/* Giao diện dùng chung cho các ứng dụng (/judge, /teamsync, /tai-khoan, /admin, /projects/*).
   Phong cách hiện đại: tiêu đề Plus Jakarta Sans (đậm, chữ khít), giao diện Inter, số liệu & code JetBrains Mono. Màu nền/chữ lấy từ home.css nên tự theo Sáng/Tối. */
:root {
  --font-ui: "Inter", "Be Vietnam Pro", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-display: "Plus Jakarta Sans", "Inter", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  --radius: 7px;
  --radius-lg: 11px;
  --surface: #ffffff;
  --surface-2: #f6f6f4;
  --rule: #1a1a1a;
  --ok: #157a3d;
  --bad: #b42318;
  --warn: #9a6200;
  --info: #1f4fbf;
  --ok-bg: #edf7f0; --bad-bg: #fbeeec; --warn-bg: #fbf4e6; --info-bg: #edf2fc;
  --focus: #0f766e;
  --shadow: 0 1px 2px rgba(0, 0, 0, .04), 0 12px 32px rgba(0, 0, 0, .08);
  --ease: cubic-bezier(.2, .7, .2, 1);
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --surface: #111111; --surface-2: #161616; --rule: #e8e8e8;
    --ok: #5fd08a; --bad: #ff8a7a; --warn: #f0b955; --info: #8fb4ff;
    --ok-bg: #12241a; --bad-bg: #2a1512; --warn-bg: #2a2110; --info-bg: #121c30;
    --focus: #5eead4;
    --shadow: 0 1px 2px rgba(0, 0, 0, .4), 0 16px 40px rgba(0, 0, 0, .5);
  }
}
:root[data-theme="dark"] {
  --surface: #111111; --surface-2: #161616; --rule: #e8e8e8;
  --ok: #5fd08a; --bad: #ff8a7a; --warn: #f0b955; --info: #8fb4ff;
  --ok-bg: #12241a; --bad-bg: #2a1512; --warn-bg: #2a2110; --info-bg: #121c30;
  --focus: #5eead4;
  --shadow: 0 1px 2px rgba(0, 0, 0, .4), 0 16px 40px rgba(0, 0, 0, .5);
}

/* Thanh điều hướng giữ phông của site; phần ứng dụng dùng bộ phông riêng. */
.app-body main, .app-body dialog, .app-body .toast-region, .app-body .ts-tip, .app-body .app-footer {
  font-family: var(--font-ui);
  font-feature-settings: "cv11" 1, "ss03" 1; /* Inter: chữ a một tầng, số dễ đọc */
}
.app-body main { font-size: 15px; line-height: 1.6; }
.app-body main h1, .app-body main h2, .app-body dialog h2 { font-family: var(--font-display); font-weight: 700; letter-spacing: -.025em; }
.app-body main h1 { font-size: clamp(1.9rem, 4vw, 2.6rem); line-height: 1.08; margin: 0; font-weight: 800; letter-spacing: -.035em; }
.app-body main h2 { font-size: 1.25rem; line-height: 1.25; }
.app-body main h3 { font-family: var(--font-ui); font-weight: 600; font-size: .95rem; }
.app-body main .subtitle { font-family: var(--font-ui); font-style: normal; font-size: 1.02rem; color: var(--fg-muted); }
.mono, .app-body code, .app-body pre, .app-body kbd { font-family: var(--font-mono); }
.num, .tabular { font-variant-numeric: tabular-nums; }

/* ---------- Thanh ứng dụng riêng (UniJudge, TeamSync) — tách khỏi header của trang chủ ---------- */
.appbar {
  position: sticky; top: 0; z-index: 30;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  -webkit-backdrop-filter: saturate(1.4) blur(10px); backdrop-filter: saturate(1.4) blur(10px);
  border-bottom: 1px solid var(--border);
  font-family: var(--font-ui);
}
.appbar-inner { max-width: 1100px; margin: 0 auto; padding: 0 24px; height: 56px; display: flex; align-items: center; gap: 28px; }
.appbar-brand { display: inline-flex; align-items: center; gap: 10px; color: var(--fg-deep); text-decoration: none; flex-shrink: 0; }
.appbar-mark { display: inline-grid; place-items: center; width: 28px; height: 28px; border-radius: 7px; background: var(--fg-deep); color: var(--bg); }
.appbar-mark svg { width: 18px; height: 18px; }
.appbar-name { font-family: var(--font-display); font-size: 1.12rem; font-weight: 800; letter-spacing: -.03em; line-height: 1; }
.appbar-nav { display: flex; align-items: stretch; gap: 22px; height: 100%; }
.appbar-nav a {
  position: relative; display: inline-flex; align-items: center; white-space: nowrap;
  color: var(--fg-muted); text-decoration: none; font-size: .875rem; font-weight: 500; transition: color .15s;
}
.appbar-nav a:hover, .appbar-nav a[aria-current="page"] { color: var(--fg-deep); }
.appbar-nav a[aria-current="page"]::after { content: ""; position: absolute; left: 0; right: 0; bottom: -1px; height: 2px; background: var(--fg-deep); }
.appbar-end { margin-left: auto; display: flex; align-items: center; gap: 6px; }
.appbar-icon {
  display: inline-grid; place-items: center; width: 34px; height: 34px; border-radius: var(--radius-lg);
  background: none; border: 1px solid transparent; color: var(--fg-muted); cursor: pointer; transition: color .15s, border-color .15s;
}
.appbar-icon:hover { color: var(--fg-deep); border-color: var(--border); }
.appbar-icon svg { width: 18px; height: 18px; }
.appbar-slot:empty { width: 34px; }

/* Menu tài khoản */
.appbar-menu { position: relative; }
.appbar-menu > summary { list-style: none; }
.appbar-menu > summary::-webkit-details-marker { display: none; }
.appbar-user {
  display: inline-flex; align-items: center; gap: 8px; height: 34px; padding: 0 8px 0 4px; border-radius: 999px;
  border: 1px solid var(--border); color: var(--fg-deep); font-size: .85rem; cursor: pointer; transition: border-color .15s;
}
.appbar-user:hover, .appbar-menu[open] > .appbar-user { border-color: var(--fg-muted); }
.appbar-user .userbar-avatar { width: 26px; height: 26px; background: var(--fg-deep); color: var(--bg); border: 0; }
.appbar-user-name { max-width: 160px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.appbar-caret { width: 12px; height: 12px; color: var(--fg-muted); transition: transform .15s; }
.appbar-menu[open] .appbar-caret { transform: rotate(180deg); }
.appbar-menu-list {
  position: absolute; right: 0; top: calc(100% + 8px); min-width: 230px; padding: 6px; display: grid;
  background: var(--bg); border: 1px solid var(--border); border-radius: var(--radius-lg); box-shadow: var(--shadow);
  animation: menu-in .14s var(--ease) both;
}
@keyframes menu-in { from { opacity: 0; transform: translateY(-4px); } }
.appbar-menu-head { display: grid; padding: 8px 10px 10px; margin-bottom: 4px; border-bottom: 1px solid var(--border); font-size: .875rem; }
.appbar-menu-head .mono { font-size: .75rem; color: var(--fg-muted); }
.appbar-menu-item {
  display: block; width: 100%; text-align: left; padding: 8px 10px; border-radius: var(--radius); border: 0; background: none;
  font: inherit; font-size: .875rem; color: var(--fg-deep); text-decoration: none; cursor: pointer;
}
.appbar-menu-item:hover, .appbar-menu-item:focus-visible { background: var(--surface-2); }
.appbar-menu-list hr { border: 0; border-top: 1px solid var(--border); margin: 4px 0; }

.appfoot { display: flex; justify-content: space-between; gap: 12px; flex-wrap: wrap; }
.appfoot a { color: inherit; }

@media (max-width: 640px) {
  .appbar-inner { padding: 0 16px; gap: 16px; height: 52px; }
  .appbar-name { font-size: 1.15rem; }
  .appbar-nav { gap: 12px; }
  .appbar-inner { gap: 12px; }
  .appbar-user-name, .appbar-caret { display: none; }
  .appbar-user { padding: 0 3px; }
}
@media (max-width: 420px) {
  .appbar-nav a[href^="../projects/"], .appbar-nav a[href^="../../projects/"] { display: none; }
  .appbar-name { display: none; }
  .appbar-end { gap: 2px; }
}

/* Khung trang ứng dụng */
main.app-main { max-width: 1100px; padding-top: 28px; }
footer.app-footer { max-width: 1100px; }
.app-body { min-height: 100dvh; }

/* Chuyển trang mượt: nội dung chỉ hiện khi ứng dụng đã dựng xong (tránh nháy "Đang tải…" rồi nhảy bố cục). */
main.app-main { view-transition-name: app-content; opacity: 0; transition: opacity .22s var(--ease); }
main.app-main.is-ready { opacity: 1; }
::view-transition-old(app-content) { animation: app-leave .14s ease-in both; }
::view-transition-new(app-content) { animation: none; }
@keyframes app-leave { to { opacity: 0; } }
.swap-in { animation: swap-in .2s var(--ease) both; }
@keyframes swap-in { from { opacity: 0; transform: translateY(4px); } }

.app-crumbs { display: flex; flex-wrap: wrap; align-items: center; gap: 8px; margin: 0; color: var(--fg-muted); font-size: .78rem; letter-spacing: .06em; text-transform: uppercase; }
.prose .app-crumbs a { color: var(--fg-muted); border-bottom: 0; }
.prose .app-crumbs a:hover { color: var(--fg-deep); }
.app-toprow { display: flex; justify-content: space-between; align-items: center; gap: 8px 16px; flex-wrap: wrap; margin-bottom: 14px; padding-bottom: 10px; border-bottom: 1px solid var(--border); }
.app-head { display: flex; flex-wrap: wrap; align-items: flex-end; justify-content: space-between; gap: 14px 28px; margin-bottom: 24px; }
.app-head .subtitle { margin: 8px 0 0; }

[hidden] { display: none !important; }
:focus-visible { outline: 2px solid var(--focus); outline-offset: 2px; }

/* Nút */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 6px;
  min-height: 34px; padding: 6px 14px; border-radius: var(--radius);
  border: 1px solid var(--border); background: var(--surface); color: var(--fg-deep);
  font-family: var(--font-ui); font-weight: 500; font-size: .875rem; line-height: 1.3; letter-spacing: .005em;
  cursor: pointer; text-decoration: none; white-space: nowrap;
  transition: background-color .15s, border-color .15s, color .15s, opacity .15s;
}
.btn:hover { border-color: var(--fg-deep); }
.btn:active { transform: translateY(1px); }
.btn:disabled { opacity: .45; cursor: not-allowed; transform: none; }
.btn-primary { background: var(--fg-deep); border-color: var(--fg-deep); color: var(--bg); }
.btn-primary:hover { opacity: .86; }
.btn-accent { background: var(--accent); border-color: var(--accent); color: var(--bg); }
.btn-accent:hover { opacity: .86; border-color: var(--accent); }
.btn-ghost { background: none; border-color: transparent; color: var(--fg-muted); }
.btn-ghost:hover { color: var(--fg-deep); border-color: transparent; background: var(--surface-2); }
.btn-danger { color: var(--bad); }
.btn-danger:hover { border-color: var(--bad); }
.btn-sm { min-height: 28px; padding: 3px 10px; font-size: .8rem; }
.btn svg, .icon { width: 15px; height: 15px; flex: none; }
.prose a.btn { border-bottom: 1px solid var(--border); }

/* Ô nhập */
.field { display: grid; gap: 6px; font-size: .9rem; }
.field > span, .label { color: var(--fg-muted); font-size: .7rem; font-weight: 500; letter-spacing: .08em; text-transform: uppercase; }
.input, .select, .textarea {
  width: 100%; min-height: 36px; padding: 7px 10px; border-radius: var(--radius);
  border: 1px solid var(--border); background: var(--surface); color: var(--fg-deep);
  font: inherit; font-size: .9rem; transition: border-color .15s, box-shadow .15s;
}
.textarea { min-height: 80px; resize: vertical; line-height: 1.55; }
.textarea.mono, .input.mono { font-family: var(--font-mono); font-size: .84rem; }
.input:hover, .select:hover, .textarea:hover { border-color: var(--fg-muted); }
.input:focus, .select:focus, .textarea:focus { outline: none; border-color: var(--fg-deep); box-shadow: 0 0 0 3px color-mix(in srgb, var(--fg-deep) 10%, transparent); }

/* Nhãn: chữ nhỏ có viền mảnh — màu chỉ để mang nghĩa */
.chip {
  display: inline-flex; align-items: center; gap: 5px; padding: 0 6px; border-radius: 3px;
  border: 1px solid var(--border); background: transparent; color: var(--fg);
  font-size: .74rem; line-height: 1.65; white-space: nowrap; letter-spacing: .01em;
}
.chip-ok { color: var(--ok); border-color: color-mix(in srgb, var(--ok) 35%, transparent); }
.chip-bad { color: var(--bad); border-color: color-mix(in srgb, var(--bad) 35%, transparent); }
.chip-warn { color: var(--warn); border-color: color-mix(in srgb, var(--warn) 35%, transparent); }
.chip-info { color: var(--info); border-color: color-mix(in srgb, var(--info) 35%, transparent); }
.chip-muted { color: var(--fg-muted); }
/* Chấm trạng thái nhỏ thay cho biểu tượng cảm xúc */
.dot-ok, .dot-bad, .dot-warn, .dot-info { display: inline-block; width: 6px; height: 6px; border-radius: 1px; background: currentColor; flex: none; }

/* Khối */
.card { border: 1px solid var(--border); border-radius: var(--radius-lg); background: var(--surface); padding: 18px; }
.muted-sm { color: var(--fg-muted); font-size: .84rem; }
.empty { padding: 36px 16px; text-align: center; color: var(--fg-muted); border: 1px dashed var(--border); border-radius: var(--radius-lg); font-size: .9rem; }

/* Tabs */
.tabs { display: flex; gap: 18px; border-bottom: 1px solid var(--border); overflow-x: auto; scrollbar-width: none; }
.tabs [role="tab"] {
  position: relative; background: none; border: 0; margin-bottom: -1px; padding: 10px 0;
  color: var(--fg-muted); font-family: var(--font-ui); font-weight: 500; font-size: .875rem; cursor: pointer; white-space: nowrap;
  transition: color .15s;
}
.tabs [role="tab"]::after { content: ""; position: absolute; left: 0; right: 0; bottom: 0; height: 2px; background: var(--fg-deep); transform: scaleX(0); transform-origin: left; transition: transform .22s var(--ease); }
.tabs [role="tab"]:hover { color: var(--fg-deep); }
.tabs [role="tab"][aria-selected="true"] { color: var(--fg-deep); }
.tabs [role="tab"][aria-selected="true"]::after { transform: scaleX(1); }
.tab-count { margin-left: 5px; color: var(--fg-muted); font-size: .75rem; font-family: var(--font-mono); }

/* Bảng kiểu online judge: kẻ ngang mảnh, tiêu đề chữ nhỏ in hoa */
.table-wrap { overflow-x: auto; border-top: 1px solid var(--rule); border-bottom: 1px solid var(--border); }
.table { width: 100%; border-collapse: collapse; font-size: .9rem; }
.table th, .table td { padding: 10px 12px; text-align: left; border-bottom: 1px solid var(--border); vertical-align: middle; }
.table th { color: var(--fg-muted); font-weight: 500; font-size: .68rem; letter-spacing: .08em; text-transform: uppercase; white-space: nowrap; }
.table tr:last-child td { border-bottom: 0; }
.table tbody tr { transition: background-color .12s; }
.table tbody tr:hover { background: var(--surface-2); }
.table .num { text-align: right; font-family: var(--font-mono); font-size: .82rem; white-space: nowrap; }

/* Hộp thoại */
dialog.modal {
  width: min(640px, calc(100vw - 32px)); max-height: calc(100dvh - 32px); padding: 0;
  border: 1px solid var(--border); border-radius: var(--radius-lg); background: var(--bg); color: var(--fg); box-shadow: var(--shadow);
}
dialog.modal[open] { animation: dialog-in .2s var(--ease); }
dialog.modal::backdrop { background: rgba(10, 10, 10, .42); backdrop-filter: blur(2px); }
@keyframes dialog-in { from { opacity: 0; transform: translateY(8px) scale(.99); } }
.modal-head { display: flex; justify-content: space-between; align-items: center; gap: 12px; padding: 16px 20px; border-bottom: 1px solid var(--border); }
.modal-head h2 { margin: 0; font-size: 1.25rem; }
.modal-body { padding: 18px 20px; display: grid; gap: 14px; overflow-y: auto; }
.modal-foot { display: flex; justify-content: flex-end; flex-wrap: wrap; gap: 8px; padding: 12px 20px; border-top: 1px solid var(--border); }

/* Thông báo nhanh */
.toast-region { position: fixed; left: 50%; bottom: 24px; transform: translateX(-50%); z-index: 50; display: grid; gap: 8px; pointer-events: none; }
.toast { padding: 9px 16px; border-radius: var(--radius); background: var(--fg-deep); color: var(--bg); font-size: .875rem; box-shadow: var(--shadow); animation: toast-in .22s var(--ease); }
@keyframes toast-in { from { opacity: 0; transform: translateY(6px); } }

.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0; }

.boot-error { border: 1px solid var(--bad); border-left-width: 3px; color: var(--fg-deep); border-radius: var(--radius); padding: 14px 16px; }
.boot-error strong { color: var(--bad); }
.boot-error p { margin: 6px 0 0; font-size: .9rem; }

/* Thanh tài khoản */
.userbar { display: inline-flex; align-items: center; gap: 4px; flex-wrap: wrap; }
.prose .userbar-name { display: inline-flex; align-items: center; gap: 8px; border-bottom: 0; font-size: .875rem; color: var(--fg-deep); padding-right: 6px; }
.userbar-name .muted-sm { font-size: .78rem; font-family: var(--font-mono); }
.userbar-avatar { display: inline-grid; place-items: center; width: 24px; height: 24px; border-radius: 50%; border: 1px solid var(--fg-deep); color: var(--fg-deep); font-size: .7rem; font-weight: 600; }

/* Biểu mẫu & thông báo */
.auth-card { max-width: 420px; margin: 12px auto 0; display: grid; gap: 18px; }
.auth-card form { display: grid; gap: 14px; }
.form-error, .form-ok { border-left: 3px solid currentColor; padding: 6px 12px; font-size: .88rem; margin: 0; }
.form-error { color: var(--bad); background: var(--bad-bg); }
.form-ok { color: var(--ok); background: var(--ok-bg); }
.notice { border: 1px solid var(--border); border-left: 3px solid var(--fg-deep); border-radius: var(--radius); padding: 14px 18px; background: var(--surface); }
.notice h2 { margin: 0 0 6px; font-size: 1.2rem; }
.notice p { margin: 0 0 10px; }
.hp-field { position: absolute; left: -9999px; width: 1px; height: 1px; overflow: hidden; }

@media (max-width: 520px) {
  main.app-main { padding-top: 18px; }
  .table th, .table td { padding: 8px; }
  .tabs { gap: 14px; }
}
@media (prefers-reduced-motion: reduce) {
  main.app-main { transition: none; }
  .toast, dialog.modal[open], .swap-in { animation: none; }
  .tabs [role="tab"]::after { transition: none; }
}

/* ---------- Web app (PWA): nút cài đặt, báo ngoại tuyến, vùng an toàn trên điện thoại có tai thỏ ---------- */
.appbar-install {
  display: inline-flex; align-items: center; gap: 6px; height: 32px; padding: 0 12px; border-radius: 999px;
  border: 1px solid var(--accent, var(--fg-deep)); background: color-mix(in srgb, var(--accent, var(--fg-deep)) 10%, transparent);
  color: var(--fg-deep); font: inherit; font-size: .8rem; font-weight: 600; cursor: pointer; white-space: nowrap;
}
.appbar-install[hidden] { display: none; }
.appbar-install svg { width: 15px; height: 15px; }
.appbar-install:hover { background: color-mix(in srgb, var(--accent, var(--fg-deep)) 18%, transparent); }
.offline-banner {
  position: sticky; top: 0; z-index: 35; padding: 8px 16px; text-align: center; font-family: var(--font-ui); font-size: .84rem;
  background: color-mix(in srgb, var(--warn) 16%, var(--bg)); color: var(--fg-deep); border-bottom: 1px solid color-mix(in srgb, var(--warn) 40%, var(--border));
}
.offline-banner[hidden] { display: none; }
html.is-offline .appbar { top: 0; }
.install-steps { margin: 0 0 12px; padding-left: 1.3em; display: grid; gap: 6px; }
/* Khi chạy như ứng dụng (toàn màn hình), chừa chỗ cho tai thỏ / thanh trạng thái và thanh vuốt dưới đáy. */
.appbar { padding-top: env(safe-area-inset-top); }
.appbar-inner { padding-left: max(24px, env(safe-area-inset-left)); padding-right: max(24px, env(safe-area-inset-right)); }
html.is-standalone footer.app-footer { padding-bottom: max(48px, calc(env(safe-area-inset-bottom) + 24px)); }
html.is-standalone .appbar-nav a[href*="projects/"] { display: none; }
@media (display-mode: standalone) {
  body { overscroll-behavior-y: none; }
  .appbar-brand { pointer-events: auto; }
}
@media (max-width: 640px) {
  .appbar-inner { padding-left: max(16px, env(safe-area-inset-left)); padding-right: max(16px, env(safe-area-inset-right)); }
  .appbar-install span { display: none; }
  .appbar-install { width: 34px; padding: 0; justify-content: center; }
}