:root {
  --brand-primary: #667eea;
  --brand-secondary: #764ba2;
  --brand-dark: #4a5568;
  --surface-strong: rgba(255, 255, 255, 0.95);
  --surface-soft: rgba(255, 255, 255, 0.85);
  --shadow-soft: 0 2px 20px rgba(0, 0, 0, 0.1);
}

html,
body {
  height: 100%;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.app-main {
  flex: 1 1 auto;
  display: flex;
  flex-direction: column;
}

.app-header {
  background: var(--surface-strong);
  backdrop-filter: blur(10px);
  box-shadow: var(--shadow-soft);
  padding: 1rem 2rem;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem 2rem;
  position: sticky;
  top: 0;
  z-index: 100;
}

.app-brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.app-brand h1,
.app-brand a,
.app-brand span {
  margin: 0;
  font-size: 1.65rem;
  font-weight: 600;
  color: var(--brand-dark);
  text-decoration: none;
}

.app-brand small {
  display: block;
  font-size: 0.9rem;
  font-weight: 500;
  color: rgba(74, 85, 104, 0.78);
  margin-top: 0.2rem;
}

.app-nav {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem;
}

.app-nav a,
.app-nav button {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.55rem 1.1rem;
  border-radius: 999px;
  font-weight: 600;
  text-decoration: none;
  border: none;
  cursor: pointer;
  background: linear-gradient(45deg, var(--brand-primary), var(--brand-secondary));
  color: #ffffff;
  box-shadow: 0 5px 15px rgba(102, 126, 234, 0.3);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.app-nav a:hover,
.app-nav button:hover,
.app-nav a:focus-visible,
.app-nav button:focus-visible {
  transform: translateY(-2px);
  box-shadow: 0 8px 18px rgba(102, 126, 234, 0.35);
}

.app-nav a.active {
  outline: 2px solid rgba(255, 255, 255, 0.8);
  outline-offset: -3px;
}

.app-nav .logout-link {
  background: linear-gradient(45deg, #ff6b6b, #ee5a24);
  box-shadow: 0 5px 15px rgba(238, 90, 36, 0.35);
}

.app-nav .logout-link:hover,
.app-nav .logout-link:focus-visible {
  box-shadow: 0 8px 18px rgba(238, 90, 36, 0.4);
}

.app-nav .logout-form {
  margin: 0;
}

.app-nav .logout-form button {
  background: linear-gradient(45deg, #ff6b6b, #ee5a24);
  box-shadow: 0 5px 15px rgba(238, 90, 36, 0.35);
}

.app-nav .logout-form button:hover,
.app-nav .logout-form button:focus-visible {
  box-shadow: 0 8px 18px rgba(238, 90, 36, 0.4);
}

.app-footer {
  margin-top: auto;
  padding: 1rem;
  text-align: center;
  font-size: 0.9rem;
  background: var(--surface-soft);
  backdrop-filter: blur(10px);
  color: var(--brand-dark);
}

@media (max-width: 680px) {
  .app-header {
    padding: 1rem 1.25rem;
  }

  .app-brand h1,
  .app-brand a,
  .app-brand span {
    font-size: 1.35rem;
  }

  .app-nav a,
  .app-nav button {
    font-size: 0.95rem;
    padding: 0.5rem 0.9rem;
  }
}