html {
  box-sizing: border-box;
  font-size: 17px;
  background: #fafbfc;
}
*,*:before,*:after { box-sizing: inherit; }
body {
  margin: 0; padding: 0;
  font-family: -apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,'Helvetica Neue',Arial,sans-serif;
  background: #fafbfc;
  color: #212529;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}
.main-header {
  background: #2166e3;
  box-shadow: 0 1px 2px rgba(0,0,0,0.02);
}
.main-nav {
  max-width: 940px;
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 22px;
  padding: 0.5em 1em;
}
.main-nav a {
  color: #fff;
  text-decoration: none;
  font-weight: 500;
  padding: 7px 12px;
  border-radius: 4px;
  transition: background 0.15s;
}
.main-nav a.active,
.main-nav a:hover {
  background: #154ca7;
}
.main-nav form {
  display: inline;
}
.logout {
  color: #fff;
  background: #e34f4f;
  border: none;
  border-radius: 4px;
  padding: 7px 16px;
  font-size: 1em;
  cursor: pointer;
  transition: background 0.14s;
}
.logout:hover {
  background: #a22b2b;
}
.main-content {
  flex: 1 1 auto;
  max-width: 940px;
  margin: 32px auto 24px auto;
  background: #fff;
  border-radius: 10px;
  box-shadow: 0 2px 10px rgba(33,102,227,0.06),0 1.5px 6px rgba(60,68,88,0.04);
  padding: 1.7em 1.5em 1.7em 1.5em;
}
h1, h2, h3 {
  color: #192037;
  margin-top: 0;
  font-weight: 600;
}
footer.footer {
  background: #eaf1fb;
  color: #777;
  padding: 16px 0;
  text-align: center;
  font-size: .93em;
  border-top: 1px solid #e7e7e7;
  margin-top: auto;
}
/* Form styles */
form {
  max-width: 360px;
  margin: 26px auto 0 auto;
  display: flex;
  flex-direction: column;
  gap: 14px;
}
label {
  font-size: 1.05em;
  font-weight: 500;
  margin-bottom: 6px;
  color: #333;
}
input[type="text"],
input[type="password"],
input[type="email"] {
  border: 1px solid #c6defb;
  border-radius: 5px;
  padding: 10px;
  font-size: 1em;
  transition: border 0.13s;
  background: #f5f7fa;
}
input[type="text"]:focus,
input[type="password"]:focus,
input[type="email"]:focus {
  outline: none;
  border-color: #2166e3;
}
button, input[type="submit"] {
  background: #2166e3;
  color: #fff;
  font-weight: 600;
  border: none;
  border-radius: 5px;
  padding: 10px 0;
  font-size: 1em;
  cursor: pointer;
  margin-top: 7px;
  transition: background 0.15s;
}
button:hover, input[type="submit"]:hover {
  background: #154ca7;
}
.alert-success, .alert-danger, .alert-info {
  padding: 13px 20px;
  margin-bottom: 14px;
  border-radius: 5px;
  font-size: 1.08em;
}
.alert-success { background: #e8f5e9; color: #245330; border-left: 5px solid #50a060; }
.alert-danger { background: #ffeded; color: #a22b2b; border-left: 5px solid #e34f4f; }
.alert-info { background: #e7f2fd; color: #1a4869; border-left: 5px solid #2166e3; }
/* Mobile: make everything readable */
@media (max-width: 600px) {
  .main-nav {
    flex-direction: column;
    gap: 8px;
    padding: 0.85em 0.45em;
  }
  .main-content {
    margin: 20px 6px;
    padding: 0.9em 0.4em 1.1em 0.4em;
  }
  form {
    max-width: 98%;
    margin-left: auto;
    margin-right: auto;
  }
  footer.footer {
    font-size: 0.98em;
  }
}