:root {
  color-scheme: light;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: #f3f5f9;
  color: #111827;
  --surface: #ffffff;
  --surface-muted: #f8fafc;
  --border: #e5e7eb;
  --text: #111827;
  --text-muted: #6b7280;
  --nav: #111827;
  --nav-text: #f8fafc;
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --danger: #dc2626;
  --shadow: 0 18px 50px rgba(15, 23, 42, 0.08);
}
* {
  box-sizing: border-box;
}
body {
  margin: 0;
  min-height: 100vh;
  background: linear-gradient(180deg, #f8fafc 0%, #eef2ff 100%);
  color: var(--text);
}
img {
  max-width: 100%;
  display: block;
}
a {
  color: var(--primary);
}
a:hover {
  text-decoration: underline;
}
header {
  background: var(--nav);
  color: var(--nav-text);
  padding: 18px 24px;
}
header .container {
  max-width: 1120px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}
.logo {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  font-size: 1.05rem;
  font-weight: 700;
}
.logo img {
  width: 34px;
  height: 34px;
}
nav {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}
nav a {
  color: var(--nav-text);
  font-weight: 600;
  opacity: 0.88;
}
nav a:hover {
  opacity: 1;
}
.container-main {
  max-width: 1120px;
  margin: 0 auto;
  padding: 28px 24px 44px;
}
.page-hero {
  text-align: center;
  padding: 48px 0 42px;
}
.page-hero .logo-large {
  width: 180px;
  margin: 0 auto 28px;
}
.page-hero h1 {
  margin: 0 auto 0.75rem;
  font-size: clamp(2.75rem, 4vw, 4.25rem);
  line-height: 1.02;
}
.page-hero h2 {
  margin: 0 auto;
  max-width: 760px;
  font-size: 1.15rem;
  font-weight: 500;
  color: var(--text-muted);
  line-height: 1.8;
}
.feature-grid {
  display: grid;
  gap: 20px;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  margin-top: 34px;
}
.feature-card {
  background: var(--surface);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  border-radius: 18px;
  padding: 26px;
}
.feature-card h3 {
  margin: 0 0 12px;
  font-size: 1.05rem;
}
.feature-card p {
  margin: 0;
  color: var(--text-muted);
  line-height: 1.75;
}
.footer {
  padding: 24px 0;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.95rem;
}
.login-grid {
  display: grid;
  gap: 24px;
  grid-template-columns: repeat(auto-fit, minmax(320px, 560px));
  justify-content: center;
  padding: 48px 0;
}
.login-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 20px;
  box-shadow: var(--shadow);
  padding: 32px;
}
.login-card h1,
.login-card h2 {
  margin: 0 0 14px;
}
.login-card h1 {
  font-size: 1.55rem;
}
.login-card h2 {
  font-size: 1.2rem;
}
.login-card p {
  margin: 0 0 24px;
  color: var(--text-muted);
  line-height: 1.7;
}
.help-card {
  display: grid;
  gap: 18px;
}
.help-card a {
  display: block;
  color: var(--primary);
}
.field-group {
  display: grid;
  gap: 10px;
  margin-bottom: 18px;
}
label {
  color: var(--text);
  font-weight: 600;
}
input[type="text"],
input[type="password"] {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 14px 16px;
  font-size: 1rem;
  background: var(--surface-muted);
  color: var(--text);
}
input[type="text"]:focus,
input[type="password"]:focus {
  border-color: var(--primary);
  outline: none;
}
.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 13px 18px;
  border-radius: 14px;
  font-weight: 700;
  cursor: pointer;
  border: none;
}
.button.primary {
  background: var(--primary);
  color: #ffffff;
}
.button.primary:hover {
  background: var(--primary-dark);
}
.button.secondary {
  background: var(--surface-muted);
  color: var(--text);
  border: 1px solid var(--border);
}
.button.secondary:hover {
  background: #eef2ff;
}
.checkbox-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 22px;
}
.checkbox-label {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--text-muted);
  font-size: 0.95rem;
}
input[type="checkbox"] {
  width: 16px;
  height: 16px;
  accent-color: var(--primary);
}
.alert {
  display: none;
  padding: 14px 16px;
  border-radius: 14px;
  background: #fef2f2;
  border: 1px solid #fecaca;
  color: #991b1b;
  margin-bottom: 18px;
}
@media (max-width: 820px) {
  nav {
    justify-content: center;
  }
  .page-hero {
    padding: 32px 0 26px;
  }
  .feature-grid,
  .login-grid {
    grid-template-columns: 1fr;
  }
}