<style>
/* ========================================
   ZD LEARNING — Dashboard Layout
   Phase 1 : Squelette principal
   Convention : BEM strict, préfixe zd-
   ======================================== */

:root {
  /* — Couleurs principales — */
  --zd-color-primary:        #2563EB;
  --zd-color-primary-hover:  #1D4ED8;
  --zd-color-primary-light:  #EFF6FF;
  --zd-color-accent-gold:    #F59E0B;
  --zd-color-accent-gold-bg: #FFFBEB;

  /* — Neutres — */
  --zd-color-white:          #FFFFFF;
  --zd-color-bg:             #F9FAFB;
  --zd-color-border:         #E5E7EB;
  --zd-color-text-primary:   #111827;
  --zd-color-text-secondary: #6B7280;
  --zd-color-text-muted:     #9CA3AF;
  --zd-color-sidebar-bg:     #FFFFFF;
  --zd-color-topbar-bg:      #FFFFFF;
  --zd-color-overlay:        rgba(17, 24, 39, 0.45);

  /* — Espacements — */
  --zd-space-4:   0.25rem;
  --zd-space-8:   0.5rem;
  --zd-space-12:  0.75rem;
  --zd-space-16:  1rem;
  --zd-space-20:  1.25rem;
  --zd-space-24:  1.5rem;
  --zd-space-32:  2rem;
  --zd-space-40:  2.5rem;

  /* — Dimensions — */
  --zd-sidebar-width:   260px;
  --zd-topbar-height:   64px;
  --zd-avatar-size:     38px;

  /* — Rayons — */
  --zd-radius-sm:  6px;
  --zd-radius-md:  10px;
  --zd-radius-lg:  14px;
  --zd-radius-pill: 9999px;

  /* — Ombres — */
  --zd-shadow-sm:   0 1px 2px rgba(0,0,0,0.05);
  --zd-shadow-md:   0 4px 12px rgba(0,0,0,0.08);
  --zd-shadow-lg:   0 10px 30px rgba(0,0,0,0.12);
  --zd-shadow-sidebar: 2px 0 16px rgba(0,0,0,0.06);

  /* — Transitions — */
  --zd-transition-fast:    180ms ease;
  --zd-transition-base:    300ms ease;
  --zd-transition-smooth:  300ms cubic-bezier(0.4, 0, 0.2, 1);

  /* — Typographie — */
  --zd-font-family: 'Segoe UI', -apple-system, BlinkMacSystemFont, sans-serif;
  --zd-font-size-xs:   0.75rem;
  --zd-font-size-sm:   0.8125rem;
  --zd-font-size-base: 0.9375rem;
  --zd-font-size-md:   1.0625rem;
  --zd-font-size-lg:   1.25rem;
  --zd-font-weight-normal:   400;
  --zd-font-weight-medium:   500;
  --zd-font-weight-semibold: 600;
  --zd-font-weight-bold:     700;
}

/* ——— Reset ciblé ——— */
.zd-dashboard *,
.zd-dashboard *::before,
.zd-dashboard *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

.zd-dashboard {
  display: flex;
  min-height: 100vh;
  font-family: var(--zd-font-family);
  color: var(--zd-color-text-primary);
  background-color: var(--zd-color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ======================
   OVERLAY (mobile)
   ====================== */
.zd-overlay {
  position: fixed;
  inset: 0;
  z-index: 998;
  background-color: var(--zd-color-overlay);
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--zd-transition-base), visibility var(--zd-transition-base);
}

.zd-overlay--visible {
  opacity: 1;
  visibility: visible;
}

/* ======================
   SIDEBAR
   ====================== */
.zd-sidebar {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 999;
  display: flex;
  flex-direction: column;
  width: var(--zd-sidebar-width);
  height: 100vh;
  height: 100dvh;
  background-color: var(--zd-color-sidebar-bg);
  border-right: 1px solid var(--zd-color-border);
  box-shadow: var(--zd-shadow-sidebar);
  transform: translateX(-100%);
  transition: transform var(--zd-transition-smooth);
  overflow-y: auto;
  overscroll-behavior: contain;
}

.zd-sidebar--open {
  transform: translateX(0);
}

/* — Logo — */
.zd-sidebar__header {
  display: flex;
  align-items: center;
  gap: var(--zd-space-12);
  padding: var(--zd-space-24) var(--zd-space-24) var(--zd-space-20);
}

.zd-sidebar__logo-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--zd-radius-md);
  background: linear-gradient(135deg, var(--zd-color-primary), #3B82F6);
  flex-shrink: 0;
}

.zd-sidebar__logo-icon svg {
  width: 20px;
  height: 20px;
  fill: var(--zd-color-white);
}

.zd-sidebar__logo-text {
  font-size: var(--zd-font-size-lg);
  font-weight: var(--zd-font-weight-bold);
  color: var(--zd-color-text-primary);
  letter-spacing: -0.02em;
  line-height: 1;
}

.zd-sidebar__logo-text span {
  color: var(--zd-color-primary);
}

/* — Bouton fermer (mobile) — */
.zd-sidebar__close {
  display: flex;
  align-items: center;
  justify-content: center;
  position: absolute;
  top: var(--zd-space-16);
  right: var(--zd-space-16);
  width: 32px;
  height: 32px;
  border: none;
  border-radius: var(--zd-radius-sm);
  background: transparent;
  color: var(--zd-color-text-muted);
  cursor: pointer;
  transition: background-color var(--zd-transition-fast), color var(--zd-transition-fast);
}

.zd-sidebar__close:hover,
.zd-sidebar__close:focus-visible {
  background-color: var(--zd-color-bg);
  color: var(--zd-color-text-primary);
}

.zd-sidebar__close:focus-visible {
  outline: 2px solid var(--zd-color-primary);
  outline-offset: 2px;
}

.zd-sidebar__close svg {
  width: 18px;
  height: 18px;
  stroke: currentColor;
  stroke-width: 2;
  fill: none;
}

/* — Navigation — */
.zd-sidebar__nav {
  flex: 1;
  padding: var(--zd-space-8) var(--zd-space-12);
}

.zd-sidebar__nav-label {
  display: block;
  padding: var(--zd-space-8) var(--zd-space-12);
  font-size: var(--zd-font-size-xs);
  font-weight: var(--zd-font-weight-semibold);
  color: var(--zd-color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.zd-sidebar__menu {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--zd-space-4);
}

.zd-sidebar__menu-link {
  display: flex;
  align-items: center;
  gap: var(--zd-space-12);
  padding: var(--zd-space-12) var(--zd-space-16);
  border-radius: var(--zd-radius-md);
  font-size: var(--zd-font-size-sm);
  font-weight: var(--zd-font-weight-medium);
  color: var(--zd-color-text-secondary);
  text-decoration: none;
  transition: background-color var(--zd-transition-fast), color var(--zd-transition-fast);
  cursor: pointer;
}

.zd-sidebar__menu-link:hover {
  background-color: var(--zd-color-bg);
  color: var(--zd-color-text-primary);
}

.zd-sidebar__menu-link:focus-visible {
  outline: 2px solid var(--zd-color-primary);
  outline-offset: -2px;
  border-radius: var(--zd-radius-md);
}

.zd-sidebar__menu-link--active {
  background-color: var(--zd-color-primary-light);
  color: var(--zd-color-primary);
  font-weight: var(--zd-font-weight-semibold);
}

.zd-sidebar__menu-link--active:hover {
  background-color: var(--zd-color-primary-light);
  color: var(--zd-color-primary);
}

.zd-sidebar__menu-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 22px;
  height: 22px;
  flex-shrink: 0;
}

.zd-sidebar__menu-icon svg {
  width: 20px;
  height: 20px;
  stroke: currentColor;
  stroke-width: 1.8;
  fill: none;
  stroke-linecap: round;
  stroke-linejoin: round;
}

/* — Footer sidebar — */
.zd-sidebar__footer {
  padding: var(--zd-space-16) var(--zd-space-24);
  border-top: 1px solid var(--zd-color-border);
}

.zd-sidebar__footer-text {
  font-size: var(--zd-font-size-xs);
  color: var(--zd-color-text-muted);
}

/* ======================
   MAIN WRAPPER
   ====================== */
.zd-main-wrapper {
  display: flex;
  flex-direction: column;
  flex: 1;
  min-height: 100vh;
  min-height: 100dvh;
  margin-left: 0;
  transition: margin-left var(--zd-transition-smooth);
}

/* ======================
   TOPBAR
   ====================== */
.zd-topbar {
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  height: var(--zd-topbar-height);
  padding: 0 var(--zd-space-16);
  background-color: var(--zd-color-topbar-bg);
  border-bottom: 1px solid var(--zd-color-border);
  box-shadow: var(--zd-shadow-sm);
  gap: var(--zd-space-12);
}

/* — Hamburger — */
.zd-topbar__hamburger {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border: none;
  border-radius: var(--zd-radius-sm);
  background: transparent;
  color: var(--zd-color-text-primary);
  cursor: pointer;
  transition: background-color var(--zd-transition-fast);
  flex-shrink: 0;
}

.zd-topbar__hamburger:hover,
.zd-topbar__hamburger:focus-visible {
  background-color: var(--zd-color-bg);
}

.zd-topbar__hamburger:focus-visible {
  outline: 2px solid var(--zd-color-primary);
  outline-offset: 2px;
}

.zd-topbar__hamburger svg {
  width: 22px;
  height: 22px;
  stroke: currentColor;
  stroke-width: 2;
  fill: none;
  stroke-linecap: round;
}

/* — Welcome — */
.zd-topbar__welcome {
  flex: 1;
  min-width: 0;
}

.zd-topbar__welcome-label {
  display: block;
  font-size: var(--zd-font-size-xs);
  color: var(--zd-color-text-muted);
  line-height: 1.2;
}

.zd-topbar__welcome-name {
  display: block;
  font-size: var(--zd-font-size-base);
  font-weight: var(--zd-font-weight-semibold);
  color: var(--zd-color-text-primary);
  line-height: 1.3;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* — Wallet Pill — */
.zd-topbar__wallet {
  display: flex;
  align-items: center;
  gap: var(--zd-space-8);
  padding: var(--zd-space-8) var(--zd-space-16);
  border-radius: var(--zd-radius-pill);
  background-color: var(--zd-color-accent-gold-bg);
  border: 1px solid rgba(245, 158, 11, 0.2);
  font-size: var(--zd-font-size-sm);
  font-weight: var(--zd-font-weight-semibold);
  color: #92400E;
  white-space: nowrap;
  flex-shrink: 0;
  transition: box-shadow var(--zd-transition-fast);
  cursor: default;
}

.zd-topbar__wallet:hover {
  box-shadow: 0 0 0 3px rgba(245, 158, 11, 0.12);
}

.zd-topbar__wallet-icon {
  font-size: var(--zd-font-size-base);
  line-height: 1;
}

/* — Avatar — */
.zd-topbar__avatar {
  width: var(--zd-avatar-size);
  height: var(--zd-avatar-size);
  border-radius: var(--zd-radius-pill);
  background: linear-gradient(135deg, var(--zd-color-primary), #818CF8);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--zd-font-size-sm);
  font-weight: var(--zd-font-weight-bold);
  color: var(--zd-color-white);
  flex-shrink: 0;
  cursor: pointer;
  transition: box-shadow var(--zd-transition-fast);
  text-transform: uppercase;
}

.zd-topbar__avatar:hover {
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.18);
}

/* ======================
   MAIN CONTENT
   ====================== */
.zd-content {
  flex: 1;
  padding: var(--zd-space-20);
  background-color: var(--zd-color-bg);
}

.zd-content__placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 50vh;
  border: 2px dashed var(--zd-color-border);
  border-radius: var(--zd-radius-lg);
  background-color: var(--zd-color-white);
}

.zd-content__placeholder-icon {
  width: 48px;
  height: 48px;
  margin-bottom: var(--zd-space-16);
  color: var(--zd-color-text-muted);
}

.zd-content__placeholder-icon svg {
  width: 100%;
  height: 100%;
  stroke: currentColor;
  stroke-width: 1.2;
  fill: none;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.zd-content__placeholder-text {
  font-size: var(--zd-font-size-sm);
  color: var(--zd-color-text-muted);
  font-weight: var(--zd-font-weight-medium);
}

/* ======================
   RESPONSIVE — Desktop ≥ 1024px
   ====================== */
@media (min-width: 1024px) {
  .zd-sidebar {
    transform: translateX(0);
  }

  .zd-sidebar__close {
    display: none;
  }

  .zd-overlay {
    display: none;
  }

  .zd-main-wrapper {
    margin-left: var(--zd-sidebar-width);
  }

  .zd-topbar {
    padding: 0 var(--zd-space-32);
  }

  .zd-topbar__hamburger {
    display: none;
  }

  .zd-content {
    padding: var(--zd-space-32);
  }
}

.zd-dashboard-cards {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
  padding: 24px;
}

.zd-card {
  background: #ffffff;
  border: 1px solid #e5e7eb;
  border-radius: 16px;
  padding: 20px;
  box-shadow: 0 8px 24px rgba(15, 23, 42, 0.04);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.zd-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 30px rgba(15, 23, 42, 0.08);
}

.zd-card h3 {
  margin: 0 0 10px;
  font-size: 15px;
  font-weight: 600;
  color: #6b7280;
}

.zd-card-number {
  margin: 0;
  font-size: 32px;
  font-weight: 700;
  color: #111827;
  line-height: 1;
}

@media (min-width: 768px) {
  .zd-dashboard-cards {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1200px) {
  .zd-dashboard-cards {
    grid-template-columns: repeat(4, 1fr);
  }
}