/**************************************
 * THEME TOKENS
 **************************************/
:root{
  --bg: #0f1115;
  --elev: #151923;
  --text: #e6e6e6;
  --muted:#93a0b4;
  --primary:#5b9dff;
  --danger:#ff6b6b;
  --border:#2a3242;

  /* Mobile helpers */
  --bg-2: var(--elev);
  --card: var(--elev);

  /* Sidebar */
  --sidebar-w: 240px;
  --sidebar-bg: #0b1230;
  --sidebar-text: #c8d0e2;
  --sidebar-muted:#9aa4bc;
  --sidebar-active:#3351ff;
  --sidebar-hover: rgba(255,255,255,.08);

  /* Effects */
  --ring: 0 0 0 3px rgba(91,157,255,.35);

  /* Breadcrumb/Tree color tokens (dark defaults) */
  --pill-bg: #10131b;
  --pill-text: #bcd1ff;
  --tree-fg: #d7def0;
}
:root.light{
  --bg:#f6f8fc;
  --elev:#ffffff;
  --text:#1b2430;
  --muted:#5b677a;
  --primary:#2f6bff;
  --danger:#e14b4b;
  --border:#e5e9f1;

  --bg-2: var(--elev);
  --card: var(--elev);

  --sidebar-bg:#ffffff;
  --sidebar-text:#2a3550;
  --sidebar-muted:#6b7691;
  --sidebar-active:#2f6bff;
  --sidebar-hover: rgba(0,0,0,.06);

  --ring: 0 0 0 3px rgba(47,107,255,.25);

  --pill-bg: #eef3ff;
  --pill-text: #1f3a8a;
  --tree-fg: #334155;
}

/**************************************
 * GLOBAL
 **************************************/
*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0;
  background:var(--bg);
  color:var(--text);
  font:16px/1.5 system-ui, -apple-system, Segoe UI, Roboto, "Helvetica Neue", Arial, "Noto Sans", "Apple Color Emoji","Segoe UI Emoji";
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
/* Khi có .sidebar, nội dung bị đẩy sang phải đúng theo --sidebar-w */
body:has(.sidebar){ padding-left: var(--sidebar-w); }

a{color:inherit; text-decoration:none}
button,input,select,textarea{font:inherit; color:inherit}
button{cursor:pointer}
img{max-width:100%; display:block}

/**************************************
 * SIDEBAR
 **************************************/
.sidebar{
  position: fixed; inset: 0 auto 0 0;
  width: var(--sidebar-w);
  background: var(--sidebar-bg);
  border-right:1px solid var(--border);
  display:flex; flex-direction:column; gap:8px; z-index: 30;
}
.sidebar__logo{ display:flex; align-items:center; gap:10px; padding:18px 16px 10px; color:var(--sidebar-text); }
.sidebar__logo .logo{ font-size:22px; }
.sidebar__logo h2{ font-size:18px; margin:0; }
.sidebar__nav{ display:flex; flex-direction:column; padding:6px; }
.sidebar__nav a{
  display:flex; align-items:center; gap:12px; padding:10px 12px; margin:2px 4px;
  color:var(--sidebar-text);
  border-radius:8px; transition: background .2s, color .2s, transform .06s ease;
  outline: none; position: relative;
}
.sidebar__nav a:hover{ background: var(--sidebar-hover); color:#fff; }
.sidebar__nav a:active{ transform: translateY(1px); }
.sidebar__nav a .icon{ width:20px; display:inline-flex; justify-content:center; opacity:.9; }
.sidebar__nav a .label{ flex:1; }
.sidebar__group{ margin:4px 6px; }
.sidebar__group>summary{
  list-style:none; cursor:pointer; display:flex; align-items:center; gap:12px;
  padding:10px 12px; border-radius:8px; color:var(--sidebar-text);
  transition: background .2s, color .2s;
  outline: none;
}
.sidebar__group>summary::-webkit-details-marker{ display:none; }
.sidebar__group>summary:hover{ background: var(--sidebar-hover); color:#fff; }
.sidebar__group[open]>summary{ background: var(--sidebar-hover); }
.submenu{ display:flex; flex-direction:column; padding:6px 0 6px 32px; gap:2px; }
.submenu a{ display:flex; align-items:center; gap:10px; padding:8px 10px; border-radius:8px; color:var(--sidebar-text); }
.submenu a:hover{ background: var(--sidebar-hover); color:#fff; }

/* Focus ring */
.sidebar__nav a:focus-visible,
.sidebar__group>summary:focus-visible,
.submenu a:focus-visible,
button:focus-visible,
input:focus-visible,
select:focus-visible,
.dialog:focus-visible { box-shadow: var(--ring); }

/* Thu gọn label khi <900px nhưng vẫn desktop */
@media (max-width: 900px){
  :root{ --sidebar-w: 72px; }
  .sidebar__logo h2{ display:none; }
  .sidebar__nav a{ justify-content:center; gap:8px; }
  .sidebar__nav a .label{ display:none; }
}

/* Nhấn mạnh active (gradient + thanh chỉ mục) */
.sidebar__nav a.active{
  background: linear-gradient(90deg, rgba(51,81,255,.18), rgba(51,81,255,0));
  color:#fff; font-weight:600;
}
.sidebar__nav a.active::before{
  content:"";
  position:absolute; left:0; top:8px; bottom:8px;
  width:4px; border-radius:4px;
  background: var(--sidebar-active,#3351ff);
  box-shadow: 0 0 0 2px rgba(51,81,255,.25);
}

/**************************************
 * TOPBAR (phần bên phải)
 **************************************/
.topbar{
  position:sticky; top:0; z-index: 25;
  display:flex; align-items:center; justify-content:space-between;
  padding:12px 16px; gap:12px; background:var(--elev); border-bottom:1px solid var(--border);
}
.brand{display:flex; align-items:center; gap:10px}
.brand .logo{font-size:22px}
.brand h1{font-size:18px; margin:0}

.actions{display:flex; align-items:center; gap:8px; flex-wrap:wrap}
.btn{
  background:var(--bg); border:1px solid var(--border); color:var(--text);
  padding:9px 12px; border-radius:10px; cursor:pointer; line-height:1; user-select:none;
  transition: filter .12s ease, transform .06s ease, background-color .12s ease, color .12s ease, border-color .12s ease;
  outline: none;
}
.btn:hover{filter:brightness(1.08)}
.btn:active{transform:translateY(1px)}
.btn:focus-visible{ box-shadow: var(--ring); }
.btn[disabled]{ opacity:.55; cursor:not-allowed; filter:none; transform:none; }
.btn-primary{background:var(--primary); border-color:transparent; color:#fff}
.btn-danger{background:var(--danger); border-color:transparent; color:#fff}
.btn-ghost{background:transparent}

.search-group{
  display:flex; align-items:stretch; gap:6px; background:var(--bg);
  border:1px solid var(--border); border-radius:12px; padding:6px;
}
.search-group input{
  background:transparent; border:none; color:var(--text); outline:none; min-width:240px;
}
.search-group input::placeholder{ color: color-mix(in oklab, var(--text) 45%, transparent); }

/**************************************
 * LEARNING: TOOLBAR + CONTENT
 **************************************/
.learning-wrap{ display:flex; flex-direction:column; min-height: calc(100vh - 60px); }

.learning-toolbar{
  position: sticky; top: 60px; /* nằm dưới topbar ~ 60px */
  display:flex; align-items:center; justify-content:space-between; gap:12px;
  padding:10px 16px; background:var(--elev); border-bottom:1px solid var(--border);
  z-index:20;
}
.tools-left,.tools-right{display:flex; align-items:center; gap:10px}
.muted{color:var(--muted)}

.seg{
  display:flex; gap:6px; padding:6px;
  background:var(--bg-2); border:1px solid var(--border); border-radius:999px;
}
.seg__btn{
  background:transparent; color:var(--muted); border:0;
  padding:6px 12px; border-radius:999px;
}
.seg__btn.is-active{background:var(--primary); color:#fff}

/* 2 cột: Tags (trái) | List (phải) */
.learning-content{
  display: grid; 
  gap: var(--space-xl); 
  padding: var(--space-xl);
  grid-template-columns: 220px 1fr;
  height: calc(100vh - 80px - 60px); /* Trừ topbar và toolbar */
  overflow: hidden; /* Ngăn scroll ở container cha */
  max-width: 1600px;
  margin: 0 auto;
}
.learning-side{ 
  position: sticky; 
  top: calc(60px + 46px); 
  align-self: start; 
  height: fit-content; 
  overflow-y: auto; /* Cho phép scroll trong sidebar nếu cần */
  /* Ẩn thanh scroll */
  scrollbar-width: none; /* Firefox */
  -ms-overflow-style: none; /* IE and Edge */
}

.learning-side::-webkit-scrollbar {
  display: none; /* Chrome, Safari, Opera */
}
.learning-main{
  overflow-y: auto; /* Cho phép scroll trong danh sách items */
  height: 100%; /* Chiếm toàn bộ chiều cao của grid cell */
  /* Ẩn thanh scroll */
  scrollbar-width: none; /* Firefox */
  -ms-overflow-style: none; /* IE and Edge */
}

.learning-main::-webkit-scrollbar {
  display: none; /* Chrome, Safari, Opera */
}
.panel{
  background:var(--elev); border:1px solid var(--border);
  border-radius:14px; padding:12px; margin-bottom:12px;
}
.panel__title{margin:0 0 10px 0; font-size:15px}

.tag-cloud{display:flex; flex-wrap:wrap; gap:8px}
.tag{ padding:4px 10px; border:1px solid var(--border); border-radius:999px; background:transparent; color:var(--text); }
.tag.is-active{background:var(--primary); color:#fff; border-color:transparent}

/* Empty */
.empty{
  padding:24px; text-align:center; color:var(--muted);
  border:1px dashed var(--border); border-radius:14px; background:var(--bg-2);
}

/**************************************
 * MODERN LIST VIEW
 **************************************/
#item-list { 
  list-style: none; 
  margin: 0; 
  padding: 0; 
  display: flex; 
  flex-direction: column; 
  gap: var(--space-lg); 
}

.list-item{
  display: grid; 
  grid-template-columns: 100px 1fr; 
  gap: var(--space-lg);
  align-items: start; 
  padding: var(--space-xl); 
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  background: var(--elev);
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  position: relative;
  overflow: hidden;
}
.list-item:hover{ 
  transform: translateY(-4px);
  box-shadow: var(--shadow-xl);
  border-color: var(--primary);
}
.list-item:hover::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--gradient-primary);
}

.list-thumb{
  width: 100px; 
  height: 140px; 
  border: 1px solid var(--border); 
  border-radius: var(--radius-lg);
  background: var(--bg) center/cover no-repeat; 
  overflow: hidden; 
  cursor: pointer;
  display: grid; 
  place-items: center; 
  color: var(--muted); 
  font-size: 24px;
  transition: all 0.2s ease;
  box-shadow: var(--shadow-sm);
}
.list-thumb:hover {
  transform: scale(1.05);
  box-shadow: var(--shadow-md);
}
/* Ảnh trong thumbnail */
.list-thumb img{
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.list-main{ 
  display: flex; 
  flex-direction: column; 
  gap: var(--space-sm); 
  min-width: 0; 
}

.item-title{ 
  margin: 0; 
  font-size: 18px; 
  font-weight: 700; 
  line-height: 1.3; 
}
.item-title a{ 
  color: var(--primary); 
  text-decoration: none; 
  transition: all 0.2s ease;
}
.item-title a:hover{ 
  color: var(--primary-hover);
  text-decoration: underline; 
}

.item-notes{
  margin: var(--space-sm) 0 0;
  color: var(--text-secondary);
  font-size: 14px;
  line-height: 1.5;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.item-tags{ 
  display: flex; 
  flex-wrap: wrap; 
  gap: var(--space-sm); 
  margin-top: var(--space-sm);
}
.item-tags .tag{
  font-size: 12px; 
  padding: 4px 10px; 
  border-radius: var(--radius-full);
  border: 1px solid var(--border); 
  background: var(--elev-2);
  color: var(--text-secondary);
  transition: all 0.2s ease;
  font-weight: 500;
}
.item-tags .tag:hover {
  background: var(--primary);
  color: white;
  border-color: transparent;
  transform: translateY(-1px);
}

/* Selection mode */
.list-item.is-selected{
  outline: 2px solid var(--primary);
  box-shadow: 0 0 0 4px rgba(99, 102, 241, 0.2);
  background: var(--elev-2);
}

/**************************************
 * DIALOG (thêm tài liệu)
 **************************************/
.dialog{
  border:none; padding:0; border-radius:16px; width:min(560px, 92vw);
  background:var(--elev); color:var(--text); border:1px solid var(--border);
  max-height: 90vh; overflow: hidden; z-index: 50;
}
.dialog::backdrop{background:rgba(0,0,0,.5)}
.dialog__content{padding:16px; max-height:90vh; overflow:auto}
.dialog__title{margin:0 0 12px; font-size:18px}
.form-row{display:flex; flex-direction:column; gap:6px; margin-bottom:12px}
.form-row input,.form-row select,.form-row textarea{
  background:var(--bg); border:1px solid var(--border); color:var(--text);
  padding:10px 12px; border-radius:10px; outline: none;
}
.form-row input:focus-visible,.form-row select:focus-visible,.form-row textarea:focus-visible{ box-shadow: var(--ring); }
.dialog-actions{ display:flex; gap:8px; justify-content:flex-end; margin-top:14px; }

/* 🔑 Login styles (chỉ thêm cho nút & dialog đăng nhập/đăng ký) */
#btn-login[data-state="in"]{
  /* Khi đã đăng nhập: dùng style nút thường, không primary */
  background: var(--bg);
  border: 1px solid var(--border);
  color: var(--text);
}
#btn-login[data-state="in"]:hover{ filter: brightness(1.08); }

#login-dialog h3, #signup-dialog h3 {
  margin:0 0 12px;
  font-size:18px;
  text-align:center;
}
#login-dialog .form-error,
#signup-dialog .form-error{
  color: var(--danger);
  font-size: 14px;
  margin: 6px 0;
}
#login-dialog .dialog-actions,
#signup-dialog .dialog-actions{
  justify-content: space-between;
}
#login-dialog a,
#signup-dialog a{
  color: var(--primary);
  text-decoration: none;
}
#login-dialog a:hover,
#signup-dialog a:hover{
  text-decoration: underline;
}

/**************************************
 * SCROLLBARS
 **************************************/
*::-webkit-scrollbar{ width:10px; height:10px }
*::-webkit-scrollbar-track{ background: transparent }
*::-webkit-scrollbar-thumb{ background: color-mix(in oklab, var(--text) 20%, transparent); border-radius: 999px; border: 2px solid transparent; background-clip: padding-box; }

/**************************************
 * RESPONSIVE
 **************************************/
@media (max-width: 1200px){
  .learning-content{grid-template-columns: 180px 1fr}
}
@media (max-width: 1000px){
  .learning-content{grid-template-columns: 1fr}
  .learning-side{display: none} /* Ẩn tags trên tablet */
}
@media (max-width: 900px){
  .learning-content{
    grid-template-columns: 1fr;
    height: calc(100vh - 60px - 46px - 20px); /* Thêm margin cho mobile */
  }
  .learning-side{
    position: static;
    height: auto;
    max-height: 200px; /* Giới hạn chiều cao sidebar trên mobile */
  }
}
@media (max-width: 520px){
  .search-group input{min-width:0; width:160px}
  #item-list{ gap:12px; }
}

/**************************************
 * LIGHT THEME TWEAKS
 **************************************/
:root.light .sidebar__nav a{ color: var(--sidebar-text); }
:root.light .sidebar__nav a:hover{ background: var(--sidebar-hover); color:var(--sidebar-text); }
:root.light .sidebar__nav a:focus-visible{ box-shadow: 0 0 0 2px rgba(47,107,255,.45); }
:root.light .sidebar__nav a.active{
  background: linear-gradient(90deg, rgba(47,107,255,.14), rgba(47,107,255,0));
  color: var(--sidebar-text);
}
:root.light .sidebar__nav a.active::before{
  background: var(--sidebar-active);
  box-shadow: 0 0 0 2px rgba(47,107,255,.2);
}
:root.light .sidebar__group[open] > summary{ background: rgba(0,0,0,.04); }
:root.light .submenu a:hover{ background: rgba(0,0,0,.06); }



/* === Login button: style giống .site-topbar__btn trong mẫu === */
#btn-login{
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  border: 1px solid var(--border, #2a3242);
  border-radius: 10px;
  background: var(--bg, #0f1115);
  color: var(--text, #e6e6e6);
  cursor: pointer;
  line-height: 1;
  transition: background .12s ease, filter .12s ease, transform .06s ease, border-color .12s ease;
}
#btn-login:hover{ background: color-mix(in oklab, var(--bg) 88%, #fff 12%); }
#btn-login:active{ transform: translateY(1px); }
#btn-login:focus-visible{ box-shadow: var(--ring, 0 0 0 3px rgba(91,157,255,.35)); }

/* Khi đã đăng nhập: bỏ màu primary, giữ style trung tính + rút gọn email bằng JS */
#btn-login[data-state="in"]{
  background: var(--bg, #0f1115);
  border-color: var(--border, #2a3242);
  color: var(--text, #e6e6e6);
}

/* Khi chưa đăng nhập: cho phép dùng phiên bản “nổi bật” nếu có .btn-primary đi kèm */
#btn-login[data-state="out"].btn-primary{
  background: var(--primary, #5b9dff);
  border-color: transparent;
  color: #fff;
}
#btn-login[data-state="out"].btn-primary:hover{
  filter: brightness(1.06);
}

/* === Dialog đăng nhập / đăng ký: căn giữa tiêu đề, form-row theo mẫu, link xanh === */
#login-dialog, #signup-dialog{
  border: none;
  border-radius: 16px;
  background: var(--elev, #151923);
  color: var(--text, #e6e6e6);
  border: 1px solid var(--border, #2a3242);
  width: min(560px, 92vw);
  max-height: 90vh;
  overflow: hidden;
}
#login-dialog::backdrop, #signup-dialog::backdrop{
  background: rgba(0,0,0,.5);
}
#login-dialog form, #signup-dialog form{
  padding: 16px;
  max-height: 90vh;
  overflow: auto;
}
#login-dialog h3, #signup-dialog h3{
  margin: 0 0 12px;
  font-size: 18px;
  text-align: center;
}
#login-dialog .form-row,
#signup-dialog .form-row{
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-bottom: 12px;
}
#login-dialog input,
#signup-dialog input{
  background: var(--bg, #0f1115);
  border: 1px solid var(--border, #2a3242);
  color: var(--text, #e6e6e6);
  padding: 10px 12px;
  border-radius: 10px;
  outline: none;
}
#login-dialog input:focus-visible,
#signup-dialog input:focus-visible{
  box-shadow: var(--ring, 0 0 0 3px rgba(91,157,255,.35));
}
#login-dialog .dialog-actions,
#signup-dialog .dialog-actions{
  display: flex;
  gap: 8px;
  justify-content: space-between;
  margin-top: 14px;
}
#login-dialog .form-error,
#signup-dialog .form-error{
  color: var(--danger, #ff6b6b);
  font-size: 14px;
  margin: 6px 0;
}
#login-dialog a, #signup-dialog a{
  color: var(--primary, #5b9dff);
  text-decoration: none;
}
#login-dialog a:hover, #signup-dialog a:hover{
  text-decoration: underline;
}

/* Mobile full-screen dialog giống mẫu */
@media (max-width: 960px){
  #login-dialog, #signup-dialog{
    width: 100vw;
    height: 100dvh;
    max-width: none;
    margin: 0;
    border-radius: 0;
    background: var(--bg-2, var(--elev));
    color: inherit;
  }
  #login-dialog form, #signup-dialog form{ padding: 14px; }
}

/* (Tuỳ chọn) Nếu bạn dùng topbar chung kiểu .site-topbar trong trang khác, 
   có thể áp dụng cho .topbar hiện tại để đồng bộ chiều cao */
.topbar{ min-height: 56px; }