:root {
  --bg-dark: #0f1220;
  --surface: rgba(255, 255, 255, 0.96);
  --surface-soft: rgba(255, 255, 255, 0.82);
  --ink: #161a2d;
  --muted: #687087;
  --line: rgba(22, 26, 45, 0.12);
  --primary: #5b3df5;
  --primary-2: #1d8cf8;
  --success: #169c5a;
  --warning: #ffb020;
  --danger: #e5484d;
  --shadow-lg: 0 28px 70px rgba(7, 10, 24, 0.28);
  --shadow-sm: 0 10px 24px rgba(13, 18, 35, 0.12);
  --radius-lg: 28px;
  --radius-md: 20px;
  --radius-sm: 14px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  color: #fff;
  font-family: Inter, ui-sans-serif, system-ui, Segoe UI, Arial, sans-serif;
  background:
    radial-gradient(circle at 15% 10%, rgba(105, 76, 255, 0.8) 0 14%, transparent 30%),
    radial-gradient(circle at 86% 14%, rgba(0, 194, 255, 0.8) 0 12%, transparent 28%),
    linear-gradient(135deg, #171b2d 0%, #24145d 48%, #009c90 100%);
  background-attachment: fixed;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  background:
    linear-gradient(rgba(255, 255, 255, 0.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.05) 1px, transparent 1px);
  background-size: 42px 42px;
  mask-image: linear-gradient(to bottom, rgba(0, 0, 0, 0.9), transparent);
}

a {
  color: inherit;
  text-decoration: none;
}

.navbar {
  min-height: 72px;
  background: rgba(11, 14, 29, 0.52);
  backdrop-filter: blur(18px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.12);
}

.navbar b {
  font-size: 1.2rem;
  font-weight: 900;
  letter-spacing: 0.04em;
}

.avatar,
.ranking img,
.me img {
  width: 42px;
  height: 42px;
  border-radius: 50%;
  object-fit: cover;
  border: 2px solid rgba(255, 255, 255, 0.74);
  background: rgba(255, 255, 255, 0.35);
}

.container,
.play-shell,
.join-screen {
  position: relative;
  z-index: 1;
}

.hero {
  min-height: 460px;
  padding: 56px;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
  position: relative;
  display: flex;
  align-items: flex-end;
  background:
    linear-gradient(90deg, rgba(8, 11, 26, 0.82), rgba(8, 11, 26, 0.3)),
    url('https://images.unsplash.com/photo-1584036561566-baf8f5f1b144?auto=format&fit=crop&w=1600&q=80') center/cover;
}

.hero::after {
  content: "";
  position: absolute;
  inset: auto 0 0 0;
  height: 8px;
  background: linear-gradient(90deg, #ff4d6d, #4169ff, #ffb020, #19b46b);
}

.hero h1 {
  font-size: clamp(2.5rem, 6vw, 5rem);
  line-height: 0.95;
  font-weight: 950;
  max-width: 920px;
  margin: 0 0 18px;
}

.hero p {
  max-width: 720px;
  font-size: 1.15rem;
  color: rgba(255, 255, 255, 0.88);
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

.panel,
.join-card,
.stage {
  background: var(--surface);
  color: var(--ink);
  border-radius: var(--radius-md);
  border: 1px solid rgba(255, 255, 255, 0.55);
  box-shadow: var(--shadow-lg);
  padding: 24px;
}

.hero-panel {
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.98), rgba(245, 247, 255, 0.96));
}

.panel h2,
.join-card h1,
.stage h2,
.hero-panel h2 {
  margin: 0 0 10px;
  font-weight: 900;
}

.panel h3 {
  margin: 0 0 14px;
  font-weight: 800;
}

.panel-heading,
.topbar,
.play-header {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  align-items: flex-start;
}

.topbar {
  margin-bottom: 18px;
}

.small-muted {
  color: var(--muted);
}

.pill,
.status-chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  border-radius: 999px;
  padding: 8px 14px;
  font-size: 0.85rem;
  font-weight: 800;
  letter-spacing: 0.02em;
}

.pill {
  background: rgba(91, 61, 245, 0.12);
  color: var(--primary);
}

.status-chip {
  background: rgba(29, 140, 248, 0.1);
  color: var(--primary-2);
  white-space: nowrap;
}

.feature-grid {
  display: grid;
  gap: 16px;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
}

.mini-card {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 18px;
  border-radius: var(--radius-sm);
  background: rgba(255, 255, 255, 0.14);
  border: 1px solid rgba(255, 255, 255, 0.14);
  color: #fff;
  backdrop-filter: blur(12px);
}

.join-card .mini-card,
.panel .mini-card,
.installer-card .mini-card {
  color: var(--ink);
  background: rgba(91, 61, 245, 0.06);
  border: 1px solid rgba(91, 61, 245, 0.12);
}

.option-list {
  display: grid;
  gap: 10px;
}

.option-stack span,
.option-list span {
  display: block;
  padding: 12px 14px;
  border-radius: 14px;
  background: rgba(91, 61, 245, 0.07);
  border: 1px solid rgba(91, 61, 245, 0.1);
  font-weight: 600;
}

.join-screen {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 24px;
}

.join-card,
.installer-card {
  width: min(100%, 620px);
}

.stack-form {
  display: grid;
  gap: 12px;
}

.stack-form label {
  font-weight: 700;
  margin-top: 6px;
}

.join-card .form-control,
.panel .form-control,
.installer-card .form-control {
  min-height: 52px;
  border-radius: 14px;
  border: 1px solid rgba(22, 26, 45, 0.12);
  background: rgba(248, 250, 255, 0.92);
}

.form-control:focus {
  border-color: rgba(91, 61, 245, 0.5);
  box-shadow: 0 0 0 0.25rem rgba(91, 61, 245, 0.16);
}

.install-note,
.empty-state,
.link-box {
  padding: 16px 18px;
  border-radius: 16px;
  border: 1px solid var(--line);
  background: rgba(245, 247, 255, 0.95);
  color: var(--ink);
}

.maintenance-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.room-grid {
  display: grid;
  gap: 14px;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
}

.room-card {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 18px;
  border-radius: 18px;
  color: #fff;
  background: rgba(255, 255, 255, 0.12);
  border: 1px solid rgba(255, 255, 255, 0.16);
  backdrop-filter: blur(12px);
  box-shadow: var(--shadow-sm);
  transition: transform 0.18s ease, background 0.18s ease;
}

.room-card:hover,
.room-card.active {
  transform: translateY(-2px);
  background: rgba(255, 255, 255, 0.2);
}

.room-card strong {
  font-size: 1.15rem;
}

.room-card small,
.room-card span {
  opacity: 0.86;
}

.admin-tools {
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.99), rgba(247, 244, 255, 0.96));
}

.builder-grid {
  display: grid;
  gap: 18px;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.manage-grid {
  display: grid;
  gap: 12px;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.control-grid {
  display: grid;
  grid-template-columns: minmax(280px, 340px) minmax(280px, 1fr) minmax(280px, 1fr);
  gap: 18px;
  align-items: start;
}

.qr img {
  width: 100%;
  max-width: 260px;
  display: block;
  margin: 18px auto;
  border-radius: 20px;
  background: #fff;
  padding: 12px;
}

.code {
  margin: 0 0 16px;
  text-align: center;
  font-size: 2rem;
  font-weight: 900;
  letter-spacing: 0.16em;
}

.btn-grid {
  display: grid;
  gap: 12px;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.btn,
.hero .btn {
  border-radius: 14px;
  font-weight: 800;
  border: 0;
  box-shadow: var(--shadow-sm);
}

.stats {
  display: grid;
  gap: 12px;
}

.stat-grid {
  display: grid;
  gap: 12px;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.stat-card {
  padding: 14px;
  border-radius: 16px;
  background: rgba(91, 61, 245, 0.06);
  border: 1px solid rgba(91, 61, 245, 0.08);
}

.stat-card span {
  display: block;
  font-size: 0.85rem;
  color: var(--muted);
}

.stat-card strong {
  display: block;
  margin-top: 4px;
  font-size: 1.1rem;
}

.meter {
  width: 100%;
  height: 16px;
  border-radius: 999px;
  overflow: hidden;
  background: rgba(91, 61, 245, 0.08);
}

.meter i {
  display: block;
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--primary), var(--primary-2));
}

.meter-caption {
  margin-top: 10px;
  color: var(--muted);
  font-size: 0.92rem;
}

.submission-list {
  display: grid;
  gap: 10px;
}

.submission-card {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 14px 16px;
  border-radius: 16px;
  background: rgba(248, 250, 255, 0.98);
  border: 1px solid rgba(22, 26, 45, 0.08);
}

.submission-user {
  display: flex;
  align-items: center;
  gap: 12px;
}

.submission-user img {
  width: 42px;
  height: 42px;
  border-radius: 50%;
  object-fit: cover;
}

.submission-user strong,
.submission-user span {
  display: block;
}

.submission-user span {
  color: var(--muted);
  font-size: 0.92rem;
}

.submission-result {
  padding: 8px 12px;
  border-radius: 999px;
  font-weight: 800;
  font-size: 0.88rem;
  white-space: nowrap;
}

.submission-result.is-correct {
  background: rgba(22, 156, 90, 0.12);
  color: var(--success);
}

.submission-result.is-wrong {
  background: rgba(229, 72, 77, 0.12);
  color: var(--danger);
}

.question-bank {
  display: grid;
  gap: 14px;
}

.question-item {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: flex-start;
  padding: 16px 18px;
  border: 1px solid rgba(22, 26, 45, 0.08);
  border-radius: 18px;
  background: rgba(248, 250, 255, 0.96);
}

.question-item strong {
  display: block;
  font-size: 1rem;
}

.empty-panel {
  min-height: 110px;
  display: flex;
  align-items: center;
}

.ranking {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 12px;
}

.ranking li,
.empty-list {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 16px;
  border-radius: 16px;
  background: rgba(248, 250, 255, 0.96);
  border: 1px solid rgba(22, 26, 45, 0.08);
}

.ranking li span {
  flex: 1;
  min-width: 0;
  font-weight: 700;
}

.ranking li b {
  white-space: nowrap;
}

.compact li {
  padding: 12px 14px;
}

.play-shell {
  width: min(100%, 1080px);
  margin: 0 auto;
  padding: 24px;
  display: grid;
  gap: 18px;
}

.me {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 16px;
  border-radius: 18px;
  background: rgba(255, 255, 255, 0.14);
  backdrop-filter: blur(14px);
}

.me > div,
.me {
  color: #fff;
}

.me span {
  display: block;
  opacity: 0.9;
}

.stage {
  min-height: 360px;
  display: grid;
  align-content: center;
  justify-items: center;
  text-align: center;
  gap: 12px;
}

.timer {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 96px;
  height: 96px;
  border-radius: 50%;
  font-size: 2rem;
  font-weight: 900;
  color: var(--primary);
  background: rgba(91, 61, 245, 0.08);
  border: 6px solid rgba(91, 61, 245, 0.14);
}

.answers {
  width: 100%;
  display: grid;
  gap: 14px;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin-top: 8px;
}

.answer-btn {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 16px;
  border: 1px solid rgba(22, 26, 45, 0.08);
  border-radius: 18px;
  background: #fff;
  color: var(--ink);
  text-align: left;
  font-weight: 700;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.answer-btn:hover:not(:disabled) {
  transform: translateY(-2px);
  box-shadow: var(--shadow-sm);
}

.answer-btn:disabled {
  opacity: 0.72;
}

.answer-btn b {
  width: 42px;
  height: 42px;
  border-radius: 12px;
  display: inline-grid;
  place-items: center;
  color: #fff;
}

.opt-A b {
  background: #ff4d6d;
}

.opt-B b {
  background: #4169ff;
}

.opt-C b {
  background: #ffb020;
}

.opt-D b {
  background: #19b46b;
}

.answer-btn.sent {
  border-color: rgba(22, 156, 90, 0.4);
  background: rgba(22, 156, 90, 0.08);
}

.answer-btn.bad,
.bad {
  color: var(--danger);
}

.response-note,
.reveal,
.answer {
  width: 100%;
  padding: 16px 18px;
  border-radius: 16px;
  background: rgba(91, 61, 245, 0.06);
  border: 1px solid rgba(91, 61, 245, 0.1);
}

.reveal p,
.answer p {
  margin: 8px 0 0;
}

.alert {
  border-radius: 16px;
}

.avatar-picker {
  display: grid;
  gap: 12px;
  grid-template-columns: repeat(auto-fit, minmax(96px, 1fr));
}

.avatar-option {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  padding: 12px;
  border: 1px solid rgba(22, 26, 45, 0.08);
  border-radius: 16px;
  background: rgba(248, 250, 255, 0.96);
  color: var(--ink);
  font-weight: 700;
  transition: transform 0.15s ease, border-color 0.15s ease, box-shadow 0.15s ease;
}

.avatar-option img {
  width: 64px;
  height: 64px;
  border-radius: 18px;
}

.avatar-option.active,
.avatar-option:hover {
  transform: translateY(-2px);
  border-color: rgba(91, 61, 245, 0.35);
  box-shadow: var(--shadow-sm);
}

.good {
  color: var(--success);
  font-weight: 800;
}

.credit-line {
  margin: 18px 0 0;
  text-align: center;
  color: rgba(255, 255, 255, 0.86);
  font-weight: 800;
  letter-spacing: 0.04em;
}

hr {
  margin: 24px 0;
  border-color: rgba(22, 26, 45, 0.08);
}

@media (max-width: 991px) {
  .hero {
    min-height: 400px;
    padding: 32px;
  }

  .control-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 767px) {
  .panel-heading,
  .topbar,
  .play-header,
  .maintenance-actions {
    flex-direction: column;
  }

  .answers,
  .btn-grid,
  .stat-grid,
  .manage-grid,
  .builder-grid {
    grid-template-columns: 1fr;
  }

  .question-item {
    flex-direction: column;
  }

  .hero h1 {
    font-size: 2.5rem;
  }

  .hero,
  .panel,
  .join-card,
  .stage {
    padding: 20px;
  }

  .play-shell {
    padding: 16px;
  }
}