Gradient/Color Transitions(그라디언트/색상 전환), Grayscale Dashboard, Navigation Bar(그레이스케일 대시보드, 네비게이션 바)

<nav class="bg-white shadow-lg transition-colors duration-300 dark:bg-gray-900 border-b border-gray-200 dark:border-gray-800">
  <div class="mx-auto px-4 sm:px-6 lg:px-8">
    <div class="flex items-center justify-between h-16">
      <div class="flex items-center">
        <div class="flex-shrink-0">
          <a href="#" class="text-2xl font-bold bg-gradient-to-r from-gray-700 to-black text-transparent bg-clip-text dark:from-gray-300 dark:to-gray-100 dark:bg-opacity-75 transition-all duration-300">Dashboard</a>
        </div>
        <div class="hidden md:block">
          <div class="ml-10 flex items-baseline space-x-4">
            <a href="#" class="text-gray-600 dark:text-gray-300 hover:bg-gray-100 hover:text-gray-800 dark:hover:bg-gray-700 dark:hover:text-white px-3 py-2 rounded-md text-sm font-medium transition-colors duration-200">Overview</a>
            <a href="#" class="text-gray-600 dark:text-gray-300 hover:bg-gray-100 hover:text-gray-800 dark:hover:bg-gray-700 dark:hover:text-white px-3 py-2 rounded-md text-sm font-medium transition-colors duration-200">Analytics</a>
            <a href="#" class="text-gray-600 dark:text-gray-300 hover:bg-gray-100 hover:text-gray-800 dark:hover:bg-gray-700 dark:hover:text-white px-3 py-2 rounded-md text-sm font-medium transition-colors duration-200">Reports</a>
            <a href="#" class="text-gray-600 dark:text-gray-300 hover:bg-gray-100 hover:text-gray-800 dark:hover:bg-gray-700 dark:hover:text-white px-3 py-2 rounded-md text-sm font-medium transition-colors duration-200">Settings</a>
          </div>
        </div>
      </div>

      <div class="hidden md:block">
        <div class="ml-4 flex items-center md:ml-6">
          <button type="button" class="relative p-1 rounded-full text-gray-400 hover:text-gray-900 focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-gray-500 dark:text-gray-300 dark:hover:text-white dark:focus:ring-offset-gray-800 dark:focus:ring-gray-400 transition-colors duration-200">
            <span class="absolute -inset-1.5"></span>
            <span class="sr-only">View notifications</span>
            <svg class="h-6 w-6" fill="none" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor" aria-hidden="true">
              <path stroke-linecap="round" stroke-linejoin="round" d="M14.857 17.082a23.848 23.848 0 005.454-1.31A8.967 8.967 0 0118 9.75v-.7V9A6 6 0 006 9v.75a8.967 8.967 0 01-2.312 6.022c1.733.64 3.56 1.04 5.455 1.31m5.8-3.003V12m0 8.25v-1.5m0-1.5V12m0 0a2.25 2.25 0 00-2.25 2.25V18a2.25 2.25 0 002.25 2.25h.75m0-4.5h-.75m-.75 0h-.75m-3.93-1.071c.42-.872 1.05-1.56 1.79-2.07c.74-.51 1.57-.79 2.44-.79h.75m0 0v-2.25m0 2.25h.75m0 0c.974 0 1.905-.275 2.722-.764m0 0A6.5 6.5 0 0012 2.25 6.5 6.5 0 006 8.25c0 1.62-.516 3.12-1.39 4.34m0 0L4.5 14.25m15 0a.75.75 0 00.75-.75L21 12.75l-.75-1.5a.75.75 0 00-.75-.75H3.75a.75.75 0 00-.75.75L3 12.75l.75 1.5a.75.75 0 00.75.75h15z" />
            </svg>
          </button>

          <div class="relative ml-3 group">
            <button type="button" class="relative flex max-w-xs items-center rounded-full bg-white dark:bg-gray-800 text-sm focus:outline-none focus:ring-2 focus:ring-gray-500 focus:ring-offset-2 dark:focus:ring-offset-gray-800 dark:focus:ring-gray-400 transition-colors duration-200" id="user-menu-button" aria-expanded="false" aria-haspopup="true">
              <span class="absolute -inset-1.5"></span>
              <span class="sr-only">Open user menu</span>
              <img class="h-8 w-8 rounded-full" src="https://randomuser.me/api/portraits/men/32.jpg" alt="User Avatar">
            </button>
            <div class="absolute right-0 z-10 mt-2 w-48 origin-top-right rounded-md bg-white dark:bg-gray-800 py-1 shadow-lg ring-1 ring-black ring-opacity-5 focus:outline-none opacity-0 invisible group-hover:opacity-100 group-hover:visible transition-all duration-300 scale-95 group-hover:scale-100" role="menu" aria-orientation="vertical" aria-labelledby="user-menu-button" tabindex="-1">
              <a href="#" class="block px-4 py-2 text-sm text-gray-700 dark:text-gray-300 hover:bg-gray-100 dark:hover:bg-gray-700 transition-colors duration-200" role="menuitem" tabindex="-1" id="user-menu-item-0">Your Profile</a>
              <a href="#" class="block px-4 py-2 text-sm text-gray-700 dark:text-gray-300 hover:bg-gray-100 dark:hover:bg-gray-700 transition-colors duration-200" role="menuitem" tabindex="-1" id="user-menu-item-1">Settings</a>
              <a href="#" class="block px-4 py-2 text-sm text-gray-700 dark:text-gray-300 hover:bg-gray-100 dark:hover:bg-gray-700 transition-colors duration-200" role="menuitem" tabindex="-1" id="user-menu-item-2">Sign out</a>
            </div>
          </div>

          <!-- Dark Mode Toggle (Conceptual - requires JS for functionality) -->
          <button type="button" class="ml-4 p-1 rounded-full text-gray-400 hover:text-gray-900 focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-gray-500 dark:text-gray-300 dark:hover:text-white dark:focus:ring-offset-gray-800 dark:focus:ring-gray-400 transition-colors duration-200" aria-label="Toggle dark mode">
            <svg class="h-6 w-6 dark:hidden" fill="none" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor">
              <path stroke-linecap="round" stroke-linejoin="round" d="M21.752 15.002A9.718 9.718 0 0118 15.75c-1.033 0-2.049-.154-3-.443m-4.321 4.75A9.704 9.704 0 0012 21.75c1.033 0 2.049-.154 3-.443m-4.321-4.75a9.704 9.704 0 01-3-.443m-4.321-4.75a9.704 9.704 0 01-3-.443M2.25 12A9.704 9.704 0 015.25 11.25c1.033 0 2.049.154 3 .443m4.321-4.75a9.704 9.704 0 013-.443m4.321-4.75a9.704 9.704 0 013-.443" />
              <path stroke-linecap="round" stroke-linejoin="round" d="M12 21.75c1.033 0 2.049-.154 3-.443m-4.321-4.75a9.704 9.704 0 01-3-.443M2.25 12A9.704 9.704 0 015.25 11.25c1.033 0 2.049.154 3 .443m4.321-4.75a9.704 9.704 0 013-.443m4.321-4.75a9.704 9.704 0 013-.443m-4.321-4.75a9.704 9.704 0 01-3-.443M21 12.75a9.704 9.704 0 01-3 .443m-4.321 4.75a9.704 9.704 0 01-3-.443" />
              <circle cx="12" cy="12" r="8" stroke="currentColor" stroke-fill="none" />
              <path stroke-linecap="round" stroke-linejoin="round" d="M7.5 7.5l9 9M7.5 16.5l9-9" />
            </svg>
            <svg class="h-6 w-6 hidden dark:block" fill="none" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor">
              <path stroke-linecap="round" stroke-linejoin="round" d="M21.752 15.002A9.718 9.718 0 0118 15.75c-1.033 0-2.049-.154-3-.443m-4.321 4.75A9.704 9.704 0 0012 21.75c1.033 0 2.049-.154 3-.443m-4.321-4.75a9.704 9.704 0 01-3-.443m-4.321-4.75a9.704 9.704 0 01-3-.443M2.25 12A9.704 9.704 0 015.25 11.25c1.033 0 2.049.154 3 .443m4.321-4.75a9.704 9.704 0 013-.443m4.321-4.75a9.704 9.704 0 013-.443m-4.321-4.75a9.704 9.704 0 01-3-.443M21 12.75a9.704 9.704 0 01-3 .443m-4.321 4.75a9.704 9.704 0 01-3-.443" />
              <path stroke-linecap="round" stroke-linejoin="round" d="M12 3v18M3 12h18A9.704 9.704 0 0112 2.25c-1.033 0-2.049.154-3 .443M21.75 3.75v16.5A.75.75 0 0121 21.75H3a.75.75 0 01-.75-.75V3.75a.75.75 0 01.75-.75h18z" />
            </svg>
          </button>
        </div>
      </div>

      <div class="-mr-2 flex md:hidden">
        <button type="button" class="relative inline-flex items-center justify-center rounded-md p-2 text-gray-400 hover:bg-gray-100 hover:text-gray-900 focus:outline-none focus:ring-2 focus:ring-inset focus:ring-gray-500 dark:text-gray-300 dark:hover:bg-gray-700 dark:hover:text-white dark:focus:ring-gray-400 transition-colors duration-200" aria-controls="mobile-menu" aria-expanded="false">
          <span class="absolute -inset-0.5"></span>
          <span class="sr-only">Open main menu</span>
          <svg class="block h-6 w-6" fill="none" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor" aria-hidden="true">
            <path stroke-linecap="round" stroke-linejoin="round" d="M3.75 6.75h16.5M3.75 12h16.5m-16.5 5.25h16.5" />
          </svg>
          <svg class="hidden h-6 w-6" fill="none" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor" aria-hidden="true">
            <path stroke-linecap="round" stroke-linejoin="round" d="M6 18L18 6M6 6l12 12" />
          </svg>
        </button>
      </div>
    </div>
  </div>

  <!-- Mobile menu, show/hide based on menu state. -->
  <div class="md:hidden hidden" id="mobile-menu">
    <div class="space-y-1 px-2 pb-3 pt-2 sm:px-3">
      <a href="#" class="text-gray-600 dark:text-gray-300 hover:bg-gray-100 hover:text-gray-800 dark:hover:bg-gray-700 dark:hover:text-white block px-3 py-2 rounded-md text-base font-medium transition-colors duration-200">Overview</a>
      <a href="#" class="text-gray-600 dark:text-gray-300 hover:bg-gray-100 hover:text-gray-800 dark:hover:bg-gray-700 dark:hover:text-white block px-3 py-2 rounded-md text-base font-medium transition-colors duration-200">Analytics</a>
      <a href="#" class="text-gray-600 dark:text-gray-300 hover:bg-gray-100 hover:text-gray-800 dark:hover:bg-gray-700 dark:hover:text-white block px-3 py-2 rounded-md text-base font-medium transition-colors duration-200">Reports</a>
      <a href="#" class="text-gray-600 dark:text-gray-300 hover:bg-gray-100 hover:text-gray-800 dark:hover:bg-gray-700 dark:hover:text-white block px-3 py-2 rounded-md text-base font-medium transition-colors duration-200">Settings</a>
    </div>
    <div class="border-t border-gray-200 pb-3 pt-4 dark:border-gray-700">
      <div class="flex items-center px-5">
        <div class="flex-shrink-0">
          <img class="h-10 w-10 rounded-full" src="https://randomuser.me/api/portraits/men/32.jpg" alt="User Avatar">
        </div>
        <div class="ml-3">
          <div class="text-base font-medium leading-none text-gray-800 dark:text-gray-200">John Doe</div>
          <div class="text-sm font-medium leading-none text-gray-500 dark:text-gray-400">[email protected]</div>
        </div>
        <button type="button" class="relative ml-auto flex-shrink-0 rounded-full bg-white p-1 text-gray-400 hover:text-gray-900 focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-gray-500 dark:bg-gray-800 dark:text-gray-300 dark:hover:text-white dark:focus:ring-offset-gray-700 dark:focus:ring-gray-400 transition-colors duration-200">
          <span class="absolute -inset-1.5"></span>
          <span class="sr-only">View notifications</span>
          <svg class="h-6 w-6" fill="none" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor" aria-hidden="true">
            <path stroke-linecap="round" stroke-linejoin="round" d="M14.857 17.082a23.848 23.848 0 005.454-1.31A8.967 8.967 0 0118 9.75v-.7V9A6 6 0 006 9v.75a8.967 8.967 0 01-2.312 6.022c1.733.64 3.56 1.04 5.455 1.31m5.8-3.003V12m0 8.25v-1.5m0-1.5V12m0 0a2.25 2.25 0 00-2.25 2.25V18a2.25 2.25 0 002.25 2.25h.75m0-4.5h-.75m-.75 0h-.75m-3.93-1.071c.42-.872 1.05-1.56 1.79-2.07c.74-.51 1.57-.79 2.44-.79h.75m0 0v-2.25m0 2.25h.75m0 0c.974 0 1.905-.275 2.722-.764m0 0A6.5 6.5 0 0012 2.25 6.5 6.5 0 006 8.25c0 1.62-.516 3.12-1.39 4.34m0 0L4.5 14.25m15 0a.75.75 0 00.75-.75L21 12.75l-.75-1.5a.75.75 0 00-.75-.75H3.75a.75.75 0 00-.75.75L3 12.75l.75 1.5a.75.75 0 00.75.75h15z" />
          </svg>
        </button>
      </div>
      <div class="mt-3 space-y-1 px-2">
        <a href="#" class="block rounded-md px-3 py-2 text-base font-medium text-gray-700 hover:bg-gray-100 hover:text-gray-800 dark:text-gray-300 dark:hover:bg-gray-700 dark:hover:text-white transition-colors duration-200">Your Profile</a>
        <a href="#" class="block rounded-md px-3 py-2 text-base font-medium text-gray-700 hover:bg-gray-100 hover:text-gray-800 dark:text-gray-300 dark:hover:bg-gray-700 dark:hover:text-white transition-colors duration-200">Settings</a>
        <a href="#" class="block rounded-md px-3 py-2 text-base font-medium text-gray-700 hover:bg-gray-100 hover:text-gray-800 dark:text-gray-300 dark:hover:bg-gray-700 dark:hover:text-white transition-colors duration-200">Sign out</a>
      </div>
    </div>
  </div>
</nav>