:root {
  --color-bg: #0b1221;
  --color-surface: #0f172a;
  --color-card-border: rgba(255, 255, 255, 0.08);
  --color-text: #e2e8f0;
  --color-text-secondary: #94a3b8;
  --color-primary: #0ea5e9;
  --color-secondary: #1f2937;
  --shadow-sm: 0 8px 24px rgba(0, 0, 0, 0.22);
  --shadow-md: 0 14px 40px rgba(0, 0, 0, 0.28);
  --shadow-lg: 0 24px 60px rgba(0, 0, 0, 0.35);
  --radius-sm: 8px;
  --radius-lg: 16px;
  --space-8: 8px;
  --space-12: 12px;
  --space-16: 16px;
  --space-20: 20px;
  --font-size-sm: 14px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Segoe UI", system-ui, -apple-system, sans-serif;
  color: var(--color-text);
  background: radial-gradient(110% 120% at 10% 0%, rgba(14, 165, 233, 0.18), rgba(14, 165, 233, 0)), radial-gradient(120% 140% at 90% 0%, rgba(14, 116, 144, 0.15), rgba(14, 116, 144, 0)), var(--color-bg);
  min-height: 100vh;
}

.container {
  width: min(1100px, 100%);
  margin: 0 auto;
  padding: 24px 16px;
}

h1,
h2,
h3 {
  color: var(--color-text);
}

p {
  color: var(--color-text-secondary);
}

.btn {
  cursor: pointer;
  border: 1px solid transparent;
  border-radius: 12px;
  padding: 10px 14px;
  font-weight: 600;
  color: var(--color-text);
  background: var(--color-secondary);
  transition: transform 0.12s ease, box-shadow 0.2s ease, background 0.2s ease, border-color 0.2s ease;
}

.btn:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow-sm);
}

.btn--primary {
  background: linear-gradient(135deg, #0ea5e9, #1e3a8a);
  color: #e6f6ff;
  border-color: rgba(14, 165, 233, 0.6);
  box-shadow: 0 12px 34px rgba(14, 165, 233, 0.3);
}

.btn--secondary {
  background: rgba(255, 255, 255, 0.03);
  border-color: var(--color-card-border);
}

.btn--sm {
  padding: 8px 12px;
  font-size: 14px;
}

.form-group {
  display: grid;
  gap: 8px;
}

.form-label {
  font-size: 14px;
  color: var(--color-text-secondary);
}

.form-control {
  width: 100%;
  padding: 10px 12px;
  border-radius: 12px;
  border: 1px solid var(--color-card-border);
  background: rgba(255, 255, 255, 0.03);
  color: var(--color-text);
}

.form-control:focus {
  outline: none;
  border-color: rgba(14, 165, 233, 0.6);
  box-shadow: 0 0 0 3px rgba(14, 165, 233, 0.2);
}

.form-control--inline {
  max-width: 220px;
}

.modal__close {
  background: none;
  border: none;
  color: var(--color-text);
  font-size: 24px;
  cursor: pointer;
}

.topic-card__actions {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.btn--danger {
  border-color: rgba(249, 115, 22, 0.5);
  color: #fecba1;
}

.topic-card__more {
  color: var(--color-primary);
  cursor: pointer;
}

.content-image {
  display: block;
  max-width: 100%;
  height: auto;
  margin: 12px 0;
  border-radius: 12px;
  border: 1px solid var(--color-card-border);
}

.guide-hero {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: center;
  margin-bottom: 16px;
}

.guide-actions {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.guide-content {
  background: var(--color-surface);
  border: 1px solid var(--color-card-border);
  border-radius: var(--radius-lg);
  padding: 16px;
  box-shadow: var(--shadow-sm);
  line-height: 1.7;
  word-wrap: break-word;
  overflow-wrap: break-word;
}

.guide-meta {
  display: flex;
  gap: 12px;
  color: var(--color-text-secondary);
  font-size: var(--font-size-sm);
  margin-bottom: 12px;
}

#topicEditorModal {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  justify-content: center;
  align-items: center;
  z-index: 1200;
  padding: var(--space-16);
}

#topicEditorModal .modal__content {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  max-width: 720px;
  width: 100%;
  box-shadow: var(--shadow-lg);
  overflow: hidden;
}

#topicEditorModal .modal__header,
#topicEditorModal .modal__body {
  padding: var(--space-16);
}

.modal__header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-bottom: 1px solid var(--color-card-border);
}

.modal__actions {
  display: flex;
  gap: var(--space-8);
  justify-content: flex-end;
  margin-top: var(--space-16);
}

.editor-toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
  margin: 8px 0;
}

.editor-toolbar label {
  font-size: 13px;
  color: var(--color-text-secondary);
}

.editor-preview {
  margin-top: 8px;
  padding: 12px;
  border: 1px dashed var(--color-card-border);
  border-radius: 12px;
  min-height: 80px;
  background: rgba(255, 255, 255, 0.02);
}