/* ======================================================
   CODEBOOKUSA — Full Prototype Styles
   Flag palette: Navy #002868, Red #BF0A30, White #FFF
   ====================================================== */

*,*::before,*::after{margin:0;padding:0;box-sizing:border-box}

:root{
  --navy:#002868;
  --red:#BF0A30;
  --white:#ffffff;
  --bg:#f5f5f4;
  --card:#fff;
  --text:#1c1917;
  --muted:#78716c;
  --border:#e7e5e4;
  --radius:10px;
  --tap:48px;
}

[data-theme="dark"]{
  --navy:#4a90d9;
  --red:#e05060;
  --bg:#121212;
  --card:#1e1e1e;
  --text:#e0e0e0;
  --muted:#9e9e9e;
  --border:#333;
  --white:#1e1e1e;
}
[data-theme="dark"] .store-header{
  background:#1a1a2e;
}
[data-theme="dark"] .logo span:first-child{
  color:#4a90d9;
}
[data-theme="dark"] .btn-primary{
  background:var(--navy);color:#fff;
}
[data-theme="dark"] .detail-view,
[data-theme="dark"] .reader-view{
  background:var(--bg);
}
[data-theme="dark"] .reader-header{
  background:var(--card);border-color:var(--border);
}
[data-theme="dark"] .reader-footer{
  background:var(--card);border-color:var(--border);
}
[data-theme="dark"] .code-section{
  background:#1a1a2e;border-left-color:var(--navy);
}
[data-theme="dark"] .exception{
  background:#2a1a1a;border-left-color:var(--red);
}
[data-theme="dark"] .informational-note{
  background:#1a2a1a;
}
[data-theme="dark"] .book-card{
  background:var(--card);
}
[data-theme="dark"] .filter{
  background:var(--card);color:var(--text);border-color:var(--border);
}
[data-theme="dark"] .filter.active{
  background:var(--navy);color:#fff;
}
[data-theme="dark"] .tab{
  color:var(--muted);
}
[data-theme="dark"] .tab.active{
  color:var(--navy);border-color:var(--navy);
}
[data-theme="dark"] .cart-drawer,
[data-theme="dark"] .account-panel,
[data-theme="dark"] .notes-panel{
  background:var(--card);
}
[data-theme="dark"] .detail-add-btn{
  background:var(--navy);
}
[data-theme="dark"] .detail-add-btn.in-cart{
  background:#2d7d3a;
}
[data-theme="dark"] .quiz-option{
  background:var(--card);border-color:var(--border);color:var(--text);
}
[data-theme="dark"] .flashcard-front,
[data-theme="dark"] .flashcard-back{
  background:var(--card);border-color:var(--border);color:var(--text);
}
[data-theme="dark"] .study-mode-card{
  background:var(--card);border-color:var(--border);
}
[data-theme="dark"] .shop-card{
  background:var(--card);border-color:var(--border);
}
[data-theme="dark"] .detail-preview-btn{
  background:var(--card);color:var(--text);border-color:var(--border);
}
[data-theme="dark"] .search-wrap input{
  background:var(--card);color:var(--text);border-color:var(--border);
}
[data-theme="dark"] .preview-lock{
  background:linear-gradient(to bottom, transparent 0%, var(--bg) 60%);
}
[data-theme="dark"] .note-popup{
  background:var(--card);border-color:var(--border);
}
[data-theme="dark"] .note-popup textarea{
  background:var(--bg);color:var(--text);border-color:var(--border);
}
/* Reader content */
[data-theme="dark"] .reader-body .code-section p,
[data-theme="dark"] .reader-body .code-section{
  color:var(--text);
}
[data-theme="dark"] .reader-body .exception{
  background:#2a2215;border-left-color:#b45309;color:#fbbf24;
}
[data-theme="dark"] .reader-body .exception strong{color:#fbbf24}
[data-theme="dark"] .reader-body .informational-note{
  background:#1a2233;color:#93c5fd;border-left-color:#3b82f6;
}
[data-theme="dark"] .reader-body th{
  background:var(--border);color:var(--text);
}
[data-theme="dark"] .reader-body td{
  border-color:var(--border);color:var(--text);
}
/* Detail page */
[data-theme="dark"] .detail-header{
  background:var(--card);border-color:var(--border);
}
[data-theme="dark"] .detail-price{
  color:var(--text);
}
[data-theme="dark"] .detail-section h3{
  color:var(--text);
}
/* Owned badge */
[data-theme="dark"] .owned-badge{
  color:#4ade80;
}
/* Quiz correct/wrong */
[data-theme="dark"] .quiz-option.correct{
  border-color:#22c55e;background:#0a2a12;color:#4ade80;
}
[data-theme="dark"] .quiz-option.wrong{
  border-color:#ef4444;background:#2a0a0a;color:#f87171;
}
[data-theme="dark"] .quiz-explanation{
  background:#1a2233;color:#93c5fd;
}
/* Flashcard */
[data-theme="dark"] .flashcard-def{
  color:var(--muted);
}
[data-theme="dark"] .flashcard-ref{
  color:var(--muted);
}
/* Note card annotation */
[data-theme="dark"] .note-card-annotation{
  color:var(--muted);
}
/* Highlight toolbar */
[data-theme="dark"] .hl-toolbar{
  background:var(--card);border-color:var(--border);
}
/* Auth pages */
[data-theme="dark"] .auth-page{
  background:var(--bg);
}
[data-theme="dark"] .auth-card{
  background:var(--card);border-color:var(--border);
}
[data-theme="dark"] .auth-input{
  background:var(--bg);color:var(--text);border-color:var(--border);
}
[data-theme="dark"] .social-btn{
  background:var(--card);color:var(--text);border-color:var(--border);
}

html{font-size:16px;-webkit-text-size-adjust:100%}
body{
  font-family:'Inter',system-ui,sans-serif;
  background:var(--bg);
  color:var(--text);
  -webkit-font-smoothing:antialiased;
  overflow-x:hidden;
}
a{color:var(--navy);font-weight:600}
button{font-family:inherit;cursor:pointer}
.hidden{display:none !important}

/* ---- Views ---- */
.view{min-height:100dvh}

/* ---- Buttons ---- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;
  height:52px;padding:0 28px;
  border:none;border-radius:var(--radius);
  font-size:16px;font-weight:700;
  transition:all .15s;
  -webkit-tap-highlight-color:transparent;
}
.btn-primary{background:var(--navy);color:var(--white)}
.btn-primary:active{background:#001a4a}
.btn-outline{background:transparent;color:var(--navy);border:2px solid var(--navy)}
.btn-outline:active{background:rgba(0,40,104,.06)}
.btn-full{width:100%}
.btn-red{background:var(--red);color:var(--white)}
.btn-red:active{background:#9a0826}

/* ======================================================
   HOME PAGE
   ====================================================== */
.home{
  min-height:100dvh;
  display:flex;flex-direction:column;
  align-items:center;justify-content:center;
  position:relative;
  overflow:hidden;
  background:var(--white);
}

/* Decorative flag stripes */
.flag-stripe{
  position:absolute;left:0;right:0;height:18px;
  opacity:.12;
}
.stripe-r{background:var(--red);top:0}
.stripe-w{background:transparent;top:18px}
.stripe-r2{background:var(--red);bottom:0}

.home-content{
  width:100%;max-width:360px;
  padding:40px 24px;
  text-align:center;
  position:relative;z-index:1;
}

/* Flag badge / logo */
.home-logo{margin-bottom:48px}

.flag-badge{
  width:80px;height:56px;
  background:var(--navy);
  border-radius:6px;
  display:flex;align-items:center;justify-content:center;
  margin:0 auto 20px;
  position:relative;
  box-shadow:0 4px 16px rgba(0,40,104,.25);
}
.stars-field{
  display:flex;flex-direction:column;
  align-items:center;gap:1px;
  color:var(--white);
  font-size:9px;
  letter-spacing:3px;
  line-height:1.3;
}

.home-brand{
  font-size:36px;font-weight:900;
  letter-spacing:-1px;
  line-height:1;
  margin-bottom:8px;
}
.brand-code{color:var(--navy)}
.brand-book{color:var(--text)}
.brand-usa{
  color:var(--red);
  position:relative;
}

.home-tagline{
  font-size:14px;color:var(--muted);font-weight:500;
}

.home-actions{
  display:flex;flex-direction:column;gap:12px;
  margin-bottom:24px;
}

.home-guest{
  font-size:14px;color:var(--muted);
}
.home-guest a{color:var(--muted);text-decoration:underline;font-weight:500}

/* ======================================================
   AUTH PAGES
   ====================================================== */
.auth-page{
  min-height:100dvh;
  background:var(--white);
  padding:16px 20px;
}
.back-link{
  background:none;border:none;
  font-size:15px;font-weight:600;color:var(--navy);
  min-height:var(--tap);display:flex;align-items:center;
}
.auth-box{
  max-width:380px;margin:20px auto 0;
}
.auth-title{
  font-size:26px;font-weight:900;
  margin-bottom:28px;
}
.field-label{
  display:block;
  font-size:13px;font-weight:600;color:var(--muted);
  text-transform:uppercase;letter-spacing:.5px;
  margin-bottom:6px;margin-top:18px;
}
.field-label:first-of-type{margin-top:0}
.optional{font-weight:400;text-transform:none;letter-spacing:0}
.field{
  width:100%;height:50px;
  border:1.5px solid var(--border);border-radius:8px;
  padding:0 14px;
  font-size:16px;font-family:inherit;color:var(--text);
  background:var(--bg);
  -webkit-appearance:none;
}
.field:focus{outline:none;border-color:var(--navy)}
select.field{color:var(--muted)}
select.field:valid{color:var(--text)}
/* Social login buttons */
.social-btns{display:flex;flex-direction:column;gap:10px;margin-bottom:4px}

.btn-social{
  display:flex;align-items:center;justify-content:center;gap:12px;
  width:100%;height:52px;
  border-radius:var(--radius);
  font-size:15px;font-weight:600;
  transition:all .15s;
  -webkit-tap-highlight-color:transparent;
  border:none;cursor:pointer;
}
.social-icon{flex-shrink:0}

.btn-google{
  background:#fff;color:#1c1917;
  border:1.5px solid var(--border) !important;
}
.btn-google:active{background:#f5f5f4}

.btn-apple{
  background:#000;color:#fff;
}
.btn-apple:active{background:#333}

.btn-email{
  background:#fff;color:#1c1917;
  border:1.5px solid var(--border) !important;
}
.btn-email:active{background:#f5f5f4}

/* Dividers */
.home-divider,.auth-divider{
  display:flex;align-items:center;gap:14px;
  margin:20px 0;
  color:var(--muted);font-size:13px;font-weight:500;
}
.home-divider::before,.home-divider::after,
.auth-divider::before,.auth-divider::after{
  content:'';flex:1;height:1px;background:var(--border);
}

.auth-box .btn-primary{margin-top:28px}
.auth-switch{
  text-align:center;margin-top:20px;
  font-size:14px;color:var(--muted);
}

/* ======================================================
   STORE HEADER
   ====================================================== */
.header{
  position:sticky;top:0;z-index:50;
  background:var(--white);
  border-bottom:1px solid var(--border);
  padding:10px 16px 0;
}
.header-bar{
  display:flex;align-items:center;justify-content:space-between;
  margin-bottom:10px;
}

.brand-sm{font-size:18px;font-weight:900;letter-spacing:-.5px}
.brand-usa-sm{color:var(--red)}

.header-right{display:flex;align-items:center;gap:6px}

.icon-btn{
  position:relative;
  background:none;border:none;
  min-width:var(--tap);min-height:var(--tap);
  display:flex;align-items:center;justify-content:center;
  color:var(--text);-webkit-tap-highlight-color:transparent;
  border-radius:50%;
}
.icon-btn:active{background:var(--bg)}

.cart-count{
  position:absolute;top:4px;right:2px;
  background:var(--red);color:var(--white);
  font-size:11px;font-weight:700;
  width:18px;height:18px;border-radius:50%;
  display:flex;align-items:center;justify-content:center;
}

/* Theme Toggle */
.theme-toggle{
  width:36px;height:36px;border-radius:50%;
  background:transparent;border:1.5px solid var(--border);
  color:var(--text);display:flex;align-items:center;justify-content:center;
  cursor:pointer;transition:background .2s,color .2s;
}
.theme-toggle:hover{background:var(--border)}
.theme-icon-dark{display:none}
[data-theme="dark"] .theme-icon-light{display:none}
[data-theme="dark"] .theme-icon-dark{display:block}
[data-theme="dark"] .theme-toggle{
  border-color:var(--border);color:var(--text);
}

.avatar-btn{
  width:36px;height:36px;border-radius:50%;
  background:var(--navy);border:none;
  color:#fff;font-size:14px;font-weight:700;
  display:flex;align-items:center;justify-content:center;
  cursor:pointer;
}

/* Search */
.search-wrap{position:relative;margin-bottom:10px}
.search-ico{position:absolute;left:12px;top:50%;transform:translateY(-50%);pointer-events:none}
.search{
  width:100%;height:42px;
  border:1.5px solid var(--border);border-radius:8px;
  padding:0 12px 0 40px;
  font-size:15px;color:var(--text);background:var(--bg);
  -webkit-appearance:none;
}
.search:focus{outline:none;border-color:var(--navy)}

/* Tabs */
.tabs{
  display:flex;gap:0;
  border-bottom:none;
}
.tab{
  flex:1;
  height:42px;
  background:none;border:none;
  font-size:14px;font-weight:600;color:var(--muted);
  border-bottom:2.5px solid transparent;
  transition:all .15s;
}
.tab.active{
  color:var(--navy);
  border-bottom-color:var(--navy);
}

/* Filters */
.filters{
  display:flex;gap:6px;
  padding:12px 16px;
  overflow-x:auto;
  -webkit-overflow-scrolling:touch;
  scrollbar-width:none;
  background:var(--white);
  border-bottom:1px solid var(--border);
}
.filters::-webkit-scrollbar{display:none}
.filter{
  flex-shrink:0;
  height:34px;padding:0 16px;
  border:1.5px solid var(--border);border-radius:17px;
  background:var(--white);
  font-size:13px;font-weight:600;color:var(--muted);
  white-space:nowrap;transition:all .15s;
}
.filter.active{
  background:var(--navy);color:var(--white);border-color:var(--navy);
}

/* ======================================================
   BOOK GRID
   ====================================================== */
.book-grid{
  display:grid;
  grid-template-columns:repeat(2,1fr);
  gap:14px;
  padding:14px 16px 40px;
}

.book-card{
  background:var(--card);
  border-radius:var(--radius);
  overflow:hidden;
  box-shadow:0 1px 3px rgba(0,0,0,.05);
  cursor:pointer;
  transition:transform .15s;
  -webkit-tap-highlight-color:transparent;
}
.book-card:active{transform:scale(.97)}

.book-cover{
  width:100%;aspect-ratio:3/4;
  overflow:hidden;
}

/* CSS book covers */
.cover-art{
  width:100%;height:100%;
  display:flex;flex-direction:column;
  align-items:center;justify-content:center;
  padding:14px 10px;
  text-align:center;
  color:#fff;position:relative;
}
.cover-stripe{
  position:absolute;top:0;left:0;right:0;height:5px;
  background:var(--red);opacity:.7;
}
.cover-publisher{
  font-size:9px;font-weight:700;
  text-transform:uppercase;letter-spacing:2px;
  opacity:.75;margin-bottom:auto;padding-top:8px;
}
.cover-title{
  font-size:16px;font-weight:800;line-height:1.2;
  margin-bottom:4px;
  text-shadow:0 1px 4px rgba(0,0,0,.25);
}
.cover-year{
  font-size:30px;font-weight:900;
  margin-bottom:auto;
  text-shadow:0 2px 6px rgba(0,0,0,.2);
}
.cover-bottom-label{
  font-size:8px;font-weight:600;
  text-transform:uppercase;letter-spacing:1.5px;
  opacity:.6;padding-bottom:8px;
}

.book-info{padding:10px 12px 14px}
.book-title{
  font-size:13px;font-weight:700;line-height:1.3;
  margin-bottom:2px;
  display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden;
}
.book-edition{font-size:11px;color:var(--muted);font-weight:500;margin-bottom:6px}
.book-price{font-size:16px;font-weight:800}

/* Owned badge */
.owned-badge{
  display:inline-flex;align-items:center;gap:4px;
  font-size:11px;font-weight:700;color:#16a34a;
  margin-top:4px;
}

/* Card preview button */
.card-preview-btn{
  display:inline-block;
  margin-top:6px;
  padding:4px 12px;
  font-size:11px;font-weight:700;
  color:var(--navy);
  background:transparent;
  border:1.5px solid var(--navy);
  border-radius:6px;
  cursor:pointer;
  transition:background .15s, color .15s;
}
.card-preview-btn:hover{
  background:var(--navy);color:#fff;
}
[data-theme="dark"] .card-preview-btn{
  border-color:var(--navy);color:var(--navy);
}
[data-theme="dark"] .card-preview-btn:hover{
  background:var(--navy);color:#fff;
}

/* Empty library */
.empty-state{
  grid-column:1/-1;
  text-align:center;padding:80px 24px;
  color:var(--muted);
}
.empty-state h3{font-size:18px;color:var(--text);margin-bottom:8px}
.empty-state p{font-size:14px;line-height:1.6}

/* ======================================================
   DETAIL VIEW
   ====================================================== */
.detail-view{
  position:fixed;inset:0;
  background:var(--bg);
  z-index:60;
  transform:translateX(100%);
  transition:transform .25s ease;
  overflow-y:auto;
  -webkit-overflow-scrolling:touch;
}
.detail-view.open{transform:translateX(0)}

.detail-header{
  position:sticky;top:0;z-index:2;
  background:var(--white);
  border-bottom:1px solid var(--border);
  padding:8px 12px;
}
.back-btn{
  display:flex;align-items:center;gap:6px;
  background:none;border:none;
  font-size:15px;font-weight:600;color:var(--text);
  min-height:var(--tap);padding:0 4px;
}

.detail-body{padding-bottom:40px}

.detail-cover-wrap{
  display:flex;justify-content:center;
  padding:24px 16px 0;background:var(--white);
}
.detail-cover{
  width:180px;aspect-ratio:3/4;
  border-radius:6px;overflow:hidden;
  box-shadow:0 8px 30px rgba(0,0,0,.2);
}
.detail-cover .cover-title{font-size:20px}
.detail-cover .cover-year{font-size:36px}

.detail-meta{
  background:var(--white);
  padding:20px 20px 24px;text-align:center;
}
.detail-title{font-size:20px;font-weight:800;line-height:1.25;margin-bottom:4px}
.detail-subtitle{font-size:14px;color:var(--muted);margin-bottom:16px}
.detail-price{font-size:28px;font-weight:900;margin-bottom:16px}

.detail-add-btn{
  width:100%;max-width:360px;height:54px;
  border:none;border-radius:var(--radius);
  background:var(--navy);color:var(--white);
  font-size:17px;font-weight:700;
  transition:background .15s;
}
.detail-add-btn:active{background:#001a4a}
.detail-add-btn.in-cart{background:#16a34a}
.detail-add-btn.owned{background:var(--muted);cursor:default}

.detail-section{padding:20px}
.detail-section h3{font-size:15px;font-weight:700;margin-bottom:10px}
.detail-section p{font-size:14px;line-height:1.65;color:var(--muted)}

.detail-specs{padding:0 20px 20px}
.spec-row{
  display:flex;justify-content:space-between;
  padding:12px 0;border-bottom:1px solid var(--border);
  font-size:14px;
}
.spec-label{color:var(--muted);font-weight:500}
.spec-value{font-weight:600;text-align:right}

/* ======================================================
   PANELS (cart + account)
   ====================================================== */
.overlay{
  position:fixed;inset:0;
  background:rgba(0,0,0,.35);
  z-index:100;
  opacity:0;visibility:hidden;
  transition:all .2s;
}
.overlay.open{opacity:1;visibility:visible}

.cart-drawer,.account-panel{
  position:fixed;top:0;right:0;
  width:90%;max-width:380px;height:100%;
  background:var(--white);
  z-index:101;
  transform:translateX(100%);
  transition:transform .25s ease;
  display:flex;flex-direction:column;
}
.cart-drawer.open,.account-panel.open{transform:translateX(0)}

.panel-top{
  display:flex;align-items:center;justify-content:space-between;
  padding:16px 20px;border-bottom:1px solid var(--border);
}
.panel-top h2{font-size:18px;font-weight:800}
.close-x{
  background:none;border:none;
  font-size:22px;color:var(--muted);
  min-width:var(--tap);min-height:var(--tap);
  display:flex;align-items:center;justify-content:center;
}

/* Cart */
.cart-list{flex:1;overflow-y:auto;padding:12px 20px}
.cart-empty{text-align:center;padding:60px 0;color:var(--muted);font-size:15px}
.cart-item{
  display:flex;align-items:center;gap:12px;
  padding:14px 0;border-bottom:1px solid var(--border);
}
.cart-item-thumb{
  width:44px;aspect-ratio:3/4;border-radius:4px;overflow:hidden;flex-shrink:0;
}
.cart-item-thumb .cover-art{padding:4px}
.cart-item-thumb .cover-title{font-size:5px}
.cart-item-thumb .cover-year{font-size:9px}
.cart-item-thumb .cover-publisher,.cart-item-thumb .cover-bottom-label,.cart-item-thumb .cover-stripe{display:none}
.cart-item-info{flex:1;min-width:0}
.cart-item-name{font-size:14px;font-weight:700;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.cart-item-price{font-size:13px;color:var(--muted);font-weight:500}
.cart-item-rm{
  background:none;border:none;
  color:var(--red);font-size:13px;font-weight:600;
  min-width:var(--tap);min-height:var(--tap);
  display:flex;align-items:center;justify-content:center;
  font-family:inherit;
}

.cart-bottom{
  padding:16px 20px;border-top:1px solid var(--border);
  background:var(--bg);
}
.cart-total-row{
  display:flex;justify-content:space-between;
  font-size:18px;font-weight:800;margin-bottom:14px;
}

/* Account panel */
.account-info{padding:24px 20px;flex:1;overflow-y:auto}
.account-card{
  background:var(--bg);border-radius:var(--radius);
  padding:20px;margin-bottom:16px;
}
.account-name{font-size:20px;font-weight:800;margin-bottom:2px}
.account-email{font-size:14px;color:var(--muted)}
.account-trade{
  display:inline-block;margin-top:10px;
  font-size:12px;font-weight:600;
  background:var(--navy);color:var(--white);
  padding:4px 12px;border-radius:12px;
}
.account-stat{
  display:flex;justify-content:space-between;align-items:center;
  padding:14px 0;border-bottom:1px solid var(--border);
  font-size:15px;
}
.account-stat-label{color:var(--muted);font-weight:500}
.account-stat-val{font-weight:700}
.sign-out-btn{
  width:100%;height:48px;margin-top:24px;
  border:1.5px solid var(--red);border-radius:var(--radius);
  background:transparent;color:var(--red);
  font-size:15px;font-weight:600;
}

/* ======================================================
   BOOK COVER IMAGES
   ====================================================== */
.cover-img{
  width:100%;height:100%;object-fit:cover;
  display:block;
}

/* ======================================================
   READER VIEW
   ====================================================== */
.reader-view{
  position:fixed;inset:0;
  background:#fff;
  z-index:70;
  transform:translateX(100%);
  transition:transform .25s ease;
  display:flex;flex-direction:column;
}
.reader-view.open{transform:translateX(0)}

.reader-header{
  display:flex;align-items:center;
  padding:8px 12px;
  border-bottom:1px solid var(--border);
  background:var(--white);
  gap:8px;
  min-height:52px;
}
.reader-title{
  flex:1;font-size:14px;font-weight:700;
  white-space:nowrap;overflow:hidden;text-overflow:ellipsis;
  text-align:center;
}
.reader-search-btn{color:var(--muted)}

.reader-search-bar{
  padding:8px 16px;border-bottom:1px solid var(--border);
  background:var(--bg);
}
.reader-search-bar .field{height:40px;font-size:14px}

.reader-body{
  flex:1;overflow-y:auto;
  padding:20px 18px;
  -webkit-overflow-scrolling:touch;
  font-size:15px;line-height:1.75;color:var(--text);
}

.reader-body h2{
  font-size:18px;font-weight:800;
  color:var(--navy);margin:28px 0 12px;
  padding-bottom:6px;
  border-bottom:2px solid var(--navy);
}
.reader-body h2:first-child{margin-top:0}

.reader-body h3{
  font-size:15px;font-weight:700;
  color:var(--text);margin:20px 0 8px;
}

.reader-body p{margin-bottom:12px}

.reader-body .article-num{
  font-weight:800;color:var(--navy);
}

.reader-body .code-section{
  background:var(--bg);border-radius:8px;
  padding:14px 16px;margin:12px 0;
  border-left:3px solid var(--navy);
}

.reader-body .code-section .section-id{
  font-size:13px;font-weight:700;color:var(--navy);
  margin-bottom:4px;display:block;
}

.reader-body .exception{
  background:#fef3c7;border-radius:6px;
  padding:10px 14px;margin:8px 0;
  font-size:13px;border-left:3px solid #f59e0b;
}

.reader-body .exception strong{color:#92400e}

.reader-body .informational-note{
  background:#eff6ff;border-radius:6px;
  padding:10px 14px;margin:8px 0;
  font-size:13px;font-style:italic;
  border-left:3px solid var(--navy);
  color:#1e40af;
}

.reader-body .table-wrap{
  overflow-x:auto;margin:12px 0;
}
.reader-body table{
  width:100%;border-collapse:collapse;
  font-size:13px;
}
.reader-body th{
  background:var(--navy);color:#fff;
  padding:8px 10px;text-align:left;
  font-weight:600;font-size:12px;
}
.reader-body td{
  padding:8px 10px;border-bottom:1px solid var(--border);
}
.reader-body tr:nth-child(even) td{background:var(--bg)}

.reader-nav{
  display:flex;align-items:center;justify-content:space-between;
  padding:10px 16px;
  border-top:1px solid var(--border);
  background:var(--white);
}
.reader-nav-btn{
  background:none;border:none;
  font-size:14px;font-weight:600;color:var(--navy);
  min-height:var(--tap);min-width:80px;
  display:flex;align-items:center;justify-content:center;
  cursor:pointer;
}
.reader-nav-btn:disabled{color:var(--border);cursor:default}
.reader-page{
  font-size:13px;color:var(--muted);font-weight:500;
}

/* TOC */
.reader-toc{
  padding:12px 16px;background:var(--bg);
  border-bottom:1px solid var(--border);
  max-height:40vh;overflow-y:auto;
}
.toc-item{
  display:block;padding:10px 8px;
  font-size:14px;font-weight:600;color:var(--navy);
  border-bottom:1px solid var(--border);
  cursor:pointer;background:none;border-left:none;border-right:none;border-top:none;
  width:100%;text-align:left;
  font-family:inherit;
}
.toc-item:active{background:#eff6ff}

/* Reader tools row */
.reader-tools{display:flex;align-items:center;gap:2px}

/* Highlight search matches */
.reader-body mark{
  background:#fef08a;padding:1px 2px;border-radius:2px;
}

/* User highlights */
.reader-body .hl-yellow{background:#fef08a;padding:1px 2px;border-radius:2px;cursor:pointer}
.reader-body .hl-green{background:#bbf7d0;padding:1px 2px;border-radius:2px;cursor:pointer}
.reader-body .hl-blue{background:#bfdbfe;padding:1px 2px;border-radius:2px;cursor:pointer}
.reader-body .hl-pink{background:#fecdd3;padding:1px 2px;border-radius:2px;cursor:pointer}

.reader-body .hl-has-note{
  border-bottom:2px dashed #f59e0b;
}

/* Highlight toolbar */
.hl-toolbar{
  position:fixed;
  z-index:80;
  background:#fff;
  border:1px solid var(--border);
  border-radius:12px;
  box-shadow:0 4px 20px rgba(0,0,0,.15);
  padding:8px 10px;
  display:flex;align-items:center;gap:6px;
  left:50%;transform:translateX(-50%);
  bottom:70px;
}
.hl-toolbar.hidden{display:none}

.hl-color{
  width:32px;height:32px;
  border:2px solid transparent;
  border-radius:50%;
  cursor:pointer;
  transition:all .15s;
}
.hl-color:active{transform:scale(.9)}

.hl-divider{
  width:1px;height:24px;
  background:var(--border);
  margin:0 4px;
}

.hl-action{
  width:36px;height:36px;
  background:none;border:none;
  font-size:18px;
  display:flex;align-items:center;justify-content:center;
  cursor:pointer;border-radius:8px;
}
.hl-action:active{background:var(--bg)}

/* Note popup */
.note-popup{
  position:fixed;
  bottom:130px;left:50%;transform:translateX(-50%);
  width:calc(100% - 40px);max-width:340px;
  background:#fff;
  border:1px solid var(--border);
  border-radius:12px;
  box-shadow:0 8px 30px rgba(0,0,0,.18);
  padding:16px;
  z-index:81;
}
.note-popup textarea{
  width:100%;height:80px;
  border:1.5px solid var(--border);border-radius:8px;
  padding:10px 12px;
  font-size:14px;font-family:inherit;color:var(--text);
  resize:none;background:var(--bg);
}
.note-popup textarea:focus{outline:none;border-color:var(--navy)}
.note-popup-btns{
  display:flex;gap:8px;justify-content:flex-end;
  margin-top:10px;
}
.note-popup-btns button{
  height:38px;padding:0 20px;
  border:none;border-radius:8px;
  font-size:14px;font-weight:600;
  cursor:pointer;font-family:inherit;
}
.note-cancel{background:var(--bg);color:var(--muted)}
.note-save{background:var(--navy);color:#fff}

/* Notes panel */
.notes-panel{
  position:fixed;top:0;right:0;
  width:90%;max-width:380px;height:100%;
  background:var(--white);
  z-index:101;
  transform:translateX(100%);
  transition:transform .25s ease;
  display:flex;flex-direction:column;
}
.notes-panel.open{transform:translateX(0)}

.notes-tabs{
  display:flex;border-bottom:1px solid var(--border);
}
.notes-tab{
  flex:1;height:42px;
  background:none;border:none;
  font-size:13px;font-weight:600;color:var(--muted);
  border-bottom:2.5px solid transparent;
  cursor:pointer;font-family:inherit;
}
.notes-tab.active{color:var(--navy);border-bottom-color:var(--navy)}

.notes-list{
  flex:1;overflow-y:auto;padding:12px 16px;
}
.notes-empty{
  text-align:center;padding:60px 16px;
  color:var(--muted);font-size:14px;
}

.note-card{
  background:var(--bg);border-radius:var(--radius);
  padding:14px 16px;margin-bottom:10px;
  border-left:4px solid;
  cursor:pointer;
  transition:background .15s;
}
.note-card:active{background:#e7e5e4}
.note-card.color-yellow{border-left-color:#eab308}
.note-card.color-green{border-left-color:#22c55e}
.note-card.color-blue{border-left-color:#3b82f6}
.note-card.color-pink{border-left-color:#f43f5e}
.note-card.color-bookmark{border-left-color:#f59e0b}

.note-card-text{
  font-size:14px;font-weight:500;
  line-height:1.5;margin-bottom:6px;
  display:-webkit-box;-webkit-line-clamp:3;-webkit-box-orient:vertical;overflow:hidden;
}
.note-card-meta{
  font-size:12px;color:var(--muted);
  display:flex;justify-content:space-between;align-items:center;
}
.note-card-annotation{
  font-size:13px;color:var(--text);
  font-style:italic;margin-top:6px;
  padding:6px 10px;
  background:#fef3c7;border-radius:6px;
}
.note-card-delete{
  background:none;border:none;
  font-size:12px;color:var(--red);font-weight:600;
  cursor:pointer;font-family:inherit;
  padding:4px 8px;
}

/* ======================================================
   SHOP CARD (in library)
   ====================================================== */
.shop-card{
  background:var(--bg);
  border:2.5px dashed var(--border);
  border-radius:var(--radius);
  display:flex;flex-direction:column;
  align-items:center;justify-content:center;
  gap:8px;
  cursor:pointer;min-height:220px;
  transition:all .15s;
}
.shop-card:active{border-color:var(--navy);background:#eff6ff}
.shop-card-icon{font-size:36px}
.shop-card-text{
  font-size:14px;font-weight:700;color:var(--navy);
}
.shop-card-sub{
  font-size:12px;color:var(--muted);text-align:center;padding:0 12px;
}

/* ======================================================
   ARTICLE VIEW
   ====================================================== */
.article-view{
  position:fixed;inset:0;
  background:var(--bg);
  z-index:60;
  transform:translateX(100%);
  transition:transform .25s ease;
  overflow-y:auto;
  -webkit-overflow-scrolling:touch;
}
.article-view.open{transform:translateX(0)}

.article-header{
  position:sticky;top:0;z-index:2;
  background:var(--white);
  border-bottom:1px solid var(--border);
  padding:12px 16px;
}
[data-theme="dark"] .article-header{
  background:var(--card);border-color:var(--border);
}

.article-hero{
  width:100%;height:200px;overflow:hidden;
}
.article-hero img{
  width:100%;height:100%;object-fit:cover;
}

.article-content{
  padding:20px 18px 40px;
}
.article-content .feed-tag{
  margin-bottom:12px;
}
.article-content h1{
  font-size:22px;font-weight:800;line-height:1.3;
  color:var(--text);margin-bottom:8px;
}
.article-date{
  font-size:13px;color:var(--muted);margin-bottom:20px;
  padding-bottom:16px;border-bottom:1px solid var(--border);
}
.article-content h2{
  font-size:17px;font-weight:700;color:var(--text);
  margin:28px 0 10px;
}
.article-content h3{
  font-size:15px;font-weight:700;color:var(--text);
  margin:20px 0 8px;
}
.article-content p{
  font-size:15px;line-height:1.75;color:var(--text);
  margin-bottom:14px;
}
.article-content ul,
.article-content ol{
  margin:0 0 14px 20px;
  font-size:15px;line-height:1.75;color:var(--text);
}
.article-content li{margin-bottom:6px}
.article-content strong{font-weight:700}

.article-callout{
  background:var(--card);
  border-left:3px solid var(--navy);
  border-radius:6px;
  padding:14px 16px;
  margin:16px 0;
  font-size:14px;line-height:1.65;
}
[data-theme="dark"] .article-callout{
  background:#1a2233;
}

.article-content blockquote{
  border-left:3px solid var(--muted);
  padding:10px 16px;margin:16px 0;
  font-style:italic;color:var(--muted);
  font-size:14px;line-height:1.65;
}

.article-cta{
  background:var(--card);
  border:1.5px solid var(--border);
  border-radius:var(--radius);
  padding:20px;margin:24px 0;
  text-align:center;
}
.article-cta h3{
  font-size:16px;margin-bottom:8px;
}
.article-cta p{
  font-size:13px;color:var(--muted);margin-bottom:14px;
}

/* ======================================================
   STORE BACK BAR
   ====================================================== */
.store-back-bar{
  grid-column:1/-1;
  display:flex;align-items:center;justify-content:space-between;
  padding:4px 0 8px;
}
.store-back-bar .back-btn{
  display:flex;align-items:center;gap:6px;
  background:none;border:none;
  font-size:14px;font-weight:600;color:var(--navy);
  cursor:pointer;padding:8px 0;
}
.store-back-title{
  font-size:13px;font-weight:600;color:var(--muted);
}

/* ======================================================
   HOME FEED
   ====================================================== */
.home-feed{
  padding:0 16px 24px;
}
.home-feed.hidden{display:none}

.feed-featured{
  border-radius:var(--radius);overflow:hidden;
  background:var(--card);
  box-shadow:0 1px 3px rgba(0,0,0,.08);
  cursor:pointer;
  transition:box-shadow .15s;
  margin-bottom:20px;
}
.feed-featured:hover{box-shadow:0 2px 8px rgba(0,0,0,.12)}
.feed-featured-img{
  width:100%;height:180px;overflow:hidden;
}
.feed-featured-img img{
  width:100%;height:100%;object-fit:cover;
}
.feed-featured-body{
  padding:16px;
}
.feed-featured-title{
  font-size:18px;font-weight:800;line-height:1.3;
  color:var(--text);margin:8px 0;
}
.feed-featured-excerpt{
  font-size:14px;line-height:1.6;color:var(--muted);
  margin-bottom:10px;
}

.feed-tag{
  display:inline-block;
  padding:3px 10px;border-radius:4px;
  font-size:11px;font-weight:700;
  color:#fff;letter-spacing:0.3px;
  text-transform:uppercase;
}

.feed-meta{
  font-size:12px;color:var(--muted);font-weight:500;
}

.feed-section-title{
  font-size:13px;font-weight:700;text-transform:uppercase;
  letter-spacing:0.5px;color:var(--muted);
  margin:8px 0 12px;
}

.feed-card{
  background:var(--card);
  border-radius:var(--radius);
  padding:16px;
  margin-bottom:12px;
  cursor:pointer;
  box-shadow:0 1px 3px rgba(0,0,0,.06);
  transition:box-shadow .15s;
  border-left:3px solid transparent;
}
.feed-card:hover{box-shadow:0 2px 8px rgba(0,0,0,.10)}
.feed-card-title{
  font-size:15px;font-weight:700;line-height:1.35;
  color:var(--text);margin:6px 0;
}
.feed-card-excerpt{
  font-size:13px;line-height:1.55;color:var(--muted);
  margin-bottom:8px;
  display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden;
}

/* Dark mode feed */
[data-theme="dark"] .feed-featured{
  box-shadow:0 1px 3px rgba(0,0,0,.3);
}
[data-theme="dark"] .feed-card{
  box-shadow:0 1px 3px rgba(0,0,0,.2);
}

/* ======================================================
   PREVIEW LOCK
   ====================================================== */
.preview-lock{
  background:linear-gradient(to bottom, transparent 0%, var(--bg) 60%);
  padding:60px 20px 24px;
  text-align:center;
  margin-top:-40px;
  position:relative;
}
.preview-lock-icon{font-size:32px;margin-bottom:8px}
.preview-lock h3{font-size:16px;font-weight:800;margin-bottom:6px}
.preview-lock p{font-size:13px;color:var(--muted);margin-bottom:16px;line-height:1.5}
.preview-lock .btn{max-width:300px;margin:0 auto;display:block}

/* Preview button on detail page */
.detail-preview-btn{
  display:block;width:100%;padding:12px;margin-top:10px;
  background:var(--bg);color:var(--navy);
  border:1.5px solid var(--border);border-radius:var(--radius);
  font-size:14px;font-weight:600;cursor:pointer;
  transition:background .2s;
}
.detail-preview-btn:hover{background:#f5f5f4}
.detail-preview-btn:active{background:#e7e5e4}

/* Locked TOC items in preview mode */
.toc-locked{
  opacity:0.45;color:var(--muted) !important;
}

/* ======================================================
   STUDY MODE
   ====================================================== */
.study-view{padding:16px}

.streak-card{
  display:flex;align-items:center;gap:16px;
  background:linear-gradient(135deg,#ff9500,#ff5e3a);
  border-radius:var(--radius);
  padding:18px 20px;
  color:#fff;
  margin-bottom:24px;
}
.streak-flame{font-size:36px}
.streak-info{display:flex;flex-direction:column}
.streak-count{font-size:28px;font-weight:900;line-height:1}
.streak-label{font-size:12px;font-weight:600;opacity:.85}
.xp-badge{
  margin-left:auto;
  background:rgba(255,255,255,.2);
  border-radius:10px;padding:8px 14px;
  text-align:center;
}
.xp-count{display:block;font-size:22px;font-weight:900;line-height:1}
.xp-label{font-size:11px;font-weight:600;opacity:.85}

.study-section-title{
  font-size:16px;font-weight:800;
  margin-bottom:14px;color:var(--text);
}

.study-modes{
  display:flex;flex-direction:column;gap:10px;
  margin-bottom:28px;
}
.study-mode-card{
  display:flex;align-items:center;gap:14px;
  background:var(--white);
  border:1.5px solid var(--border);
  border-radius:var(--radius);
  padding:16px;
  cursor:pointer;text-align:left;
  transition:all .15s;
  font-family:inherit;
}
.study-mode-card:active{border-color:var(--navy);background:#eff6ff}
.study-mode-icon{font-size:28px;flex-shrink:0}
.study-mode-name{font-size:15px;font-weight:700;display:block}
.study-mode-desc{font-size:12px;color:var(--muted);display:block;margin-top:2px}

.progress-list{display:flex;flex-direction:column;gap:8px}
.progress-item{
  background:var(--white);border-radius:8px;
  padding:12px 16px;
  display:flex;align-items:center;justify-content:space-between;
  border:1px solid var(--border);
}
.progress-item-name{font-size:14px;font-weight:600}
.progress-item-bar{
  width:80px;height:6px;background:var(--border);
  border-radius:3px;overflow:hidden;
}
.progress-item-fill{height:100%;background:var(--navy);border-radius:3px}
.progress-item-pct{font-size:12px;font-weight:700;color:var(--navy);min-width:36px;text-align:right}

/* ======================================================
   QUIZ
   ====================================================== */
.quiz-view,.flashcard-view{padding:0}

.quiz-header{
  display:flex;align-items:center;gap:10px;
  padding:10px 16px;
  border-bottom:1px solid var(--border);
}
.quiz-progress-bar{
  flex:1;height:8px;background:var(--border);
  border-radius:4px;overflow:hidden;
}
.quiz-progress-fill{
  height:100%;background:#22c55e;border-radius:4px;
  transition:width .4s ease;width:0%;
}
.quiz-score{
  font-size:13px;font-weight:700;color:var(--navy);
  white-space:nowrap;
}

.quiz-body{padding:24px 20px}

.quiz-question{
  font-size:18px;font-weight:800;
  line-height:1.35;margin-bottom:6px;
}
.quiz-context{
  font-size:13px;color:var(--muted);
  margin-bottom:24px;font-weight:500;
}

.quiz-options{
  display:flex;flex-direction:column;gap:10px;
  margin-bottom:24px;
}
.quiz-option{
  display:flex;align-items:center;gap:12px;
  padding:16px;
  background:var(--white);
  border:2px solid var(--border);
  border-radius:var(--radius);
  font-size:15px;font-weight:600;
  cursor:pointer;font-family:inherit;
  text-align:left;
  transition:all .15s;
}
.quiz-option:active{border-color:var(--navy)}
.quiz-option.correct{
  border-color:#22c55e;background:#f0fdf4;color:#15803d;
}
.quiz-option.wrong{
  border-color:#ef4444;background:#fef2f2;color:#dc2626;
}
.quiz-option.dimmed{opacity:.5;pointer-events:none}
.quiz-option-letter{
  width:32px;height:32px;
  background:var(--bg);border-radius:50%;
  display:flex;align-items:center;justify-content:center;
  font-size:14px;font-weight:800;flex-shrink:0;
}
.quiz-option.correct .quiz-option-letter{background:#22c55e;color:#fff}
.quiz-option.wrong .quiz-option-letter{background:#ef4444;color:#fff}

.quiz-explanation{
  background:#eff6ff;border-radius:8px;
  padding:14px 16px;
  font-size:14px;line-height:1.6;
  color:#1e40af;
  margin-bottom:16px;
}
.quiz-explanation strong{color:var(--navy)}

.quiz-next-btn{
  width:100%;height:52px;
  border:none;border-radius:var(--radius);
  background:var(--navy);color:#fff;
  font-size:16px;font-weight:700;
  cursor:pointer;font-family:inherit;
}
.quiz-next-btn:active{background:#001a4a}

/* Quiz results */
.quiz-results{text-align:center;padding:40px 20px}
.quiz-results-icon{font-size:64px;margin-bottom:16px}
.quiz-results h2{font-size:24px;font-weight:900;margin-bottom:4px}
.quiz-results .quiz-results-sub{font-size:15px;color:var(--muted);margin-bottom:24px}
.quiz-results-stats{
  display:flex;gap:16px;justify-content:center;margin-bottom:32px;
}
.quiz-stat{
  background:var(--bg);border-radius:var(--radius);
  padding:16px 20px;text-align:center;min-width:80px;
}
.quiz-stat-val{display:block;font-size:24px;font-weight:900;color:var(--navy)}
.quiz-stat-label{font-size:11px;color:var(--muted);font-weight:600}

/* ======================================================
   FLASHCARDS
   ====================================================== */
.flashcard-body{
  flex:1;display:flex;align-items:center;justify-content:center;
  padding:20px;
}
.flashcard{
  width:100%;max-width:340px;
  min-height:280px;
  background:var(--white);
  border:2px solid var(--border);
  border-radius:16px;
  box-shadow:0 4px 20px rgba(0,0,0,.08);
  display:flex;align-items:center;justify-content:center;
  padding:32px 24px;
  text-align:center;
  cursor:pointer;
  transition:transform .3s;
  transform-style:preserve-3d;
  position:relative;
}
.flashcard.flipped{transform:rotateY(180deg)}
.flashcard-front,.flashcard-back{
  backface-visibility:hidden;
  position:absolute;inset:0;
  display:flex;flex-direction:column;
  align-items:center;justify-content:center;
  padding:32px 24px;
}
.flashcard-back{transform:rotateY(180deg)}
.flashcard-label{
  font-size:11px;font-weight:700;
  text-transform:uppercase;letter-spacing:1px;
  color:var(--muted);margin-bottom:12px;
}
.flashcard-term{font-size:20px;font-weight:800;line-height:1.3}
.flashcard-def{font-size:16px;line-height:1.6;color:var(--muted)}
.flashcard-ref{
  font-size:11px;color:var(--muted);margin-top:12px;font-weight:500;
}

.flashcard-counter{font-size:14px;font-weight:600;color:var(--muted)}

.flashcard-nav{
  display:flex;align-items:center;justify-content:space-between;
  padding:12px 16px;
  border-top:1px solid var(--border);
}
.flash-flip-btn{
  background:var(--navy);color:#fff;
  border:none;border-radius:8px;
  padding:10px 24px;font-size:14px;font-weight:700;
  cursor:pointer;font-family:inherit;
}
.flash-flip-btn:active{background:#001a4a}

/* Toast */
.toast{
  position:fixed;bottom:32px;left:50%;
  transform:translateX(-50%) translateY(16px);
  background:var(--text);color:#fff;
  padding:12px 24px;border-radius:50px;
  font-size:14px;font-weight:600;
  z-index:200;opacity:0;transition:all .25s;
  pointer-events:none;white-space:nowrap;
}
.toast.show{opacity:1;transform:translateX(-50%) translateY(0)}

/* ======================================================
   RESPONSIVE
   ====================================================== */
@media(min-width:600px){
  .book-grid{grid-template-columns:repeat(3,1fr);gap:18px;padding:18px 20px 40px}
}
@media(min-width:900px){
  .book-grid{grid-template-columns:repeat(4,1fr);max-width:960px;margin:0 auto}
  .detail-cover{width:220px}
}