:root {
  --bg-gradient-start: #ffffff;
  --bg-gradient-end: #f5f5f5;
  --card-bg: rgba(255, 255, 255, 0.6);
  --card-border: rgba(0, 0, 0, 0.05);
  --text-primary: #0a0a0a;
  --text-secondary: #737373;
  --link-bg: rgba(255, 255, 255, 0.8);
  --link-bg-hover: #ffffff;
  --link-border: rgba(0, 0, 0, 0.06);
  --link-border-hover: rgba(0, 0, 0, 0.1);
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 20px 40px rgba(0, 0, 0, 0.02);
  --shadow-hover: 0 4px 12px rgba(0, 0, 0, 0.08);
}

:root[data-theme="dark"] {
  --bg-gradient-start: #0a0a0a;
  --bg-gradient-end: #171717;
  --card-bg: rgba(23, 23, 23, 0.6);
  --card-border: rgba(255, 255, 255, 0.1);
  --text-primary: #fafafa;
  --text-secondary: #a3a3a3;
  --link-bg: rgba(38, 38, 38, 0.8);
  --link-bg-hover: rgba(50, 50, 50, 1);
  --link-border: rgba(255, 255, 255, 0.08);
  --link-border-hover: rgba(255, 255, 255, 0.15);
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 20px 40px rgba(0, 0, 0, 0.5);
  --shadow-hover: 0 4px 12px rgba(0, 0, 0, 0.4);
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: "DM Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    sans-serif;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  background: linear-gradient(
    to bottom,
    var(--bg-gradient-start) 0%,
    var(--bg-gradient-end) 100%
  );
  padding: 40px 20px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background 0.3s ease;
  position: relative;
}

.theme-toggle {
  position: absolute;
  top: 20px;
  right: 20px;
  background: var(--link-bg);
  border: 1px solid var(--link-border);
  border-radius: 50px;
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: none;
  z-index: 10;
}

.theme-toggle:hover {
  background: var(--link-bg-hover);
  border-color: var(--link-border-hover);
  transform: scale(1.05);
}

.theme-toggle svg {
  width: 18px;
  height: 18px;
  stroke: var(--text-primary);
  transition: all 0.3s ease;
}

.theme-toggle .sun-icon {
  display: none;
}

.theme-toggle .moon-icon {
  display: block;
}

:root[data-theme="dark"] .theme-toggle .sun-icon {
  display: block;
}

:root[data-theme="dark"] .theme-toggle .moon-icon {
  display: none;
}

.card {
  position: relative;
  text-align: center;
  max-width: 440px;
  width: 100%;
  background: var(--card-bg);
  backdrop-filter: blur(20px);
  border-radius: 24px;
  padding: 56px 48px;
  box-shadow: var(--shadow-sm), var(--shadow-md);
  border: 1px solid var(--card-border);
  transition: all 0.3s ease;
}

.logo {
  width: 88px;
  height: 88px;
  margin: 0 auto 36px;
  opacity: 0.95;
  transition: transform 0.3s ease, opacity 0.3s ease;
}

.logo:hover {
  transform: scale(1.05);
  opacity: 1;
}

h1 {
  font-size: 2.25rem;
  color: var(--text-primary);
  margin-bottom: 12px;
  font-weight: 600;
  letter-spacing: -0.03em;
  line-height: 1.2;
  transition: color 0.3s ease;
}

.subtitle {
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin-bottom: 56px;
  font-weight: 400;
  letter-spacing: -0.01em;
  transition: color 0.3s ease;
}

.links {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

a {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 18px 24px;
  background: var(--link-bg);
  color: var(--text-primary);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 500;
  transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  border-radius: 12px;
  border: 1px solid var(--link-border);
  box-shadow: var(--shadow-sm);
  letter-spacing: -0.01em;
}

a:hover {
  background: var(--link-bg-hover);
  border-color: var(--link-border-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-hover);
}

a:active {
  transform: translateY(0);
}

.icon {
  margin-right: 12px;
  width: 20px;
  height: 20px;
  opacity: 0.7;
  stroke-width: 2;
  transition: opacity 0.2s ease;
}

a:hover .icon {
  opacity: 0.9;
}

@media (max-width: 600px) {
  body {
    padding: 20px;
  }

  .theme-toggle {
    top: 16px;
    right: 16px;
    width: 32px;
    height: 32px;
  }

  .theme-toggle svg {
    width: 16px;
    height: 16px;
  }

  .card {
    padding: 44px 32px;
  }

  .logo {
    width: 72px;
    height: 72px;
    margin-bottom: 30px;
  }

  h1 {
    font-size: 1.85rem;
    margin-bottom: 10px;
  }

  .subtitle {
    font-size: 0.875rem;
    margin-bottom: 44px;
  }

  a {
    font-size: 0.9rem;
    padding: 16px 20px;
  }
}