:root {
    --auth-bg: #0b1220;
    --auth-panel: #111827;
    --auth-card: #ffffff;
    --auth-accent: #6366f1;
    --auth-accent-2: #22d3ee;
    --auth-text: #0f172a;
    --auth-muted: #64748b;
    --auth-border: #e2e8f0;
    --auth-radius: 16px;
    --auth-shadow: 0 25px 50px -12px rgba(15, 23, 42, 0.35);
    --auth-font: "DM Sans", system-ui, -apple-system, "Segoe UI", Roboto, Arial, sans-serif;
  }
  
  *,
  *::before,
  *::after {
    box-sizing: border-box;
  }
  
  html {
    scroll-behavior: smooth;
  }
  
  body.auth-body {
    margin: 0;
    min-height: 100vh;
    font-family: var(--auth-font);
    color: var(--auth-text);
    background: radial-gradient(1200px 600px at 10% -10%, rgba(99, 102, 241, 0.35), transparent),
      radial-gradient(900px 500px at 100% 0%, rgba(34, 211, 238, 0.22), transparent),
      linear-gradient(165deg, var(--auth-bg) 0%, #0f172a 45%, #020617 100%);
  }
  
  .auth-shell {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
  }
  
  @media (min-width: 992px) {
    .auth-shell {
      flex-direction: row;
    }
  }
  
  .auth-hero {
    position: relative;
    flex: 1;
    min-height: 220px;
    padding: clamp(1.5rem, 4vw, 3rem);
    display: flex;
    align-items: flex-end;
    color: #f8fafc;
    overflow: hidden;
  }
  
  .auth-hero::before {
    content: "";
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, rgba(15, 23, 42, 0.2), rgba(15, 23, 42, 0.85)),
      url("https://images.unsplash.com/photo-1521791136064-7986c2920216?auto=format&fit=crop&w=1600&q=80")
        center / cover no-repeat;
    transform: scale(1.02);
  }
  
  .auth-hero--register::before {
    background: linear-gradient(135deg, rgba(15, 23, 42, 0.25), rgba(15, 23, 42, 0.88)),
      url("https://images.unsplash.com/photo-1560179707-f14e90ef3623?auto=format&fit=crop&w=1600&q=80") center / cover no-repeat;
  }
  
  .auth-hero-inner {
    position: relative;
    z-index: 1;
    max-width: 520px;
  }
  
  .auth-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.35rem 0.75rem;
    border-radius: 999px;
    font-size: 0.75rem;
    letter-spacing: 0.04em;
    text-transform: uppercase;
    background: rgba(248, 250, 252, 0.12);
    border: 1px solid rgba(248, 250, 252, 0.18);
    margin-bottom: 1rem;
  }
  
  .auth-hero h1 {
    font-size: clamp(1.75rem, 3vw, 2.75rem);
    font-weight: 700;
    line-height: 1.15;
    margin: 0 0 0.75rem;
  }
  
  .auth-hero p {
    margin: 0;
    font-size: clamp(1rem, 1.2vw, 1.125rem);
    color: rgba(248, 250, 252, 0.85);
    line-height: 1.6;
  }
  
  .auth-panel {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: clamp(1.25rem, 3vw, 2.5rem);
  }
  
  .auth-card {
    width: 100%;
    max-width: 420px;
    background: var(--auth-card);
    border-radius: var(--auth-radius);
    box-shadow: var(--auth-shadow);
    border: 1px solid rgba(148, 163, 184, 0.18);
    padding: clamp(1.5rem, 3vw, 2.25rem);
  }
  
  .auth-card.compact {
    max-width: 400px;
  }
  
  .auth-brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 1.5rem;
  }
  
  .auth-brand-mark {
    width: 44px;
    height: 44px;
    border-radius: 12px;
    display: grid;
    place-items: center;
    color: #fff;
    background: linear-gradient(135deg, var(--auth-accent), var(--auth-accent-2));
    box-shadow: 0 10px 25px rgba(99, 102, 241, 0.35);
  }
  
  .auth-brand h2 {
    margin: 0;
    font-size: 1.35rem;
    font-weight: 700;
  }
  
  .auth-brand span {
    display: block;
    font-size: 0.875rem;
    color: var(--auth-muted);
    font-weight: 500;
  }
  
  .auth-divider {
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--auth-border), transparent);
    margin: 1.25rem 0 1.5rem;
  }
  
  .auth-label {
    font-size: 0.8125rem;
    font-weight: 600;
    color: var(--auth-muted);
    margin-bottom: 0.35rem;
  }
  
  .auth-input-group .input-group-text {
    background: #f8fafc;
    border-color: var(--auth-border);
    color: #475569;
  }
  
  .auth-input-group .form-control,
  .auth-input-group .form-select {
    border-color: var(--auth-border);
    padding-top: 0.65rem;
    padding-bottom: 0.65rem;
  }
  
  .auth-input-group .form-control:focus,
  .auth-input-group .form-select:focus {
    border-color: rgba(99, 102, 241, 0.55);
    box-shadow: 0 0 0 0.2rem rgba(99, 102, 241, 0.15);
  }
  
  .btn-auth-primary {
    --bs-btn-bg: var(--auth-accent);
    --bs-btn-border-color: var(--auth-accent);
    --bs-btn-hover-bg: #4f46e5;
    --bs-btn-hover-border-color: #4f46e5;
    --bs-btn-active-bg: #4338ca;
    --bs-btn-active-border-color: #4338ca;
    font-weight: 600;
    padding-top: 0.7rem;
    padding-bottom: 0.7rem;
    border-radius: 12px;
  }
  
  .btn-auth-ghost {
    border-radius: 12px;
    font-weight: 600;
  }
  
  .auth-foot {
    margin-top: 1.5rem;
    text-align: center;
    font-size: 0.9rem;
    color: var(--auth-muted);
  }
  
  .auth-foot a {
    color: var(--auth-accent);
    font-weight: 600;
    text-decoration: none;
  }
  
  .auth-foot a:hover {
    text-decoration: underline;
  }
  
  .auth-alert {
    border-radius: 12px;
    font-size: 0.9rem;
  }
  
  .auth-standalone {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1.25rem;
  }
  
  .auth-standalone .auth-card {
    animation: authFade 0.45s ease-out;
  }
  
  @keyframes authFade {
    from {
      opacity: 0;
      transform: translateY(10px);
    }
    to {
      opacity: 1;
      transform: translateY(0);
    }
  }
  
  @media (max-width: 991.98px) {
    .auth-hero {
      min-height: 200px;
    }
  }