:root {
  --color-bg: #fff;
  --color-surface: #f9fafb;
  --color-text: #111827;
  --color-sub: #6b7280;
  --color-border: #e5e7eb;
  --color-primary: #2563eb;
  --color-primary-600: #1d4ed8;
  --color-danger: #ef4444;
  --color-warning: #f59e0b;
  --color-success: #10b981;
  --container: 1100px;
  --font-base: 14px;
}

* { 
  box-sizing: border-box; 
}

html, body {
  margin: 0;
  padding: 0;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, sans-serif;
}

body {
  padding: 20px;
}

h1 {
  color: var(--color-text);
  font-size: 28px;
  margin: 0 0 16px;
}

h2 {
  color: var(--color-text);
  font-size: 22px;
  margin: 0 0 12px;
}

.container {
  max-width: var(--container);
  margin: 0 auto;
}

.button, .btn {
  display: inline-block;
  padding: 10px 20px;
  background-color: var(--color-primary);
  color: white;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  font-size: 16px;
  text-decoration: none;
  text-align: center;
  transition: background-color 0.3s ease;
}

.button:hover, .btn:hover {
  background-color: var(--color-primary-600);
}

.button:disabled, .btn:disabled {
  background-color: #bdbdbd;
  color: #666666;
  cursor: not-allowed;
}

.button-secondary {
  background-color: #6b7280;
  color: white;
}

.button-secondary:hover {
  background-color: #4b5563;
}

.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 10px;
  padding: 16px;
  max-width: 680px;
  margin: 16px auto;
}

.input, input[type="text"], input[type="email"], textarea, select {
  width: 100%;
  padding: 10px;
  margin-top: 5px;
  margin-bottom: 15px;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  background: #fff;
  font-size: 16px;
  box-sizing: border-box;
}

.input:focus, input[type="text"]:focus, input[type="email"]:focus, textarea:focus, select:focus {
  outline: 2px solid var(--color-primary);
  border-color: var(--color-primary);
}

input[type="text"]::placeholder, input[type="email"]::placeholder {
  color: #ccc;
}

label {
  display: block;
  margin-top: 10px;
  font-weight: bold;
  color: var(--color-text);
}

.error {
  background-color: #fee2e2;
  border: 1px solid var(--color-danger);
  color: #7f1d1d;
  padding: 12px;
  border-radius: 8px;
  margin: 12px 0;
}

.error-message {
  color: var(--color-danger);
  font-size: 14px;
  display: none;
  margin-top: -10px;
  margin-bottom: 10px;
}

input.error, select.error {
  border-color: var(--color-danger);
  background-color: #fee2e2;
}

table {
  width: 100%;
  border-collapse: collapse;
  background: #fff;
  border: 1px solid #000;
}

th, td {
  border: 1px solid #000;
  padding: 8px;
  text-align: center;
  min-width: 60px;
}

th {
  background-color: var(--color-surface);
  font-weight: bold;
}

@media (max-width: 640px) {
  body {
    padding: 12px;
    font-size: 16px;
  }
  
  h1 {
    font-size: 24px;
  }
  
  h2 {
    font-size: 20px;
  }
  
  .button, .btn {
    padding: 14px 24px;
    font-size: 18px;
    min-height: 48px;
    width: 100%;
    text-align: center;
  }
  
  .card {
    padding: 18px;
    font-size: 16px;
  }
  
  table {
    font-size: 15px;
    table-layout: fixed;
  }
  
  table th, table td {
    min-width: 0;
    padding: 10px 4px;
  }
}