* {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
  font-family: Arial, sans-serif;
  background: #f4f6fb;
  color: #1f2937;
}

body {
  min-height: 100vh;
}

button,
input,
select,
textarea,
a {
  font: inherit;
}

button {
  border: none;
  border-radius: 10px;
  padding: 10px 14px;
  background: #2563eb;
  color: #ffffff;
  cursor: pointer;
  transition: 0.2s ease;
}

button:hover {
  background: #1d4ed8;
}

button:disabled {
  background: #94a3b8;
  cursor: not-allowed;
}

input,
select,
textarea {
  width: 100%;
  border: 1px solid #cbd5e1;
  border-radius: 10px;
  padding: 10px 12px;
  background: #ffffff;
}

textarea {
  resize: vertical;
  min-height: 160px;
}

a {
  text-decoration: none;
}

.menu-shell {
  display: grid;
  grid-template-columns: 260px 1fr;
  min-height: 100vh;
}

.sidebar {
  background: #0f172a;
  color: #ffffff;
  padding: 24px 18px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.brand h1 {
  margin: 0 0 6px 0;
  font-size: 24px;
}

.brand p {
  margin: 0;
  color: #cbd5e1;
}

.sidebar-links {
  display: grid;
  gap: 10px;
  margin-top: 24px;
}

.sidebar-link,
.action-link-btn {
  display: inline-block;
  border-radius: 10px;
  padding: 10px 14px;
  background: #1e293b;
  color: #ffffff;
  text-align: center;
}

.sidebar-link:hover,
.action-link-btn:hover {
  background: #334155;
}

.active-link {
  background: #2563eb;
}

.logout-btn {
  background: #dc2626;
}

.logout-btn:hover {
  background: #b91c1c;
}

.main-content {
  padding: 26px;
}

.topbar {
  margin-bottom: 20px;
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: flex-start;
}

.topbar h2 {
  margin: 0 0 6px 0;
}

.topbar p {
  margin: 0;
  color: #64748b;
}

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

.teacher-identity {
  display: inline-block;
  padding: 10px 14px;
  background: #e2e8f0;
  border-radius: 10px;
  font-weight: 700;
}

.section-grid {
  display: grid;
  gap: 18px;
  margin-bottom: 18px;
}

.two-columns {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.summary-grid {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

.summary-card,
.panel-card,
.info-card,
.landing-card,
.auth-card {
  background: #ffffff;
  border: 1px solid #e2e8f0;
  border-radius: 18px;
  box-shadow: 0 8px 20px rgba(15, 23, 42, 0.05);
}

.summary-card {
  padding: 18px;
}

.summary-card.mini {
  min-height: 120px;
}

.summary-label {
  display: block;
  font-size: 13px;
  color: #64748b;
  margin-bottom: 8px;
}

.summary-card strong {
  font-size: 24px;
  display: block;
  word-break: break-word;
}

.panel-card {
  padding: 18px;
  margin-bottom: 18px;
}

.panel-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 14px;
}

.panel-card-header h3 {
  margin: 0;
}

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

.toolbar-row {
  display: flex;
  gap: 12px;
  margin-bottom: 14px;
}

.toolbar-row.multi {
  flex-wrap: wrap;
}

.toolbar-row > * {
  flex: 1 1 180px;
}

.preview-box,
.hint-box {
  margin-top: 14px;
  padding: 14px;
  border-radius: 12px;
  background: #eff6ff;
  border: 1px solid #bfdbfe;
}

.table-wrap {
  overflow-x: auto;
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  min-width: 1100px;
}

.data-table th,
.data-table td {
  border-bottom: 1px solid #e2e8f0;
  padding: 10px 12px;
  text-align: left;
  vertical-align: top;
}

.data-table th {
  background: #f8fafc;
  font-weight: 700;
  color: #334155;
}

.table-input {
  min-width: 140px;
}

.small-btn {
  padding: 8px 12px;
}

.card-list {
  display: grid;
  gap: 12px;
}

.card-list-block h4 {
  margin: 0 0 10px 0;
}

.info-card {
  padding: 14px;
}

.compact-list {
  margin: 8px 0 0 18px;
  padding: 0;
}

.landing-shell,
.auth-shell {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 24px;
}

.landing-card,
.auth-card {
  max-width: 1000px;
  width: 100%;
  padding: 28px;
}

.small-auth-card {
  max-width: 460px;
}

.landing-subtitle,
.muted {
  color: #64748b;
}

.landing-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
  margin-top: 20px;
}

.two-home-cards {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.landing-link-card {
  display: block;
  background: #eff6ff;
  border: 1px solid #bfdbfe;
  border-radius: 18px;
  padding: 20px;
  color: #1f2937;
}

.landing-link-card h2 {
  margin-top: 0;
}

.auth-links {
  display: flex;
  gap: 16px;
  margin-top: 16px;
  flex-wrap: wrap;
}

.status-text {
  margin: 0;
}

.status-text.bad {
  color: #b91c1c;
}

.status-text.ok {
  color: #166534;
}

.student-info-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.hamburger-btn {
  position: fixed;
  top: 14px;
  left: 14px;
  z-index: 2000;
  width: 48px;
  height: 48px;
  background: #0f172a;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  padding: 10px;
  border-radius: 12px;
}

.hamburger-btn span {
  display: block;
  width: 100%;
  height: 3px;
  background: #ffffff;
  border-radius: 999px;
}

.collapsible-sidebar {
  transform: translateX(-100%);
  position: fixed;
  top: 0;
  left: 0;
  width: 260px;
  height: 100vh;
  z-index: 1500;
  transition: transform 0.25s ease;
}

.collapsible-sidebar.sidebar-open {
  transform: translateX(0);
}

@media (min-width: 1101px) {
  .menu-shell {
    grid-template-columns: 1fr;
  }

  .main-content {
    padding-left: 88px;
  }
}

@media (max-width: 1100px) {
  .summary-grid,
  .two-columns,
  .landing-grid,
  .student-info-grid,
  .two-home-cards {
    grid-template-columns: 1fr;
  }

  .main-content {
    padding-top: 80px;
  }
}

body.sidebar-lock {
  overflow: hidden;
}

@media (max-width: 768px) {
  .menu-shell {
    display: block !important;
  }

  .main-content {
    padding-top: 92px !important;
    padding-left: 16px !important;
    padding-right: 16px !important;
  }

  .topbar {
    display: block !important;
    gap: 10px !important;
    margin-top: 0 !important;
    padding-top: 0 !important;
  }

  .topbar .topbar-right,
  .topbar-right {
    margin-top: 10px !important;
  }

  .teacher-identity {
    display: inline-flex !important;
    max-width: 100%;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
  }

  .hamburger-btn {
    position: fixed !important;
    top: 16px !important;
    left: 16px !important;
    z-index: 1300 !important;
  }

  .sidebar,
  .collapsible-sidebar {
    position: fixed !important;
    top: 0 !important;
    left: 0 !important;
    width: min(84vw, 320px) !important;
    height: 100vh !important;
    overflow-y: auto !important;
    transform: translateX(-100%) !important;
    transition: transform 0.25s ease !important;
    z-index: 1250 !important;
    padding-top: 84px !important;
  }

  .sidebar.sidebar-open,
  .collapsible-sidebar.sidebar-open {
    transform: translateX(0) !important;
  }

  .sidebar .brand,
  .collapsible-sidebar .brand {
    margin-top: 0 !important;
    padding-top: 0 !important;
  }

  .sidebar-links {
    gap: 10px !important;
  }

  .sidebar-link,
  .logout-btn {
    min-height: auto !important;
    padding: 12px 16px !important;
    font-size: 14px !important;
  }

  .summary-top-grid {
    grid-template-columns: 1fr !important;
    gap: 12px !important;
  }

  .summary-top-grid .summary-hero-card:first-child {
    padding: 12px 14px !important;
  }

  .summary-top-grid .summary-hero-card:first-child .hero-value {
    font-size: 24px !important;
  }

  .summary-top-grid .summary-hero-card:last-child {
    padding: 16px !important;
  }

  .summary-meta-grid,
  .student-info-grid,
  .two-columns,
  .section-grid {
    grid-template-columns: 1fr !important;
  }

  .summary-detail-grid {
    grid-template-columns: 1fr 1fr !important;
  }

  .buzz-button,
  #buzzButton,
  .student-buzz-button,
  .buzz-circle,
  .buzzer-button {
    width: min(78vw, 320px) !important;
    height: min(78vw, 320px) !important;
    max-width: 320px !important;
    max-height: 320px !important;
    margin: 18px auto !important;
    display: flex !important;
    align-items: center !important;
    justify-content: center !important;
    font-size: clamp(22px, 6vw, 34px) !important;
  }

  .student-buzzer-layout,
  .student-buzzer-grid,
  .buzzer-student-layout,
  .buzzer-main-grid,
  .buzzer-main,
  .student-buzzer-main {
    grid-template-columns: 1fr !important;
  }

  .panel-card,
  .summary-card {
    width: 100% !important;
    box-sizing: border-box !important;
  }
}

@media (max-width: 480px) {
  .main-content {
    padding-top: 88px !important;
  }

  .summary-detail-grid {
    grid-template-columns: 1fr !important;
  }

  .teacher-identity {
    font-size: 12px !important;
  }
}

/* ===== CENTRAL MENU SYSTEM START ===== */
.sidebar {
  justify-content: flex-start;
}

.sidebar-content {
  display: flex;
  flex-direction: column;
  gap: 12px;
  min-height: 100%;
}

.sidebar-identity {
  display: block;
  background: #1e293b;
  color: #e2e8f0;
  border: 1px solid #334155;
  border-radius: 10px;
  padding: 10px 12px;
  font-size: 14px;
  font-weight: 700;
  line-height: 1.3;
  word-break: break-word;
}

.menu-header-floating {
  position: fixed;
  top: 12px;
  left: 72px;
  z-index: 1400;
  display: none;
  flex-direction: column;
  gap: 2px;
  max-width: calc(100vw - 96px);
  padding: 12px 16px;
  border-radius: 12px;
  background: rgba(15, 23, 42, 0.98);
  color: #ffffff;
  box-shadow: 0 10px 24px rgba(15, 23, 42, 0.28);
  pointer-events: none;
}

.menu-header-floating.show {
  display: flex;
}

.menu-header-line1 {
  font-size: 18px !important;
  font-weight: 900 !important;
  line-height: 1.1;
  white-space: nowrap;
}

.menu-header-line2 {
  font-size: 12px;
  font-weight: 700;
  color: #cbd5e1;
  line-height: 1.1;
  white-space: nowrap;
}

.menu-header-line3 {
  font-size: 12px;
  font-weight: 600;
  color: #94a3b8;
  line-height: 1.1;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

@media (max-width: 768px) {
  .sidebar,
  .collapsible-sidebar {
    padding-top: 64px !important;
    padding-left: 0 !important;
    padding-right: 0 !important;
    padding-bottom: 0 !important;
    overflow: hidden !important;
  }

  .sidebar-content {
    height: 100%;
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    padding: 10px 16px 18px 16px;
    gap: 12px;
    justify-content: flex-start;
  }

  .sidebar .brand,
  .collapsible-sidebar .brand {
    display: none !important;
  }

  .sidebar-links {
    gap: 10px !important;
    margin-top: 0 !important;
    align-content: start;
  }

  .sidebar-link,
  .logout-btn {
    min-height: 44px !important;
    padding: 12px 16px !important;
    font-size: 14px !important;
  }
}

@media (min-width: 769px) {
  .menu-header-floating {
  position: fixed;
  top: 12px;
  left: 72px;
  z-index: 1400;
  display: none;
  flex-direction: column;
  gap: 2px;
  max-width: calc(100vw - 96px);
  padding: 12px 16px;
  border-radius: 12px;
  background: rgba(15, 23, 42, 0.98);
  color: #ffffff;
  box-shadow: 0 10px 24px rgba(15, 23, 42, 0.28);
  pointer-events: none;
}
}
/* ===== CENTRAL MENU SYSTEM END ===== */

/* ===== SIDEBAR CLEAN FINAL START ===== */
@media (max-width: 768px) {
  .sidebar .brand,
  .collapsible-sidebar .brand {
    display: block !important;
    margin: 0 !important;
    padding: 0 !important;
    min-height: auto !important;
  }

  .sidebar .brand h1,
  .collapsible-sidebar .brand h1 {
    margin: 0 0 4px 0 !important;
    font-size: 24px !important;
    line-height: 1.1 !important;
    white-space: nowrap !important;
  }

  .sidebar .brand p,
  .collapsible-sidebar .brand p {
    margin: 0 !important;
    font-size: 16px !important;
    line-height: 1.1 !important;
    color: #cbd5e1 !important;
    white-space: nowrap !important;
  }

  .sidebar-content {
    padding: 20px 20px 18px 20px !important;
    gap: 20px !important;
  }

  .sidebar-link,
  .logout-btn {
    display: block !important;
    width: 100% !important;
    border-radius: 14px !important;
    padding: 14px 16px !important;
    text-align: center !important;
    font-weight: 700 !important;
    color: #ffffff !important;
  }

  .sidebar-link {
    background: #1e293b !important;
  }

  .sidebar-link.active-link {
    background: #2563eb !important;
  }

  .logout-btn {
    background: #dc2626 !important;
  }
}
/* ===== SIDEBAR CLEAN FINAL END ===== */

/* ===== MENU MOBILE FINAL CLEAN START ===== */
@media (max-width: 768px) {
  .hamburger-btn {
    position: fixed !important;
    top: 16px !important;
    left: 16px !important;
    z-index: 2400 !important;
  }

  .sidebar,
  .collapsible-sidebar {
    position: fixed !important;
    top: 0 !important;
    left: 0 !important;
    width: min(84vw, 320px) !important;
    height: 100vh !important;
    transform: translateX(-100%) !important;
    transition: transform 0.25s ease !important;
    z-index: 2200 !important;
    background: #0f172a !important;
    overflow-y: auto !important;
    padding: 18px 20px !important;
  }

  .sidebar.sidebar-open,
  .collapsible-sidebar.sidebar-open {
    transform: translateX(0) !important;
  }

  .sidebar-content {
    padding: 0 !important;
    gap: 20px !important;
  }

  .sidebar .brand,
  .collapsible-sidebar .brand {
    display: block !important;
    margin: 0 !important;
    padding: 0 !important;
  }

  .sidebar .brand h1,
  .collapsible-sidebar .brand h1 {
    margin: 0 0 4px 0 !important;
    padding: 0 !important;
    font-size: 24px !important;
    line-height: 1.1 !important;
    color: #ffffff !important;
    white-space: nowrap !important;
  }

  .sidebar .brand p,
  .collapsible-sidebar .brand p {
    margin: 0 !important;
    padding: 0 !important;
    font-size: 16px !important;
    line-height: 1.1 !important;
    color: #cbd5e1 !important;
    white-space: nowrap !important;
  }

  .sidebar-identity {
    margin-top: 4px !important;
  }

  .sidebar-links {
    display: grid !important;
    gap: 14px !important;
    margin-top: 12px !important;
  }

  .sidebar-link,
  .logout-btn {
    display: block !important;
    width: 100% !important;
    border-radius: 14px !important;
    padding: 14px 16px !important;
    text-align: center !important;
    font-weight: 700 !important;
    color: #ffffff !important;
  }

  .sidebar-link {
    background: #1e293b !important;
  }

  .sidebar-link.active-link {
    background: #2563eb !important;
  }

  .logout-btn {
    background: #dc2626 !important;
  }

  .menu-header-floating {
    display: none !important;
  }
}
/* ===== MENU MOBILE FINAL CLEAN END ===== */