/* ========================================================================
   Advanced ITT MCQ Practice Bank — Premium Study Theme
   ======================================================================== */

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

/* === TOKENS (Default / Dark Mode) === */
:root {
  --bg:          #080c14;
  --bg-raised:   #0f172a;
  --bg-card:     #131e35;
  --bg-card-h:   #1e2942;
  --bg-input:    #182235;
  --bg-sidebar:  #0a1120;

  --text:        #f8fafc;
  --text-2:      #cbd5e1;
  --text-3:      #64748b;

  --accent:      #6366f1;
  --accent-l:    #818cf8;
  --accent-glow: rgba(99,102,241,0.15);
  --grad:        linear-gradient(135deg, #6366f1, #8b5cf6, #ec4899);

  --ok:          #10b981;
  --ok-bg:       rgba(16, 185, 129, 0.08);
  --ok-bdr:      rgba(16, 185, 129, 0.28);
  --no:          #f43f5e;
  --no-bg:       rgba(244, 63, 94, 0.08);
  --no-bdr:      rgba(244, 63, 94, 0.28);

  --bdr:         rgba(255, 255, 255, 0.08);
  --bdr-l:       rgba(255, 255, 255, 0.04);

  --r-sm: 8px; --r-md: 12px; --r-lg: 16px;
  --ease: .22s cubic-bezier(.4,0,.2,1);
  --font: 'Inter',-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
  --mono: 'JetBrains Mono',monospace;

  --sidebar-w: 290px;
  --topbar-h: 64px;
}

/* === TOKENS (Light Mode) === */
[data-theme="light"] {
  --bg:          #f8fafc;
  --bg-raised:   #ffffff;
  --bg-card:     #ffffff;
  --bg-card-h:   #f1f5f9;
  --bg-input:    #f8fafc;
  --bg-sidebar:  #f1f5f9;

  --text:        #0f172a;
  --text-2:      #475569;
  --text-3:      #94a3b8;

  --accent:      #4f46e5;
  --accent-l:    #6366f1;
  --accent-glow: rgba(79, 70, 229, 0.1);
  --grad:        linear-gradient(135deg, #4f46e5, #7c3aed, #db2777);

  --ok:          #059669;
  --ok-bg:       rgba(5, 150, 105, 0.06);
  --ok-bdr:      rgba(5, 150, 105, 0.22);
  --no:          #e11d48;
  --no-bg:       rgba(225, 29, 72, 0.06);
  --no-bdr:      rgba(225, 29, 72, 0.22);

  --bdr:         rgba(15, 23, 42, 0.08);
  --bdr-l:       rgba(15, 23, 42, 0.04);
}

html { scroll-behavior: smooth; }

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
  user-select: none;
  -webkit-user-select: none;
  overflow-x: hidden;
}

/* === WATERMARK === */
.watermark::before {
  content: "Prepared by " attr(data-owner);
  position: fixed; inset: 0; display: grid; place-items: center;
  transform: rotate(-28deg); font-size: clamp(34px,7vw,80px);
  color: rgba(99,102,241,.025); font-weight: 900; pointer-events: none; z-index: 0;
}

/* ================================================================
   TOP BAR
   ================================================================ */
.topbar {
  position: sticky; top: 0; z-index: 100;
  display: flex; align-items: center; justify-content: space-between;
  height: var(--topbar-h); padding: 0 20px;
  background: rgba(11,15,26,.88);
  backdrop-filter: blur(16px) saturate(1.4);
  -webkit-backdrop-filter: blur(16px) saturate(1.4);
  border-bottom: 1px solid var(--bdr);
}

.topbar-left { display: flex; align-items: center; gap: 10px; }

.menu-btn {
  display: none; background: none; border: none; color: var(--text-2);
  cursor: pointer; padding: 6px; border-radius: 6px;
}
.menu-btn:hover { color: var(--text); background: var(--bg-card); }

.brand { display: flex; align-items: center; gap: 10px; }
.brand-icon { flex-shrink: 0; }
.brand-icon svg { display: block; }

h1 {
  font-size: 17px; font-weight: 800; line-height: 1.15;
  background: var(--grad);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
}
.brand-sub { font-size: 11px; color: var(--text-3); margin-top: 1px; }

/* Progress + Score */
.topbar-center { display: flex; align-items: center; gap: 14px; }

.progress-ring {
  position: relative; width: 40px; height: 40px; flex-shrink: 0;
}
.progress-ring svg { display: block; }
.progress-ring span {
  position: absolute; inset: 0; display: grid; place-items: center;
  font-size: 9px; font-weight: 800; color: var(--ok);
  font-family: var(--mono);
}

.score-chips { display: flex; gap: 8px; }
.chip {
  display: flex; align-items: center; gap: 5px;
  padding: 4px 10px; border-radius: 20px; font-size: 13px; font-weight: 700;
  background: var(--bg-raised); border: 1px solid var(--bdr);
  font-family: var(--mono);
}
.chip-correct span { color: var(--ok); }
.chip-wrong span { color: var(--no); }

.total-badge {
  display: flex; flex-direction: column; align-items: center;
  padding: 6px 14px; border-radius: var(--r-sm);
  background: var(--accent-glow); border: 1px solid rgba(99,102,241,.18);
}
.total-badge span {
  font-size: 18px; font-weight: 900;
  background: var(--grad); -webkit-background-clip: text;
  -webkit-text-fill-color: transparent; background-clip: text;
  font-family: var(--mono);
}
.total-badge small { font-size: 9px; color: var(--text-3); text-transform: uppercase; letter-spacing: .07em; font-weight: 700; }

/* ================================================================
   LAYOUT SHELL
   ================================================================ */
.shell {
  position: relative; z-index: 1;
  display: grid; grid-template-columns: var(--sidebar-w) 1fr;
  min-height: calc(100vh - var(--topbar-h));
}

/* ================================================================
   SIDEBAR
   ================================================================ */
.sidebar {
  position: sticky; top: var(--topbar-h); height: calc(100vh - var(--topbar-h));
  overflow-y: auto; background: var(--bg-sidebar);
  border-right: 1px solid var(--bdr);
}
.sidebar::-webkit-scrollbar { width: 3px; }
.sidebar::-webkit-scrollbar-thumb { background: var(--bdr); border-radius: 3px; }

.sidebar-head { padding: 16px 14px 10px; }

.search-box {
  position: relative;
}
.search-ico { position: absolute; left: 10px; top: 50%; transform: translateY(-50%); color: var(--text-3); }
#searchBox {
  width: 100%; padding: 9px 10px 9px 34px;
  border: 1px solid var(--bdr); border-radius: var(--r-sm);
  background: var(--bg-input); color: var(--text);
  font-family: var(--font); font-size: 13px; outline: none;
  transition: border-color var(--ease), box-shadow var(--ease);
}
#searchBox::placeholder { color: var(--text-3); }
#searchBox:focus { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-glow); }

.unit-nav { padding: 0 14px 16px; display: grid; gap: 4px; }

.unit-btn {
  width: 100%; text-align: left; padding: 10px 12px;
  border: 1px solid var(--bdr-l); background: transparent;
  border-radius: var(--r-sm); color: var(--text);
  cursor: pointer; font-family: var(--font);
  transition: all var(--ease); position: relative;
}
.unit-btn::before {
  content: ''; position: absolute; left: 0; top: 4px; bottom: 4px; width: 3px;
  background: var(--grad); border-radius: 3px;
  transform: scaleY(0); transition: transform var(--ease);
}
.unit-btn:hover { background: var(--bg-card); border-color: rgba(99,102,241,.18); }
.unit-btn:hover::before, .unit-btn.active::before { transform: scaleY(1); }
.unit-btn.active { background: var(--accent-glow); border-color: rgba(99,102,241,.25); }

.unit-btn .u-mod { display: block; font-size: 10px; font-weight: 700; color: var(--accent-l); text-transform: uppercase; letter-spacing: .06em; margin-bottom: 2px; }
.unit-btn .u-name { display: block; font-size: 12px; font-weight: 500; color: var(--text-2); line-height: 1.35; }
.unit-btn .u-count {
  display: inline-block; margin-top: 4px; font-size: 10px; font-weight: 600;
  color: var(--text-3); background: var(--bg-raised); padding: 1px 8px;
  border-radius: 10px;
}

.sidebar-overlay {
  display: none; position: fixed; inset: 0; z-index: 49;
  background: rgba(0,0,0,.55);
}

/* ================================================================
   CONTENT
   ================================================================ */
.content { padding: 20px 28px 56px; min-width: 0; }

/* Unit header */
.unit-head {
  display: flex; align-items: flex-end; justify-content: space-between; gap: 14px;
  padding: 18px 22px; margin-bottom: 18px;
  background: var(--bg-raised); border: 1px solid var(--bdr);
  border-radius: var(--r-lg);
}
.module-tag {
  display: inline-block; font-size: 10px; font-weight: 700;
  text-transform: uppercase; letter-spacing: .1em;
  color: var(--accent-l); background: var(--accent-glow);
  padding: 2px 10px; border-radius: 10px; margin-bottom: 4px;
}
.unit-head h2 {
  margin: 0; font-size: clamp(16px,1.8vw,22px);
  font-weight: 700; color: var(--text); line-height: 1.3;
}
.meta-line { margin: 4px 0 0; color: var(--text-3); font-size: 12px; }
.unit-head-actions { display: flex; gap: 8px; flex-shrink: 0; }

/* Buttons */
.btn {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 8px 14px; border: none; border-radius: var(--r-sm);
  font-family: var(--font); font-size: 12px; font-weight: 600;
  cursor: pointer; transition: all var(--ease); white-space: nowrap;
}
.btn-accent { background: var(--accent); color: #fff; }
.btn-accent:hover { background: var(--accent-l); transform: translateY(-1px); box-shadow: 0 4px 16px rgba(99,102,241,.3); }
.btn-ghost { background: transparent; color: var(--text-2); border: 1px solid var(--bdr); }
.btn-ghost:hover { border-color: var(--accent); color: var(--accent-l); background: var(--accent-glow); }

/* ================================================================
   SUMMARY PANEL
   ================================================================ */
.summary-section {
  margin-bottom: 20px;
  border: 1px solid var(--bdr);
  border-radius: var(--r-lg);
  background: var(--bg-raised);
  overflow: hidden;
}

.summary-toggle {
  display: flex; align-items: center; justify-content: space-between;
  width: 100%; padding: 14px 20px;
  background: transparent; border: none; color: var(--text);
  cursor: pointer; font-family: var(--font); font-size: 14px; font-weight: 600;
  transition: background var(--ease);
}
.summary-toggle:hover { background: var(--bg-card); }
.summary-toggle-left { display: flex; align-items: center; gap: 10px; color: var(--accent-l); }
.summary-toggle-left span { color: var(--text); }

.chevron { transition: transform .25s ease; color: var(--text-3); }
.summary-section.open .chevron { transform: rotate(180deg); }

.summary-body {
  max-height: 0; overflow: hidden;
  transition: max-height .4s ease, padding .3s ease;
  padding: 0 20px;
}
.summary-section.open .summary-body {
  max-height: 4000px;
  padding: 0 20px 20px;
}

.summary-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 10px;
}

.summary-card {
  padding: 14px 16px;
  border: 1px solid var(--bdr);
  border-radius: var(--r-md);
  background: var(--bg-card);
  transition: border-color var(--ease), transform var(--ease);
}
.summary-card:hover { border-color: rgba(99,102,241,.2); transform: translateY(-1px); }

.summary-card strong {
  display: flex; align-items: center; gap: 6px;
  font-size: 13px; font-weight: 700; color: var(--accent-l); margin-bottom: 6px;
}
.summary-card strong::before {
  content: ''; display: inline-block; width: 6px; height: 6px;
  background: var(--accent); border-radius: 50%; flex-shrink: 0;
}
.summary-card p {
  margin: 0; color: var(--text-2); font-size: 12.5px; line-height: 1.55;
}

/* ================================================================
   QUESTION LIST
   ================================================================ */
.question-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(460px, 1fr));
  gap: 12px;
}

.chapter-title {
  grid-column: 1 / -1;
  margin: 6px 0;
  padding: 10px 16px;
  font-size: 14px; font-weight: 700;
  color: var(--accent-l);
  background: linear-gradient(135deg, var(--accent-glow), transparent);
  border-left: 4px solid var(--accent);
  border-radius: var(--r-sm);
}

/* Question card */
.question-card {
  padding: 16px 18px;
  background: var(--bg-card);
  border: 1px solid var(--bdr-l);
  border-radius: var(--r-md);
  transition: border-color var(--ease), box-shadow var(--ease);
  animation: cardUp .35s ease-out backwards;
}
.question-card:hover { border-color: rgba(99,102,241,.15); }

@keyframes cardUp { from { opacity: 0; transform: translateY(8px); } }

.q-num {
  display: inline-flex; align-items: center; justify-content: center;
  width: 24px; height: 24px; font-size: 10px; font-weight: 800;
  color: var(--accent-l); background: var(--accent-glow);
  border: 1px solid rgba(99,102,241,.18);
  border-radius: 50%; margin-bottom: 6px;
  font-family: var(--mono);
}
.q-text {
  margin: 0 0 10px;
  font-weight: 600; font-size: 13.5px; line-height: 1.55; color: var(--text);
}

/* Options */
.option {
  display: flex; align-items: flex-start; gap: 8px;
  width: 100%; padding: 9px 12px; margin: 4px 0;
  border-radius: var(--r-sm);
  font-size: 13px; line-height: 1.4;
  color: var(--text-2);
  background: var(--bg-raised);
  border: 1px solid var(--bdr-l);
  cursor: pointer; font-family: var(--font);
  text-align: left;
  transition: all var(--ease);
  position: relative;
}
.option:hover:not(:disabled) {
  border-color: rgba(99,102,241,.25);
  background: var(--bg-card-h);
  color: var(--text);
  transform: translateX(3px);
}
.option .opt-letter {
  flex-shrink: 0;
  display: inline-flex; align-items: center; justify-content: center;
  width: 22px; height: 22px; font-size: 10px; font-weight: 700;
  border-radius: 5px;
  background: var(--bg); border: 1px solid var(--bdr);
  color: var(--text-3);
  transition: all var(--ease);
  font-family: var(--mono);
}
.option:hover:not(:disabled) .opt-letter { border-color: var(--accent); color: var(--accent-l); }

/* States */
.option.correct {
  background: var(--ok-bg); border-color: var(--ok-bdr); color: var(--ok); cursor: default;
}
.option.correct .opt-letter { background: var(--ok); color: #fff; border-color: var(--ok); }
.option.correct::after {
  content: '✓'; position: absolute; right: 12px; top: 50%; transform: translateY(-50%);
  font-weight: 800; font-size: 14px; color: var(--ok);
}

.option.wrong {
  background: var(--no-bg); border-color: var(--no-bdr); color: var(--no);
  opacity: .8; cursor: default;
}
.option.wrong .opt-letter { background: var(--no); color: #fff; border-color: var(--no); }
.option.wrong::after {
  content: '✗'; position: absolute; right: 12px; top: 50%; transform: translateY(-50%);
  font-weight: 800; font-size: 14px; color: var(--no);
}

.option:disabled { cursor: default; }
.option:disabled:not(.correct):not(.wrong) { opacity: .35; }

/* Answer explanation */
.inline-answer {
  margin-top: 10px; padding: 10px 14px;
  background: linear-gradient(135deg, rgba(34,197,94,.07), rgba(34,197,94,.02));
  border: 1px solid var(--ok-bdr);
  border-radius: var(--r-sm);
  font-size: 12px; line-height: 1.55;
  animation: revealAnswer .3s ease-out;
}
@keyframes revealAnswer { from { opacity: 0; transform: translateY(-6px); } }

.inline-answer strong { display: block; color: var(--ok); margin-bottom: 3px; font-size: 12px; }
.inline-answer p { margin: 0; color: var(--text-2); }

/* Card answered */
.question-card.card-correct { border-color: var(--ok-bdr); }
.question-card.card-wrong { border-color: var(--no-bdr); }

@keyframes flashOk {
  0% { box-shadow: 0 0 0 0 rgba(34,197,94,.35); }
  100% { box-shadow: 0 0 0 10px rgba(34,197,94,0); }
}
@keyframes flashNo {
  0%,100% { transform: translateX(0); }
  20%,60% { transform: translateX(-3px); }
  40%,80% { transform: translateX(3px); }
}
.flash-ok { animation: flashOk .5s ease-out; }
.flash-no { animation: flashNo .35s ease-out; }

/* ================================================================
   FOOTER
   ================================================================ */
footer {
  position: relative; z-index: 1;
  display: flex; justify-content: space-between; align-items: center;
  padding: 14px 28px;
  color: var(--text-3); border-top: 1px solid var(--bdr);
  background: var(--bg-sidebar); font-size: 12px;
}
.footer-right { font-size: 11px; }

/* ================================================================
   RESPONSIVE
   ================================================================ */
@media (max-width: 1100px) {
  .question-list { grid-template-columns: 1fr; }
}

@media (max-width: 900px) {
  .shell { grid-template-columns: 1fr; }

  .sidebar {
    position: fixed; top: var(--topbar-h); left: 0; bottom: 0;
    width: 280px; z-index: 50;
    transform: translateX(-100%);
    transition: transform .3s ease;
    box-shadow: 8px 0 24px rgba(0,0,0,.4);
  }
  .sidebar.open { transform: translateX(0); }
  .sidebar-overlay.show { display: block; }

  .menu-btn { display: flex; }

  .content { padding: 16px 14px 48px; }
  .unit-head { flex-direction: column; align-items: stretch; }

  .summary-grid { grid-template-columns: 1fr; }
  .question-list { grid-template-columns: 1fr; }

  .topbar-center { gap: 8px; }
  footer { flex-direction: column; gap: 4px; text-align: center; }
}

@media (max-width: 540px) {
  h1 { font-size: 14px; }
  .brand-icon { display: none; }
  .total-badge { padding: 4px 10px; }
  .total-badge span { font-size: 15px; }
  .progress-ring { width: 34px; height: 34px; }
  .progress-ring span { font-size: 8px; }
  .chip { padding: 3px 8px; font-size: 12px; }
  .btn { padding: 7px 10px; font-size: 11px; }
  .btn svg { display: none; }
}

@media print { body { display: none; } }

/* ================================================================
   SCORE POP
   ================================================================ */
@keyframes pop { 0% { transform: scale(1); } 50% { transform: scale(1.4); } 100% { transform: scale(1); } }
.score-pop { animation: pop .28s ease-out; }

/* ================================================================
   WELCOME & CONNECT GATE
   ================================================================ */
.welcome-gate {
  position: fixed;
  inset: 0;
  z-index: 1000;
  display: grid;
  place-items: center;
  padding: 20px;
  background: rgba(8, 12, 21, 0.82);
  backdrop-filter: blur(20px) saturate(1.6);
  -webkit-backdrop-filter: blur(20px) saturate(1.6);
  transition: opacity 0.4s cubic-bezier(0.4, 0, 0.2, 1), visibility 0.4s;
  opacity: 1;
  visibility: visible;
}
.welcome-gate.dismissed {
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

.welcome-card {
  width: 100%;
  max-width: 500px;
  background: linear-gradient(135deg, rgba(21, 29, 46, 0.95), rgba(13, 19, 33, 0.95));
  border: 1px solid rgba(99, 102, 241, 0.25);
  border-radius: var(--r-lg);
  padding: 40px 32px;
  text-align: center;
  box-shadow: 0 25px 60px rgba(0, 0, 0, 0.65), 0 0 50px rgba(99, 102, 241, 0.15);
  transform: scale(0.95);
  transition: transform 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
  animation: welcomeShow 0.5s 0.1s cubic-bezier(0.34, 1.56, 0.64, 1) forwards;
}

@keyframes welcomeShow {
  to { transform: scale(1); }
}

.welcome-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 84px;
  height: 84px;
  background: rgba(99, 102, 241, 0.08);
  border: 1.5px solid rgba(99, 102, 241, 0.2);
  border-radius: 50%;
  margin-bottom: 24px;
  box-shadow: 0 0 35px rgba(99, 102, 241, 0.2);
  color: var(--accent-l);
}
.welcome-icon svg {
  color: #0077b5;
  filter: drop-shadow(0 0 8px rgba(0, 119, 181, 0.4));
}

.welcome-card h2 {
  font-size: 23px;
  font-weight: 800;
  margin-bottom: 12px;
  background: var(--grad);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.welcome-message {
  font-size: 14px;
  color: var(--text-2);
  line-height: 1.6;
  margin-bottom: 30px;
}

.welcome-actions {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 26px;
}

.btn-welcome {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 13px 24px;
  border: none;
  border-radius: var(--r-md);
  font-family: var(--font);
  font-size: 14px;
  font-weight: 700;
  cursor: pointer;
  transition: all var(--ease);
  text-decoration: none;
}

.btn-linkedin {
  background: linear-gradient(135deg, #0077b5, #005c8d);
  color: #ffffff;
  box-shadow: 0 4px 20px rgba(0, 119, 181, 0.4);
}
.btn-linkedin:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(0, 119, 181, 0.55), 0 0 15px rgba(0, 119, 181, 0.3);
}

.btn-enter {
  background: var(--bg-raised);
  color: var(--text);
  border: 1px solid var(--bdr);
}
.btn-enter:hover {
  border-color: var(--accent);
  color: var(--accent-l);
  background: var(--accent-glow);
  transform: translateY(-2px);
}
.btn-enter svg {
  transition: transform var(--ease);
}
.btn-enter:hover svg {
  transform: translateX(4px);
}

.welcome-footer {
  font-size: 12px;
  color: var(--text-3);
  border-top: 1px solid var(--bdr-l);
  padding-top: 20px;
}
.welcome-footer a {
  color: var(--accent-l);
  text-decoration: none;
  font-weight: 600;
  transition: color var(--ease);
}
.welcome-footer a:hover {
  color: var(--accent);
  text-decoration: underline;
}

/* Footer Link Modifications */
.footer-links {
  display: flex;
  gap: 18px;
  align-items: center;
}
.footer-link {
  color: var(--text-3);
  text-decoration: none;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: color var(--ease), transform var(--ease);
}
.footer-link:hover {
  color: var(--accent-l);
  transform: translateY(-1px);
}
.footer-link-owner {
  color: var(--text-2);
  text-decoration: none;
  font-weight: 600;
  transition: color var(--ease);
}
.footer-link-owner:hover {
  color: var(--accent-l);
  text-decoration: underline;
}

@media (max-width: 600px) {
  .welcome-card {
    padding: 30px 20px;
  }
  .welcome-card h2 {
    font-size: 20px;
  }
}

/* ================================================================
   LINK VISIBILITY ENHANCEMENTS
   ================================================================ */
/* Clickable Branding Creator Link */
.brand-sub-link {
  color: var(--text-3);
  text-decoration: none;
  font-weight: 700;
  transition: color var(--ease), text-shadow var(--ease);
}
.brand-sub-link:hover {
  color: var(--accent-l);
  text-shadow: 0 0 8px rgba(99, 102, 241, 0.4);
}

/* Header Website Button Alignment */
.topbar-right {
  display: flex;
  align-items: center;
  gap: 12px;
}
.btn-header-web {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--accent-glow);
  border: 1px solid rgba(99, 102, 241, 0.2);
  color: var(--accent-l);
  padding: 7px 12px;
  border-radius: var(--r-sm);
  font-size: 12px;
  font-weight: 700;
  text-decoration: none;
  transition: all var(--ease);
}
.btn-header-web:hover {
  background: var(--accent);
  color: #ffffff;
  border-color: var(--accent-l);
  box-shadow: 0 4px 15px rgba(99, 102, 241, 0.35);
  transform: translateY(-1px);
}
.btn-header-web svg {
  transition: transform var(--ease);
}
.btn-header-web:hover svg {
  transform: scale(1.1);
}

/* Sidebar Promotional Card */
.sidebar {
  display: flex;
  flex-direction: column;
}
.unit-nav {
  flex-grow: 1;
}
.sidebar-promo {
  padding: 16px 14px;
  border-top: 1px solid var(--bdr-l);
  margin-top: 20px;
}
.sidebar-promo-card {
  background: linear-gradient(135deg, rgba(21, 29, 46, 0.85), rgba(17, 24, 39, 0.85));
  border: 1px solid rgba(99, 102, 241, 0.18);
  border-radius: var(--r-md);
  padding: 16px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.2);
  transition: border-color var(--ease), box-shadow var(--ease);
}
.sidebar-promo-card:hover {
  border-color: rgba(99, 102, 241, 0.35);
  box-shadow: 0 12px 30px rgba(99, 102, 241, 0.08);
}
.promo-title {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 11.5px;
  font-weight: 800;
  color: var(--accent-l);
  margin-bottom: 8px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.promo-title svg {
  color: var(--accent);
}
.sidebar-promo-card p {
  font-size: 11.5px;
  color: var(--text-2);
  line-height: 1.5;
  margin-bottom: 12px;
}
.btn-promo {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  width: 100%;
  padding: 8px 12px;
  background: var(--accent);
  color: #ffffff;
  border: none;
  border-radius: var(--r-sm);
  font-family: var(--font);
  font-size: 11.5px;
  font-weight: 700;
  cursor: pointer;
  text-decoration: none;
  transition: all var(--ease);
}
.btn-promo:hover {
  background: var(--accent-l);
  box-shadow: 0 4px 15px rgba(99, 102, 241, 0.3);
  transform: translateY(-1px);
}
.btn-promo svg {
  transition: transform var(--ease);
}
.btn-promo:hover svg {
  transform: translate(2px, -1px);
}

@media (max-width: 900px) {
  .sidebar-promo {
    margin-top: 15px;
    padding-bottom: 24px;
  }
}
@media (max-width: 540px) {
  .btn-header-web span {
    display: none;
  }
  .btn-header-web {
    padding: 6px 8px;
  }
  .topbar-right {
    gap: 8px;
  }
}

/* ================================================================
   EMAIL AUTHENTICATION SYSTEM
   ================================================================ */
.auth-container {
  position: relative;
}
.auth-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: all var(--ease);
}
.auth-btn:hover {
  transform: translateY(-1px);
}
.auth-dropdown {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  width: 210px;
  background: var(--bg-card);
  border: 1px solid var(--bdr);
  border-radius: var(--r-md);
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.55), 0 0 25px rgba(99, 102, 241, 0.08);
  padding: 14px;
  z-index: 200;
  display: none;
  animation: dropdownFadeIn 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}
.auth-dropdown.show {
  display: block;
}
@keyframes dropdownFadeIn {
  from { opacity: 0; transform: translateY(-8px); }
  to { opacity: 1; transform: translateY(0); }
}
.auth-dropdown .user-info {
  border-bottom: 1px solid var(--bdr-l);
  padding-bottom: 10px;
  margin-bottom: 10px;
}
.auth-dropdown .user-info small {
  display: block;
  font-size: 9px;
  color: var(--text-3);
  text-transform: uppercase;
  font-weight: 700;
  letter-spacing: 0.05em;
  margin-bottom: 2px;
}
.auth-dropdown .user-info span {
  display: block;
  font-size: 12px;
  color: var(--text-2);
  word-break: break-all;
  font-weight: 600;
}
.btn-dropdown-logout {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  width: 100%;
  padding: 9px;
  background: var(--no-bg);
  border: 1px solid var(--no-bdr);
  border-radius: var(--r-sm);
  color: var(--no);
  font-family: var(--font);
  font-size: 12px;
  font-weight: 700;
  cursor: pointer;
  transition: all var(--ease);
}
.btn-dropdown-logout:hover {
  background: var(--no);
  color: #fff;
  border-color: var(--no);
}

/* Glassmorphic Auth Modal Overlay */
.auth-modal-overlay {
  position: fixed;
  inset: 0;
  z-index: 1100;
  display: grid;
  place-items: center;
  padding: 20px;
  background: rgba(8, 12, 21, 0.84);
  backdrop-filter: blur(20px) saturate(1.6);
  -webkit-backdrop-filter: blur(20px) saturate(1.6);
  transition: opacity 0.35s cubic-bezier(0.4, 0, 0.2, 1), visibility 0.35s;
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}
.auth-modal-overlay.open {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
}
.auth-card {
  position: relative;
  width: 100%;
  max-width: 410px;
  background: linear-gradient(135deg, rgba(21, 29, 46, 0.95), rgba(13, 19, 33, 0.95));
  border: 1px solid rgba(99, 102, 241, 0.25);
  border-radius: var(--r-lg);
  padding: 36px 30px;
  box-shadow: 0 25px 60px rgba(0, 0, 0, 0.65), 0 0 50px rgba(99, 102, 241, 0.15);
  transform: translateY(20px);
  transition: transform 0.35s cubic-bezier(0.34, 1.56, 0.64, 1);
}
.auth-modal-overlay.open .auth-card {
  transform: translateY(0);
}
.auth-close {
  position: absolute;
  top: 18px;
  right: 18px;
  background: transparent;
  border: none;
  color: var(--text-3);
  font-size: 26px;
  line-height: 1;
  cursor: pointer;
  transition: color var(--ease);
}
.auth-close:hover {
  color: var(--text);
}
.auth-header {
  text-align: center;
  margin-bottom: 24px;
}
.brand-icon-modal {
  display: inline-block;
  margin-bottom: 12px;
}
.auth-header h2 {
  font-size: 21px;
  font-weight: 800;
  margin-bottom: 6px;
  background: var(--grad);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.auth-header p {
  font-size: 12px;
  color: var(--text-3);
}

/* Tabs */
.auth-tabs {
  display: flex;
  background: var(--bg-raised);
  border: 1px solid var(--bdr);
  border-radius: var(--r-sm);
  padding: 4px;
  margin-bottom: 22px;
}
.auth-tab-btn {
  flex: 1;
  background: transparent;
  border: none;
  padding: 9px;
  font-family: var(--font);
  font-size: 13px;
  font-weight: 700;
  color: var(--text-3);
  cursor: pointer;
  border-radius: 5px;
  transition: all var(--ease);
}
.auth-tab-btn.active {
  background: var(--bg-card);
  color: var(--accent-l);
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
}

/* Form fields */
.auth-form {
  display: flex;
  flex-direction: column;
  gap: 16px;
}
.form-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.form-group label {
  font-size: 11px;
  font-weight: 700;
  color: var(--text-2);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.form-group input {
  padding: 10px 12px;
  border: 1px solid var(--bdr);
  border-radius: var(--r-sm);
  background: var(--bg-input);
  color: var(--text);
  font-family: var(--font);
  font-size: 13.5px;
  outline: none;
  transition: border-color var(--ease), box-shadow var(--ease);
}
.form-group input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-glow);
}
.btn-auth-submit {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: var(--r-sm);
  font-family: var(--font);
  font-size: 13px;
  font-weight: 700;
  cursor: pointer;
  transition: all var(--ease);
  margin-top: 8px;
}
.btn-auth-submit:hover {
  background: var(--accent-l);
  box-shadow: 0 4px 16px rgba(99, 102, 241, 0.35);
  transform: translateY(-1px);
}
.btn-auth-submit svg {
  transition: transform var(--ease);
}
.btn-auth-submit:hover svg {
  transform: translateX(3px);
}

/* Alerts */
.auth-alert {
  padding: 10px 12px;
  border-radius: var(--r-sm);
  font-size: 12.5px;
  line-height: 1.5;
  font-weight: 600;
}
.auth-alert.success {
  background: var(--ok-bg);
  border: 1px solid var(--ok-bdr);
  color: var(--ok);
}
.auth-alert.error {
  background: var(--no-bg);
  border: 1px solid var(--no-bdr);
  color: var(--no);
}
.auth-alert.hide {
  display: none;
}

/* ================================================================
   WRONG ANSWERS / REVIEW MODE
   ================================================================ */
/* Make wrong chip clickable */
.chip-wrong {
  cursor: pointer;
  border: 1px solid var(--no-bdr);
  background: var(--no-bg);
  transition: all var(--ease);
  font-family: var(--mono);
}
.chip-wrong:hover {
  background: var(--no);
  color: #fff;
  border-color: var(--no);
  box-shadow: 0 0 12px rgba(239, 68, 68, 0.4);
}
.chip-wrong:hover svg circle {
  stroke: #ffffff;
}
.chip-wrong:hover svg path {
  stroke: #ffffff;
}

/* Sidebar button */
.review-mistakes-btn {
  border: 1.5px solid rgba(23ef, 68, 68, 0.18) !important;
  transition: all var(--ease) !important;
  margin-top: 12px;
}
.review-mistakes-btn::before {
  background: linear-gradient(135deg, #ef4444, #f87171) !important;
}
.review-mistakes-btn:hover {
  background: rgba(239, 68, 68, 0.08) !important;
  border-color: rgba(239, 68, 68, 0.35) !important;
}
.review-mistakes-btn.active {
  background: rgba(239, 68, 68, 0.12) !important;
  border-color: rgba(239, 68, 68, 0.45) !important;
}
.review-mistakes-btn .u-mod {
  color: #f87171 !important;
}
.review-mistakes-btn .u-count {
  color: #f87171 !important;
  background: rgba(239, 68, 68, 0.15) !important;
}

/* Mistakes review view heading */
.review-mode-title {
  background: linear-gradient(135deg, #ef4444, #f87171) !important;
  -webkit-background-clip: text !important;
  -webkit-text-fill-color: transparent !important;
  background-clip: text !important;
}
.review-mode-tag {
  color: #f87171 !important;
  background: rgba(239, 68, 68, 0.1) !important;
}
.review-head-border {
  border-color: rgba(239, 68, 68, 0.28) !important;
}

/* Empty State style */
.review-empty-state {
  grid-column: 1 / -1;
  text-align: center;
  padding: 64px 32px;
  background: var(--bg-card);
  border: 2px dashed rgba(99, 102, 241, 0.2);
  border-radius: var(--r-lg);
  margin-top: 10px;
}
.review-empty-icon {
  font-size: 56px;
  margin-bottom: 20px;
  display: inline-block;
  animation: floatIcon 2.5s infinite ease-in-out;
}
@keyframes floatIcon {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-8px); }
}
.review-empty-state h3 {
  font-size: 20px;
  font-weight: 700;
  margin-bottom: 8px;
  color: var(--text);
}
.review-empty-state p {
  font-size: 13.5px;
  color: var(--text-2);
  max-width: 400px;
  margin: 0 auto 24px;
  line-height: 1.6;
}

/* Theme Switcher Toggle button */
.btn-theme {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 8px;
  width: 34px;
  height: 34px;
  border-radius: var(--r-sm);
  color: var(--text-2);
  cursor: pointer;
  background: transparent;
  border: 1px solid var(--bdr);
  transition: all var(--ease);
}
.btn-theme:hover {
  color: var(--text);
  background: var(--bg-card-h);
  border-color: var(--accent-l);
}
.sun-icon { display: block; }
.moon-icon { display: none; }

[data-theme="light"] .sun-icon { display: none; }
[data-theme="light"] .moon-icon { display: block; }