I don't know much CSS but want to learn slds. In trailhead, it seems to be difficullt to learn slds. Please tell me a way to learn SLDS from basics.

I am getting this as output when I am trying to run SFDX: Authorize an org in VS code.
Help me in resolving the issue.
Starting SFDX: Authorize an Org
13:02:46.506 sfdx force:auth:web:login --setalias VSCode --instanceurl https://login.salesforce.com --setdefaultusername
{ Error: spawn cmd ENOENT
    at Process.ChildProcess._handle.onexit (internal/child_process.js:240:19)
    at onErrorNT (internal/child_process.js:415:16)
    at process._tickCallback (internal/process/next_tick.js:63:19)
  errno: 'ENOENT',
  code: 'ENOENT',
  syscall: 'spawn cmd',
  path: 'cmd',
  spawnargs:
   [ '/c',
     'start',
     '""',
     '/b',
     'https://login.salesforce.com//services/oauth2/authorize?response_type=code^&client_id=PlatformCLI^&redirect_uri=http%3A%2F%2Flocalhost%3A1717%2FOauthRedirect^&state=e75f878c347c^&prompt=login^&scope=refresh_token%20api%20web^&code_challenge=vIvnJJR396aRXdnc9JSWmxIOvv08N_gsT4ryB2VOsLg' ] }
{ Error: spawn cmd ENOENT
    at Process.ChildProcess._handle.onexit (internal/child_process.js:240:19)
    at onErrorNT (internal/child_process.js:415:16)
    at process._tickCallback (internal/process/next_tick.js:63:19)
  errno: 'ENOENT',
  code: 'ENOENT',
  syscall: 'spawn cmd',
  path: 'cmd',
  spawnargs:
   [ '/c',
     'start',
     '""',
     '/b',
     'https://login.salesforce.com//services/oauth2/authorize?response_type=code^&client_id=PlatformCLI^&redirect_uri=http%3A%2F%2Flocalhost%3A1717%2FOauthRedirect^&state=e75f878c347c^&prompt=login^&scope=refresh_token%20api%20web^&code_challenge=vIvnJJR396aRXdnc9JSWmxIOvv08N_gsT4ryB2VOsLg' ] }
{ Error: spawn cmd ENOENT
    at Process.ChildProcess._handle.onexit (internal/child_process.js:240:19)
    at onErrorNT (internal/child_process.js:415:16)
    at process._tickCallback (internal/process/next_tick.js:63:19)
  errno: 'ENOENT',
  code: 'ENOENT',
  syscall: 'spawn cmd',
  path: 'cmd',
  spawnargs:
   [ '/c',
     'start',
     '""',
     '/b',
     'https://login.salesforce.com//services/oauth2/authorize?response_type=code^&client_id=PlatformCLI^&redirect_uri=http%3A%2F%2Flocalhost%3A1717%2FOauthRedirect^&state=e75f878c347c^&prompt=login^&scope=refresh_token%20api%20web^&code_challenge=vIvnJJR396aRXdnc9JSWmxIOvv08N_gsT4ryB2VOsLg' ] }
{ Error: spawn cmd ENOENT
    at Process.ChildProcess._handle.onexit (internal/child_process.js:240:19)
    at onErrorNT (internal/child_process.js:415:16)
    at process._tickCallback (internal/process/next_tick.js:63:19)
  errno: 'ENOENT',
  code: 'ENOENT',
  syscall: 'spawn cmd',
  path: 'cmd',
  spawnargs:
   [ '/c',
     'start',
     '""',
     '/b',
     'https://login.salesforce.com//services/oauth2/authorize?response_type=code^&client_id=PlatformCLI^&redirect_uri=http%3A%2F%2Flocalhost%3A1717%2FOauthRedirect^&state=e75f878c347c^&prompt=login^&scope=refresh_token%20api%20web^&code_challenge=vIvnJJR396aRXdnc9JSWmxIOvv08N_gsT4ryB2VOsLg' ] }
 

I am getting this as output when I am trying to run SFDX: Authorize an org in VS code.
Help me in resolving the issue.
Starting SFDX: Authorize an Org
13:02:46.506 sfdx force:auth:web:login --setalias VSCode --instanceurl https://login.salesforce.com --setdefaultusername
{ Error: spawn cmd ENOENT
    at Process.ChildProcess._handle.onexit (internal/child_process.js:240:19)
    at onErrorNT (internal/child_process.js:415:16)
    at process._tickCallback (internal/process/next_tick.js:63:19)
  errno: 'ENOENT',
  code: 'ENOENT',
  syscall: 'spawn cmd',
  path: 'cmd',
  spawnargs:
   [ '/c',
     'start',
     '""',
     '/b',
     'https://login.salesforce.com//services/oauth2/authorize?response_type=code^&client_id=PlatformCLI^&redirect_uri=http%3A%2F%2Flocalhost%3A1717%2FOauthRedirect^&state=e75f878c347c^&prompt=login^&scope=refresh_token%20api%20web^&code_challenge=vIvnJJR396aRXdnc9JSWmxIOvv08N_gsT4ryB2VOsLg' ] }
{ Error: spawn cmd ENOENT
    at Process.ChildProcess._handle.onexit (internal/child_process.js:240:19)
    at onErrorNT (internal/child_process.js:415:16)
    at process._tickCallback (internal/process/next_tick.js:63:19)
  errno: 'ENOENT',
  code: 'ENOENT',
  syscall: 'spawn cmd',
  path: 'cmd',
  spawnargs:
   [ '/c',
     'start',
     '""',
     '/b',
     'https://login.salesforce.com//services/oauth2/authorize?response_type=code^&client_id=PlatformCLI^&redirect_uri=http%3A%2F%2Flocalhost%3A1717%2FOauthRedirect^&state=e75f878c347c^&prompt=login^&scope=refresh_token%20api%20web^&code_challenge=vIvnJJR396aRXdnc9JSWmxIOvv08N_gsT4ryB2VOsLg' ] }
{ Error: spawn cmd ENOENT
    at Process.ChildProcess._handle.onexit (internal/child_process.js:240:19)
    at onErrorNT (internal/child_process.js:415:16)
    at process._tickCallback (internal/process/next_tick.js:63:19)
  errno: 'ENOENT',
  code: 'ENOENT',
  syscall: 'spawn cmd',
  path: 'cmd',
  spawnargs:
   [ '/c',
     'start',
     '""',
     '/b',
     'https://login.salesforce.com//services/oauth2/authorize?response_type=code^&client_id=PlatformCLI^&redirect_uri=http%3A%2F%2Flocalhost%3A1717%2FOauthRedirect^&state=e75f878c347c^&prompt=login^&scope=refresh_token%20api%20web^&code_challenge=vIvnJJR396aRXdnc9JSWmxIOvv08N_gsT4ryB2VOsLg' ] }
{ Error: spawn cmd ENOENT
    at Process.ChildProcess._handle.onexit (internal/child_process.js:240:19)
    at onErrorNT (internal/child_process.js:415:16)
    at process._tickCallback (internal/process/next_tick.js:63:19)
  errno: 'ENOENT',
  code: 'ENOENT',
  syscall: 'spawn cmd',
  path: 'cmd',
  spawnargs:
   [ '/c',
     'start',
     '""',
     '/b',
     'https://login.salesforce.com//services/oauth2/authorize?response_type=code^&client_id=PlatformCLI^&redirect_uri=http%3A%2F%2Flocalhost%3A1717%2FOauthRedirect^&state=e75f878c347c^&prompt=login^&scope=refresh_token%20api%20web^&code_challenge=vIvnJJR396aRXdnc9JSWmxIOvv08N_gsT4ryB2VOsLg' ] }