:root {
  --bg-page: #f5f7fa;
  --bg-card: #ffffff;
  --bg-subtle: #f9fafb;
  --text-main: #1f2937;
  --text-heading: #374151;
  --text-muted: #6b7280;
  --text-light: #9ca3af;
  --border-color: #e5e7eb;
  --border-input: #d1d5db;
  --card-shadow: 0 8px 30px rgba(0, 0, 0, 0.08);
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --danger: #dc2626;
  --font-family: Arial, Helvetica, sans-serif;
  --radius-lg: 12px;
  --radius-md: 8px;
}

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

body {
  margin: 0;
  min-height: 100vh;
  background-color: var(--bg-page);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-family);
  color: var(--text-main);
  line-height: 1.6;
}

/* ----------------------------------------------------
   Center Card Layout
   ---------------------------------------------------- */
.error-container {
  width: 100%;
  max-width: 600px;
  padding: 20px;
}

.error-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  box-shadow: var(--card-shadow);
  overflow: hidden;
}

.error-content {
  min-height: 360px;
  padding: 45px 40px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
}

.error-logo {
  max-width: 180px;
  height: auto;
  margin-bottom: 35px;
}

.error-code {
  margin: 0 0 8px;
  font-size: 56px;
  line-height: 1;
  font-weight: 700;
  color: var(--text-main);
}

.error-title {
  margin: 0 0 16px;
  font-size: 24px;
  font-weight: 600;
  color: var(--text-heading);
}

.error-message {
  max-width: 460px;
  margin: 0;
  font-size: 15px;
  line-height: 1.7;
  color: var(--text-muted);
}

.error-footer {
  padding: 16px 25px;
  background: var(--bg-subtle);
  border-top: 1px solid var(--border-color);
  text-align: center;
  font-size: 12px;
  color: var(--text-light);
}

/* ----------------------------------------------------
   Button Styles
   ---------------------------------------------------- */
.image-button {
  max-width: 240px;
  width: 100%;
  height: auto;
  cursor: pointer;
  display: block;
  margin: 0 auto;
  border-radius: var(--radius-md);
  transition: transform 0.15s ease, opacity 0.15s ease;
}

.image-button:hover {
  transform: scale(1.02);
  opacity: 0.95;
}

.image-button:active {
  transform: scale(0.99);
}

#btn_signwith {
  cursor: pointer;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-weight: 500;
  padding: 9px 20px;
  font-size: 14px;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  cursor: pointer;
  text-decoration: none;
  transition: all 0.15s ease-in-out;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.05);
}

.btn-secondary {
  color: var(--text-heading);
  background-color: #ffffff;
  border-color: var(--border-input);
}

.btn-secondary:hover {
  background-color: var(--bg-subtle);
  border-color: var(--text-light);
  color: var(--text-main);
  transform: translateY(-1px);
}

.btn-secondary:active {
  transform: translateY(0);
}

/* ----------------------------------------------------
   Helper Elements
   ---------------------------------------------------- */
.user-badge-pill {
  display: inline-flex;
  align-items: center;
  padding: 6px 14px;
  background: var(--bg-subtle);
  border: 1px solid var(--border-color);
  border-radius: 20px;
  font-weight: 600;
  color: var(--text-heading);
  font-size: 14px;
  margin-bottom: 20px;
}

.instruction-box {
  background: var(--bg-subtle);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 12px 18px;
  font-size: 14px;
  color: var(--text-heading);
  margin-bottom: 10px;
}

/* ----------------------------------------------------
   Mobile Responsiveness
   ---------------------------------------------------- */
@media (max-width: 576px) {
  .error-container {
    padding: 15px;
  }
  .error-content {
    min-height: 320px;
    padding: 35px 25px;
  }
  .error-code {
    font-size: 46px;
  }
  .error-title {
    font-size: 21px;
  }
  .error-logo {
    max-width: 150px;
    margin-bottom: 28px;
  }
  .image-button {
    max-width: 200px;
  }
}