@import url('https://fonts.googleapis.com/css2?family=Outfit:wght@300;400;500;600;700;800;900&display=swap');

:root {
  --sidebar-w: 240px;
  --bg-primary:    #070c14;
  --bg-secondary:  #0d1526;
  --bg-card:       rgba(255,255,255,0.04);
  --bg-card-hover: rgba(255,255,255,0.07);
  --border:        rgba(255,255,255,0.08);
  --border-hover:  rgba(0,229,255,0.4);
  --accent:   #00e5ff;
  --accent-2: #00b4d8;
  --accent-3: #7c3aed;
  --success:  #00d68f;
  --danger:   #ff4d6d;
  --warning:  #ffb703;
  --text-primary:   #e8f4fd;
  --text-secondary: #7fa8c9;
  --text-muted:     #3a5470;
  --radius:    16px;
  --radius-sm: 10px;
  --shadow:    0 8px 32px rgba(0,0,0,0.6);
  --transition: 0.22s cubic-bezier(0.4,0,0.2,1);
  --glow-cyan: 0 0 18px rgba(0,229,255,0.3);
}

* { margin:0; padding:0; box-sizing:border-box; }
html { scroll-behavior:smooth; }

body {
  font-family: 'Outfit', 'Inter', sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  overflow-x: hidden;
  display: flex;
}

body::before {
  content:''; position:fixed; inset:0;
  background:
    radial-gradient(ellipse 55% 45% at 5% 0%, rgba(0,180,216,0.07) 0%, transparent 60%),
    radial-gradient(ellipse 45% 40% at 95% 100%, rgba(124,58,237,0.06) 0%, transparent 60%);
  pointer-events:none; z-index:0;
}

/* ===========================
   SIDEBAR
   =========================== */
.sidebar {
  position: fixed;
  top: 0; left: 0;
  width: var(--sidebar-w);
  height: 100vh;
  background: rgba(10,16,30,0.92);
  border-right: 1px solid rgba(0,229,255,0.08);
  backdrop-filter: blur(24px);
  display: flex;
  flex-direction: column;
  padding: 20px 12px;
  z-index: 1000;
  overflow-y: auto;
  overflow-x: hidden;
  transition: transform 0.3s cubic-bezier(0.4,0,0.2,1);
}

.sidebar::-webkit-scrollbar { width:0; }

/* Logo */
.sidebar-brand { padding: 4px 6px 20px; border-bottom: 1px solid rgba(0,229,255,0.07); margin-bottom: 16px; }
.sidebar-logo { display:flex; align-items:center; gap:12px; }
.sidebar-logo-icon {
  width: 40px; height: 40px;
  background: linear-gradient(135deg, #00b4d8, #7c3aed);
  border-radius: 12px;
  display: flex; align-items:center; justify-content:center;
  font-size: 1.2rem; font-weight: 900; color: #fff;
  box-shadow: var(--glow-cyan);
  flex-shrink: 0;
}
.sidebar-logo-name { display:block; font-size:1rem; font-weight:800; color:var(--text-primary); letter-spacing:-0.02em; }
.sidebar-logo-sub  { display:block; font-size:0.65rem; font-weight:500; color:var(--text-muted); letter-spacing:0.04em; margin-top:1px; }

/* Section labels */
.sidebar-section-label {
  font-size: 0.62rem; font-weight:700; letter-spacing:0.12em;
  color: var(--text-muted); padding: 0 10px; margin-bottom: 6px;
}

/* Nav links */
.sidebar-nav { display:flex; flex-direction:column; gap:2px; margin-bottom:8px; }

.sidebar-link {
  display: flex; align-items:center; gap:12px;
  padding: 11px 12px;
  border-radius: 12px;
  text-decoration: none;
  color: var(--text-secondary);
  font-size: 0.88rem; font-weight:500;
  transition: var(--transition);
  position: relative;
  white-space: nowrap;
  overflow: hidden;
  border: 1px solid transparent;
}

.sidebar-link:hover {
  color: var(--text-primary);
  background: rgba(255,255,255,0.05);
  border-color: rgba(255,255,255,0.06);
}

.sidebar-link.active {
  color: var(--accent);
  background: rgba(0,229,255,0.08);
  border-color: rgba(0,229,255,0.18);
  font-weight: 600;
}

.sidebar-link.active::before {
  content: '';
  position: absolute;
  left: 0; top: 20%; bottom: 20%;
  width: 3px;
  background: var(--accent);
  border-radius: 0 3px 3px 0;
  box-shadow: 0 0 10px var(--accent);
}

.sidebar-link-icon {
  width: 32px; height: 32px;
  display: flex; align-items:center; justify-content:center;
  border-radius: 9px;
  background: rgba(255,255,255,0.05);
  flex-shrink: 0;
  transition: var(--transition);
}
.sidebar-link-icon .material-icons { font-size: 18px; }

.sidebar-link.active .sidebar-link-icon {
  background: rgba(0,229,255,0.12);
  color: var(--accent);
  box-shadow: 0 0 12px rgba(0,229,255,0.2);
}

.sidebar-link-text { flex: 1; }

.sidebar-link-badge {
  font-size: 0.65rem; font-weight:700;
  background: var(--accent); color: #070c14;
  border-radius: 20px; padding: 1px 6px;
  display: none;
}
.sidebar-link-badge:not(:empty) { display:inline; }

/* Vocabulary tools hub */
.vocab-tools-shell { max-width:1380px; }
.vocab-tools-header { display:flex; align-items:flex-end; justify-content:space-between; gap:24px; margin-bottom:20px; padding:25px 27px; border:1px solid var(--border); border-radius:16px; background:linear-gradient(125deg,rgba(0,229,255,.055),rgba(124,58,237,.04)); }
.vocab-tools-kicker { display:block; margin-bottom:5px; color:var(--warning); font-size:.65rem; font-weight:850; letter-spacing:.12em; }
.vocab-tools-header h1 { color:var(--text-primary); font-size:clamp(1.6rem,2.4vw,2.2rem); letter-spacing:-.035em; }
.vocab-tools-header p { max-width:720px; margin-top:7px; color:var(--text-secondary); font-size:.86rem; line-height:1.55; }
.vocab-tools-total { flex:none; min-width:135px; padding:12px 15px; border:1px solid var(--border); border-radius:11px; background:rgba(255,255,255,.025); text-align:right; }
.vocab-tools-total b,.vocab-tools-total span { display:block; }
.vocab-tools-total b { color:var(--accent); font-size:1.35rem; }
.vocab-tools-total span { margin-top:2px; color:var(--text-muted); font-size:.68rem; }
.vocab-tools-grid { display:grid; grid-template-columns:repeat(2,minmax(0,1fr)); gap:12px; }
.vocab-topic-card { display:grid; grid-template-columns:minmax(230px,1fr) minmax(130px,170px); align-items:center; gap:15px; min-height:190px; padding:16px 17px; border:1px solid var(--border); border-radius:14px; color:var(--text-primary); background:linear-gradient(105deg,rgba(28,36,34,.98),rgba(23,30,31,.98)); box-shadow:0 5px 16px rgba(0,0,0,.1); }
.vocab-topic-card.recommended { border-color:rgba(226,184,88,.58); background:linear-gradient(105deg,rgba(48,43,30,.98),rgba(27,35,33,.98)); }
.vocab-topic-main { display:grid; grid-template-columns:48px minmax(0,1fr); align-items:center; gap:14px; min-width:0; padding:0; border:0; color:inherit; background:transparent; text-align:left; cursor:pointer; font:inherit; }
.vocab-topic-number { display:grid; place-items:center; width:46px; height:46px; border:1px solid rgba(213,174,82,.2); border-radius:11px; color:var(--warning); background:rgba(213,174,82,.08); font-size:.9rem; font-weight:850; }
.vocab-topic-copy { min-width:0; }
.vocab-topic-copy>span { display:flex; align-items:center; gap:7px; flex-wrap:wrap; }
.vocab-topic-copy b { color:var(--text-primary); font-size:1.02rem; }
.vocab-topic-copy em { padding:3px 7px; border-radius:99px; color:var(--warning); background:rgba(213,174,82,.1); font-size:.54rem; font-style:normal; font-weight:800; letter-spacing:.06em; }
.vocab-topic-copy small { display:block; margin-top:4px; color:var(--text-secondary); font-size:.7rem; }
.vocab-topic-copy p { overflow:hidden; margin-top:7px; color:var(--text-muted); font-size:.67rem; line-height:1.4; text-overflow:ellipsis; white-space:nowrap; }
.vocab-topic-progress i { display:block; height:7px; overflow:hidden; border:1px solid rgba(213,174,82,.09); border-radius:9px; background:rgba(255,255,255,.055); }
.vocab-topic-progress i em { display:block; height:100%; background:linear-gradient(90deg,#9f7835,#d1a94f); }
.vocab-topic-progress>span { display:flex; justify-content:space-between; gap:6px; margin-top:7px; font-size:.62rem; }
.vocab-topic-progress b { color:var(--warning); }.vocab-topic-progress small { color:var(--text-muted); }
.vocab-topic-actions { grid-column:1/3; display:flex; flex-direction:column; gap:8px; }
.vocab-topic-options { display:grid; grid-template-columns:minmax(0,1fr) 170px; gap:7px; }
.vocab-topic-practice { display:grid; grid-template-columns:repeat(3,minmax(0,1fr)); gap:7px; }
.vocab-topic-actions button,.vocab-topic-actions label { min-height:42px; border:1px solid var(--border); border-radius:8px; color:var(--text-secondary); background:rgba(10,15,14,.58); }
.vocab-topic-actions button { display:flex; align-items:center; justify-content:center; gap:6px; padding:8px 10px; cursor:pointer; font:inherit; }
.vocab-topic-actions button:hover { color:var(--text-primary); border-color:var(--border-hover); }
.vocab-topic-actions .material-icons { font-size:17px; }.vocab-topic-actions button b { font-size:.74rem; white-space:nowrap; }
.vocab-topic-options .vocab-topic-view { justify-content:flex-start; padding-inline:13px; }
.vocab-topic-options label { display:flex; align-items:center; justify-content:space-between; gap:8px; padding:5px 7px 5px 11px; }
.vocab-topic-options label>span { color:var(--text-muted); font-size:.62rem; font-weight:800; white-space:nowrap; }
.vocab-topic-count-label i { display:none; font-style:normal; }
.vocab-topic-actions select { width:auto; min-width:78px; min-height:32px; padding:2px 24px 2px 7px; border:0; color:var(--text-primary); background:transparent; font-size:.69rem; }
.vocab-topic-practice button { min-height:48px; }
.vocab-topic-listen { color:#9bd6ee!important; border-color:rgba(71,157,195,.46)!important; background:rgba(45,126,161,.12)!important; }
.vocab-topic-write { color:#bce7ce!important; border-color:rgba(75,115,94,.5)!important; background:rgba(75,115,94,.13)!important; }
.vocab-topic-quiz { color:var(--warning)!important; border-color:rgba(213,174,82,.42)!important; background:rgba(213,174,82,.07)!important; }

@media (max-width:1250px) {
  .vocab-tools-grid { grid-template-columns:1fr; }
}
@media (max-width:680px) {
  .vocab-tools-header { align-items:flex-start; flex-direction:column; padding:20px; }
  .vocab-tools-total { width:100%; text-align:left; }
  .vocab-tools-grid { grid-template-columns:1fr; }
  .vocab-topic-card { grid-template-columns:1fr; padding:14px; }
  .vocab-topic-progress,.vocab-topic-actions { grid-column:1; }
  .vocab-topic-options { grid-template-columns:minmax(0,1fr) 145px; gap:6px; }
  .vocab-topic-practice { gap:6px; }
  .vocab-topic-actions button { gap:4px; padding:7px 5px; }
  .vocab-topic-actions button b { font-size:.65rem; }
  .vocab-topic-options label { gap:4px; padding:4px 5px 4px 7px; }
  .vocab-topic-options label>span { font-size:.52rem; }
  .vocab-topic-count-label>span { display:none; }
  .vocab-topic-count-label i { display:inline; }
  .vocab-topic-actions select { width:76px; min-width:0; padding-right:20px; font-size:.63rem; }
}

/* Footer stats */
.sidebar-footer {
  padding: 16px 6px 4px;
  border-top: 1px solid rgba(0,229,255,0.07);
  display: flex; flex-direction:column; gap:10px;
}
.sidebar-stat {
  display: flex; align-items:center; gap:10px;
  padding: 8px 10px;
  background: rgba(255,255,255,0.03);
  border-radius: 10px;
  border: 1px solid rgba(255,255,255,0.05);
}
.sidebar-stat-value { font-size:1rem; font-weight:800; color:var(--text-primary); line-height:1; }
.sidebar-stat-label { font-size:0.65rem; color:var(--text-muted); margin-top:2px; }

.account-badge {
  width:100%; display:flex; align-items:center; justify-content:center; gap:6px;
  padding:8px; border-radius:10px; border:1px solid rgba(0,229,255,.18);
  background:rgba(0,229,255,.06); color:var(--text-secondary); cursor:pointer;
  font:500 .7rem inherit; overflow:hidden;
}
.account-badge span:last-child { overflow:hidden; text-overflow:ellipsis; white-space:nowrap; }
.account-badge .material-icons { font-size:16px; flex:none; }
.account-badge.signed-in { color:var(--success); border-color:rgba(0,214,143,.25); background:rgba(0,214,143,.07); }
.account-modal { position:fixed; inset:0; z-index:3000; display:grid; place-items:center; padding:20px; background:rgba(2,6,14,.78); backdrop-filter:blur(8px); }
.account-modal[hidden] { display:none; }
.account-dialog { position:relative; width:min(520px,100%); max-height:min(760px,calc(100vh - 40px)); overflow:auto; padding:28px; border:1px solid rgba(0,229,255,.2); border-radius:18px; background:#0d1526; box-shadow:0 24px 80px rgba(0,0,0,.65); }
.account-dialog h2 { margin-bottom:8px; }
.account-dialog p { color:var(--text-secondary); font-size:.9rem; margin-bottom:20px; }
.account-dialog form { display:grid; gap:14px; }
.account-dialog label { display:grid; gap:6px; color:var(--text-secondary); font-size:.8rem; }
.account-dialog input { width:100%; padding:11px 12px; border:1px solid var(--border); border-radius:10px; background:rgba(255,255,255,.05); color:var(--text-primary); font:inherit; }
.account-dialog input:focus { outline:none; border-color:var(--accent); }
.account-close { position:absolute; top:12px; right:14px; border:0; background:transparent; color:var(--text-secondary); font-size:1.7rem; cursor:pointer; }
.account-error { padding:9px 11px; border-radius:9px; color:#ffd9e0; background:rgba(255,77,109,.13); font-size:.8rem; }
.account-success { margin-top:12px; padding:9px 11px; border-radius:9px; color:#bdfbe2; background:rgba(0,214,143,.12); font-size:.8rem; }
.account-service-status { margin:-8px 0 16px; padding:9px 11px; border-radius:9px; color:var(--success); background:rgba(0,214,143,.08); font-size:.78rem; }
.account-service-status.unavailable { color:var(--warning); background:rgba(255,183,3,.09); }
.account-dialog button:disabled { opacity:.45; cursor:not-allowed; transform:none; }
.account-sync-conflict { margin-top:16px; padding:14px; border:1px solid rgba(255,183,3,.25); border-radius:10px; background:rgba(255,183,3,.06); }
.account-sync-conflict p { margin:5px 0 12px; }
.account-sync-conflict > div { display:flex; gap:8px; flex-wrap:wrap; }
.account-tabs { display:flex; gap:6px; padding:4px; margin-bottom:16px; border-radius:10px; background:rgba(255,255,255,.04); }
.account-tabs button { flex:1; padding:8px; border:0; border-radius:7px; color:var(--text-secondary); background:transparent; cursor:pointer; }
.account-tabs button.active { color:var(--text-primary); background:rgba(0,229,255,.12); }
.account-check { grid-template-columns:auto 1fr!important; align-items:start; }
.account-check input { width:auto; margin-top:3px; }
.account-link-button { border:0; color:var(--accent); background:transparent; cursor:pointer; }
.account-subscription { margin:12px 0 18px; padding:12px; border:1px solid rgba(0,229,255,.2); border-radius:10px; color:var(--text-secondary); }
.account-terms-update { margin:12px 0; padding:12px; border:1px solid rgba(255,183,3,.3); border-radius:10px; background:rgba(255,183,3,.06); }
.account-orders-wrap { margin:0 0 18px; }
.account-preference { margin-bottom:16px; }
.account-orders-wrap h3 { margin-bottom:8px; font-size:.95rem; }
.account-orders { display:grid; gap:8px; color:var(--text-secondary); font-size:.8rem; }
.account-order { display:grid; gap:3px; padding:9px 10px; border-radius:8px; background:rgba(255,255,255,.035); }
.account-actions { display:flex; flex-wrap:wrap; gap:8px; }
.account-security-form,.account-danger-zone form { display:grid; gap:12px; margin-top:16px; }
.account-danger-zone { margin-top:22px; color:var(--danger); }
.account-danger-zone summary { cursor:pointer; }
.pricing-page { max-width:980px; }
.pricing-grid { display:grid; grid-template-columns:repeat(auto-fit,minmax(260px,1fr)); gap:18px; margin:28px 0; }
.pricing-card { padding:26px; border:1px solid var(--border); border-radius:18px; background:var(--bg-card); }
.pricing-card.featured { border-color:rgba(0,229,255,.45); box-shadow:0 14px 50px rgba(0,180,216,.12); }
.pricing-price { margin:12px 0 20px; color:var(--accent); font-size:2rem; font-weight:800; }
.pricing-card ul { display:grid; gap:10px; margin:0 0 24px; padding:0; list-style:none; color:var(--text-secondary); }
.pricing-card li { display:flex; align-items:center; gap:8px; }
.pricing-card li .material-icons { color:var(--success); font-size:18px; }
.pricing-note { padding:20px; border-radius:14px; background:rgba(255,255,255,.035); color:var(--text-secondary); }
.pricing-note p { margin:8px 0 0; }
.invoice-request { margin:0 0 18px; padding:16px; border:1px solid var(--border); border-radius:12px; }
.invoice-request summary { cursor:pointer; color:var(--accent); }
.invoice-fields { display:grid; grid-template-columns:repeat(auto-fit,minmax(210px,1fr)); gap:12px; margin-top:14px; }
.invoice-fields label { display:grid; gap:6px; color:var(--text-secondary); font-size:.82rem; }
.invoice-fields input { padding:10px; border:1px solid var(--border); border-radius:8px; background:rgba(255,255,255,.05); color:var(--text-primary); }
.public-footer { position:relative; z-index:2; display:flex; justify-content:center; align-items:center; flex-wrap:wrap; gap:18px; padding:18px 24px 28px; color:var(--text-muted); font-size:.76rem; }
.public-footer span { flex-basis:100%; text-align:center; }
.public-footer a { color:var(--text-secondary); text-decoration:none; }
.public-footer a:hover { color:var(--accent); }

/* Mobile toggle */
.sidebar-toggle {
  display: none;
  position: fixed; top:14px; left:14px; z-index:1100;
  width:40px; height:40px; border-radius:10px;
  background: rgba(13,21,38,0.95);
  border: 1px solid rgba(0,229,255,0.2);
  color: var(--accent);
  cursor:pointer; align-items:center; justify-content:center;
  backdrop-filter: blur(12px);
}

/* ===========================
   MAIN WRAPPER
   =========================== */
.main-wrapper {
  margin-left: var(--sidebar-w);
  min-height: 100vh;
  width: calc(100% - var(--sidebar-w));
  position: relative;
  z-index: 1;
}

/* ===========================
   PAGE
   =========================== */
.page {
  display: none;
  min-height: 100vh;
  padding: 36px 36px 60px;
}
.page.active { display: block; animation: pageIn 0.28s ease; }
@keyframes pageIn { from{opacity:0;transform:translateY(8px);} to{opacity:1;transform:translateY(0);} }

.container { max-width: 1080px; margin: 0 auto; }

/* ===========================
   CARDS
   =========================== */
.card {
  background: rgba(13,21,38,0.75);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  backdrop-filter: blur(14px);
  transition: var(--transition);
}
.card:hover { border-color: rgba(0,229,255,0.16); }

/* ===========================
   HEADINGS
   =========================== */
.page-title {
  font-size: 1.75rem; font-weight:800; margin-bottom:4px;
  background: linear-gradient(135deg, #e8f4fd 40%, var(--accent));
  -webkit-background-clip:text; -webkit-text-fill-color:transparent; background-clip:text;
}
.page-sub { color:var(--text-secondary); font-size:0.88rem; margin-bottom:26px; }
.section-title { font-size:0.95rem; font-weight:700; color:var(--text-primary); margin-bottom:14px; display:flex; align-items:center; gap:8px; }

/* ===========================
   BUTTONS
   =========================== */
.btn {
  display:inline-flex; align-items:center; gap:6px;
  padding:9px 16px; border-radius:var(--radius-sm);
  border:1px solid var(--border);
  background:rgba(255,255,255,0.04);
  color:var(--text-primary);
  font-family:inherit; font-size:0.85rem; font-weight:500;
  cursor:pointer; transition:var(--transition); white-space:nowrap;
}
.btn:hover { background:rgba(255,255,255,0.07); border-color:rgba(0,229,255,0.3); transform:translateY(-1px); }

.btn-primary {
  background: linear-gradient(135deg, #005fa3, #7c3aed);
  border-color:transparent; color:#fff;
  box-shadow: 0 4px 14px rgba(0,95,163,0.4);
}
.btn-primary:hover { transform:translateY(-2px); box-shadow: 0 6px 20px rgba(0,95,163,0.55); }

.btn-success {
  background: linear-gradient(135deg, var(--success), #009966);
  border-color:transparent; color:#fff;
  box-shadow: 0 4px 14px rgba(0,214,143,0.3);
}
.btn-danger {
  background:transparent; border-color:rgba(255,77,109,0.3);
  color:var(--danger); font-size:0.8rem; padding:6px 12px;
}
.btn-danger:hover { background:rgba(255,77,109,0.1); border-color:var(--danger); transform:none; }
.btn-sm { padding:6px 11px; font-size:0.78rem; }

/* ===========================
   FORMS
   =========================== */
.form-group { margin-bottom:15px; }
label {
  display:block; font-size:0.72rem; font-weight:700;
  color:var(--text-secondary); margin-bottom:5px;
  text-transform:uppercase; letter-spacing:0.06em;
}
input[type="text"], input[type="number"], input[type="date"], textarea, select {
  width:100%; padding:10px 13px;
  background:rgba(255,255,255,0.04);
  border:1px solid var(--border);
  border-radius:var(--radius-sm);
  color:var(--text-primary); font-family:inherit; font-size:0.88rem;
  transition:var(--transition); outline:none;
}
input:focus, textarea:focus, select:focus {
  border-color:var(--accent);
  background:rgba(0,229,255,0.04);
  box-shadow: 0 0 0 3px rgba(0,229,255,0.1);
}
input::placeholder, textarea::placeholder { color:var(--text-muted); }
textarea { resize:vertical; min-height:80px; }
select option { background:var(--bg-secondary); }

/* ===========================
   GRID
   =========================== */
.grid-2 { display:grid; grid-template-columns:1fr 1fr; gap:18px; }
.grid-3 { display:grid; grid-template-columns:repeat(3,1fr); gap:14px; }
.grid-4 { display:grid; grid-template-columns:repeat(4,1fr); gap:14px; }
.grid-5 { display:grid; grid-template-columns:repeat(5,1fr); gap:14px; }

/* ===========================
   TABLE
   =========================== */
.table-wrapper { overflow-x:auto; border-radius:var(--radius-sm); }
table { width:100%; border-collapse:collapse; }
thead th {
  padding:11px 15px; background:rgba(0,229,255,0.04);
  color:var(--text-secondary); font-size:0.7rem; font-weight:700;
  text-transform:uppercase; letter-spacing:0.07em;
  text-align:left; border-bottom:1px solid var(--border);
}
tbody tr { border-bottom:1px solid rgba(255,255,255,0.03); transition:var(--transition); }
tbody tr:hover { background:rgba(0,229,255,0.03); }
tbody td { padding:11px 15px; font-size:0.85rem; color:var(--text-primary); vertical-align:middle; }
.word-cell { font-weight:700; color:var(--accent); }
.pos-badge {
  display:inline-flex; padding:2px 8px; border-radius:20px;
  font-size:0.7rem; font-weight:700;
  background:rgba(0,229,255,0.1); color:var(--accent);
  border:1px solid rgba(0,229,255,0.2);
}

/* ===========================
   FLASHCARD
   =========================== */
.flashcard-scene { perspective:1200px; width:100%; max-width:480px; height:260px; margin:0 auto 24px; cursor:pointer; }
.flashcard { width:100%; height:100%; position:relative; transform-style:preserve-3d; transition:transform 0.6s cubic-bezier(0.4,0,0.2,1); }
.flashcard.flipped { transform:rotateY(180deg); }
.flashcard-face { position:absolute; inset:0; backface-visibility:hidden; border-radius:20px; display:flex; flex-direction:column; align-items:center; justify-content:center; padding:32px; text-align:center; border:1px solid var(--border); }
.flashcard-front { background:linear-gradient(135deg,rgba(0,119,182,0.18),rgba(0,180,216,0.1)); border-color:rgba(0,229,255,0.25); }
.flashcard-back  { background:linear-gradient(135deg,rgba(0,214,143,0.15),rgba(0,180,216,0.1)); border-color:rgba(0,214,143,0.3); transform:rotateY(180deg); }
.card-word    { font-size:2rem; font-weight:800; color:var(--text-primary); margin-bottom:8px; }
.card-phonetic{ font-size:0.95rem; color:var(--accent); margin-bottom:12px; }
.card-label   { font-size:0.72rem; color:var(--text-muted); text-transform:uppercase; letter-spacing:0.08em; margin-bottom:8px; }
.card-meaning { font-size:1.3rem; font-weight:600; color:var(--text-primary); margin-bottom:8px; }
.card-example { font-size:0.8rem; color:var(--text-secondary); font-style:italic; }
.fc-controls  { display:flex; align-items:center; justify-content:center; gap:12px; flex-wrap:wrap; }
.fc-counter   { font-size:0.85rem; color:var(--text-secondary); font-weight:600; min-width:80px; text-align:center; }

.progress-bar-wrap { background:rgba(255,255,255,0.06); border-radius:10px; height:5px; margin:14px 0; overflow:hidden; }
.progress-bar { height:100%; background:linear-gradient(90deg,var(--accent),var(--accent-3)); border-radius:10px; transition:width 0.5s ease; }

/* ===========================
   QUIZ
   =========================== */
.quiz-question { font-size:1.3rem; font-weight:700; text-align:center; color:var(--text-primary); margin-bottom:24px; padding:18px; background:rgba(0,229,255,0.06); border-radius:var(--radius); border:1px solid rgba(0,229,255,0.15); }
.quiz-options { display:grid; grid-template-columns:1fr 1fr; gap:10px; }
.quiz-option { padding:13px 16px; background:rgba(255,255,255,0.04); border:2px solid var(--border); border-radius:var(--radius-sm); color:var(--text-primary); font-family:inherit; font-size:0.88rem; font-weight:500; cursor:pointer; transition:var(--transition); text-align:left; }
.quiz-option:hover:not(:disabled) { background:rgba(0,229,255,0.08); border-color:var(--accent); transform:translateY(-1px); }
.quiz-option.correct { background:rgba(0,214,143,0.12); border-color:var(--success); color:var(--success); }
.quiz-option.wrong   { background:rgba(255,77,109,0.1); border-color:var(--danger); color:var(--danger); }
.quiz-option:disabled { cursor:not-allowed; transform:none; }
.quiz-result-icon { font-size:3rem; margin-bottom:12px; }
.score-circle { width:120px; height:120px; border-radius:50%; background:conic-gradient(var(--accent) var(--pct,0%),rgba(255,255,255,0.06) 0); display:flex; align-items:center; justify-content:center; font-size:1.5rem; font-weight:800; margin:0 auto 20px; position:relative; }
.score-circle::before { content:''; position:absolute; inset:10px; background:var(--bg-secondary); border-radius:50%; }
.score-circle span { position:relative; z-index:1; }

/* ===========================
   WRITING
   =========================== */
.writing-hint  { text-align:center; font-size:0.85rem; color:var(--text-secondary); margin-bottom:20px; }
.writing-input { font-size:1.1rem; text-align:center; font-weight:600; letter-spacing:0.04em; }
.hint-letters  { display:flex; justify-content:center; gap:6px; margin-bottom:16px; flex-wrap:wrap; }
.hint-letter   { width:36px; height:40px; border-bottom:2px solid var(--accent); display:flex; align-items:center; justify-content:center; font-size:1rem; font-weight:700; color:var(--text-primary); }
.feedback-correct { color:var(--success); font-weight:600; font-size:0.9rem; text-align:center; }
.feedback-wrong   { color:var(--danger);  font-weight:600; font-size:0.9rem; text-align:center; }

/* ===========================
   SRS REVIEW
   =========================== */
.srs-rating-grid { display:grid; grid-template-columns:repeat(4,1fr); gap:10px; margin-top:20px; }
.srs-rate-btn {
  display:flex; flex-direction:column; align-items:center; gap:4px;
  padding:12px 8px; border-radius:var(--radius-sm); border:2px solid var(--border);
  background:rgba(255,255,255,0.03); color:var(--text-primary);
  font-family:inherit; font-weight:700; font-size:0.9rem; cursor:pointer;
  transition:var(--transition);
}
.srs-rate-btn span { font-size:0.68rem; font-weight:500; color:var(--text-muted); }
.srs-rate-btn:hover { transform:translateY(-2px); }
.srs-rate-again { border-color:rgba(255,77,109,0.4); }
.srs-rate-again:hover { background:rgba(255,77,109,0.12); border-color:var(--danger); }
.srs-rate-hard  { border-color:rgba(255,183,3,0.4); }
.srs-rate-hard:hover  { background:rgba(255,183,3,0.12); border-color:var(--warning); }
.srs-rate-good  { border-color:rgba(0,229,255,0.4); }
.srs-rate-good:hover  { background:rgba(0,229,255,0.12); border-color:var(--accent); }
.srs-rate-easy  { border-color:rgba(0,214,143,0.4); }
.srs-rate-easy:hover  { background:rgba(0,214,143,0.12); border-color:var(--success); }

/* ===========================
   LISTENING (NGHE - ĐIỀN TỪ)
   =========================== */
.lst-play-btn {
  width:76px; height:76px; border-radius:50%;
  background:linear-gradient(135deg, var(--accent), var(--accent-3));
  border:none; color:#fff; cursor:pointer;
  display:inline-flex; align-items:center; justify-content:center;
  box-shadow:var(--glow-cyan); transition:var(--transition);
}
.lst-play-btn .material-icons { font-size:34px; }
.lst-session-topic { margin:-2px 0 14px; padding:8px 12px; border:1px solid var(--border); border-radius:8px; color:var(--accent); background:rgba(0,229,255,.045); text-align:center; font-size:.78rem; font-weight:750; }
.lst-play-btn:hover { transform:scale(1.08); }
.lst-play-btn:active { transform:scale(0.96); }

/* ===========================
   STAT CARDS (Dashboard)
   =========================== */
.stat-card {
  background: rgba(13,21,38,0.85);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px 20px;
  position:relative; overflow:hidden; transition:var(--transition);
}
.stat-card::before {
  content:''; position:absolute; top:0; left:0; right:0; height:3px;
  background: var(--accent-color, var(--accent));
  box-shadow: 0 0 12px var(--accent-color, var(--accent));
}
.stat-card:hover { transform:translateY(-4px); box-shadow:var(--shadow); border-color:rgba(0,229,255,0.14); }
.stat-card .icon  { font-size:1.8rem; margin-bottom:12px; }
.stat-card .value { font-size:2.2rem; font-weight:900; color:var(--text-primary); line-height:1; }
.stat-card .label { font-size:0.78rem; color:var(--text-secondary); font-weight:500; margin-top:6px; }

/* ===========================
   TOPIC TAGS
   =========================== */
.topic-tag { display:inline-flex; align-items:center; gap:4px; padding:4px 10px; border-radius:20px; font-size:0.73rem; font-weight:600; border:1px solid var(--border); background:rgba(255,255,255,0.04); color:var(--text-secondary); cursor:pointer; transition:var(--transition); }
.topic-tag:hover, .topic-tag.active { background:rgba(0,229,255,0.1); border-color:rgba(0,229,255,0.35); color:var(--accent); }

/* ===========================
   SEARCH
   =========================== */
.search-wrap { position:relative; margin-bottom:14px; }
.search-wrap input { padding-left:38px; }
.search-icon { position:absolute; left:12px; top:50%; transform:translateY(-50%); color:var(--text-muted); font-size:0.9rem; }

/* ===========================
   EMPTY STATE
   =========================== */
.empty-state { text-align:center; padding:60px 20px; color:var(--text-muted); }
.empty-state .icon { font-size:3rem; margin-bottom:12px; }
.empty-state p { font-size:0.9rem; }

/* ===========================
   TOAST
   =========================== */
.toast-container { position:fixed; bottom:24px; right:24px; z-index:9999; display:flex; flex-direction:column; gap:8px; }
.toast { padding:11px 16px; border-radius:var(--radius-sm); font-size:0.85rem; font-weight:500; color:#fff; animation:slideIn 0.3s ease; max-width:300px; box-shadow:var(--shadow); }
.toast.success { background:linear-gradient(135deg,var(--success),#009966); }
.toast.error   { background:linear-gradient(135deg,var(--danger),#cc0033); }
.toast.info    { background:linear-gradient(135deg,#005fa3,var(--accent-3)); }
@keyframes slideIn { from{transform:translateX(100%);opacity:0;} to{transform:translateX(0);opacity:1;} }

/* ===========================
   MODAL
   =========================== */
.modal-overlay { display:none; position:fixed; inset:0; background:rgba(0,0,0,0.75); backdrop-filter:blur(8px); z-index:2000; align-items:center; justify-content:center; }
.modal-overlay.open { display:flex; }
.modal { background:var(--bg-secondary); border:1px solid rgba(0,229,255,0.15); border-radius:20px; padding:26px; width:100%; max-width:500px; animation:popIn 0.25s cubic-bezier(0.34,1.56,0.64,1); max-height:90vh; overflow-y:auto; }
@keyframes popIn { from{transform:scale(0.85);opacity:0;} to{transform:scale(1);opacity:1;} }
.modal-header { display:flex; align-items:center; justify-content:space-between; margin-bottom:18px; }
.modal-title { font-size:1.05rem; font-weight:700; }
.modal-close { width:30px; height:30px; border:none; background:rgba(255,255,255,0.06); border-radius:8px; color:var(--text-secondary); cursor:pointer; display:flex; align-items:center; justify-content:center; transition:var(--transition); }
.modal-close:hover { background:rgba(255,77,109,0.15); color:var(--danger); }

/* ===========================
   STREAK CALENDAR
   =========================== */
.streak-grid { display:grid; grid-template-columns:repeat(7,1fr); gap:4px; }
.streak-day { aspect-ratio:1; border-radius:5px; background:rgba(255,255,255,0.04); }
.streak-day.done  { background:var(--accent); box-shadow:0 0 8px rgba(0,229,255,0.4); }
.streak-day.today { outline:2px solid var(--accent-3); }

/* ===========================
   STARS
   =========================== */
.stars { display:flex; gap:4px; }
.star { font-size:1rem; cursor:pointer; color:var(--text-muted); transition:color 0.15s; }
.star.on { color:var(--warning); }

/* ===========================
   FILE SYNC
   =========================== */
.file-sync-badge { display:inline-flex; align-items:center; gap:4px; font-size:0.72rem; font-weight:600; padding:4px 10px; border-radius:20px; border:1px solid; cursor:default; transition:all 0.3s ease; white-space:nowrap; }
.file-sync-badge.inactive { background:rgba(255,255,255,0.05); border-color:rgba(255,255,255,0.1); color:var(--text-muted); }
.file-sync-badge.active   { background:rgba(0,214,143,0.12); border-color:rgba(0,214,143,0.4); color:var(--success); }
.file-sync-badge.error    { background:rgba(255,77,109,0.12); border-color:rgba(255,77,109,0.4); color:var(--danger); }

/* ===========================
   SCROLLBAR
   =========================== */
::-webkit-scrollbar { width:5px; }
::-webkit-scrollbar-track { background:transparent; }
::-webkit-scrollbar-thumb { background:rgba(0,229,255,0.15); border-radius:3px; }
::-webkit-scrollbar-thumb:hover { background:rgba(0,229,255,0.3); }

/* ===========================
   FLASHCARD GRID
   =========================== */
.fc-grid { display:grid; grid-template-columns:repeat(auto-fill,minmax(220px,1fr)); gap:18px; width:100%; }
.fc-grid .flashcard-scene { max-width:100%; height:220px; margin:0; }
.fc-grid .card-word    { font-size:1.5rem; }
.fc-grid .card-meaning { font-size:1.1rem; }

/* ===========================
   RESPONSIVE
   =========================== */
@media (max-width: 900px) {
  :root { --sidebar-w: 0px; }

  .sidebar {
    width: 240px;
    transform: translateX(-100%);
  }
  .sidebar.open {
    transform: translateX(0);
    box-shadow: 4px 0 40px rgba(0,0,0,0.6);
  }

  .sidebar-toggle { display:flex; }

  .main-wrapper {
    margin-left: 0;
    width: 100%;
  }

  .page { padding: 60px 16px 40px; }

  .grid-2, .grid-4 { grid-template-columns:1fr; }
  .grid-3, .grid-5 { grid-template-columns:1fr 1fr; }
  .quiz-options { grid-template-columns:1fr; }
  .srs-rating-grid { grid-template-columns:1fr 1fr; }
}