-serif;font-size:1.6rem;font-weight:800;display:block;line-height:1.1}
.review-card .rc-cta{display:inline-block;margin-top:10px;font-weight:800;font-size:.86rem;background:rgba(255,255,255,.18);border-radius:10px;padding:7px 13px}

/* Weekly activity strip on the home dashboard: what got done each day, laid
   out left-to-right (Mon..Sun) rather than as a tall table, grouped by unit
   so it reads as "which book/unit" rather than just an exercise-type chip. */
.week-card{width:100%}
.week-card .wk-title{font-family:'Plus Jakarta Sans',system-ui,sans-serif;font-weight:800;font-size:.95rem;margin:0 0 12px;color:var(--ink);display:flex;align-items:baseline;gap:8px}
.week-card .wk-sum{margin-left:auto;font-size:.8rem;font-weight:700;color:var(--muted)}
.wk-strip{display:flex;gap:10px;overflow-x:auto;padding-bottom:2px}
.wk-daycol{flex:1 0 148px;min-width:148px;background:var(--paper);border-radius:14px;padding:10px 10px 12px;display:flex;flex-direction:column;gap:8px}
.wk-daycol.wk-today{background:color-mix(in srgb, var(--brand2) 14%, transparent)}
.wk-dayhead{display:flex;flex-direction:column;gap:1px;padding-bottom:7px;border-bottom:1px solid var(--line)}
.wk-day{font-size:.82rem;font-weight:700;color:var(--ink)}
.wk-daycol.wk-today .wk-day{color:var(--brand);font-weight:800}
.wk-date{font-size:.72rem;color:var(--muted);font-weight:700}
.wk-daybody{display:flex;flex-direction:column;gap:7px}
.wk-none{font-size:.78rem;color:var(--muted)}
.wk-unit{display:block;background:var(--card);border:1px solid var(--line);border-radius:10px;padding:7px 8px}
.wk-unit:hover{border-color:var(--brand2)}
.wk-unit-title{font-size:.78rem;font-weight:700;color:var(--ink);line-height:1.28;
  display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.wk-unit-book{font-size:.7rem;color:var(--muted);font-weight:700;margin-top:3px}
.wk-parts{display:flex;flex-wrap:wrap;gap:4px;margin-top:6px}
.wk-part{background:color-mix(in srgb, var(--brand2) 16%, transparent);border-radius:999px;
  width:20px;height:20px;display:inline-flex;align-items:center;justify-content:center;font-size:.74rem}

/* The top bar carries four links since "Ôn lại từ" was added; let them wrap
   and tighten the spacing on narrow phones rather than overflow the page. */
@media (max-width:560px){
  /* The bar is a body-level element, so the desktop negative margin has no
     container padding to cancel out here and just pushes it past the edge. */
  .site-topbar{flex-wrap:wrap;gap:6px 8px;padding:12px 16px;margin-bottom:18px}
  .site-topbar .brand{flex:1 0 100%}
  .site-topbar-spacer{display:none}
  .site-topbar .tb-link{font-size:.8rem;padding:6px 9px}
}