:root {
  --bg: #f4f7fb;
  --card: #ffffff;
  --text: #111827;
  --muted: #6b7280;
  --border: #dbe2ea;
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --secondary: #eef2f7;
  --shadow: 0 14px 40px rgba(0, 0, 0, 0.08);
}

body.dark {
  --bg: #0f172a;
  --card: #111827;
  --text: #f9fafb;
  --muted: #9ca3af;
  --border: #374151;
  --primary: #3b82f6;
  --primary-hover: #60a5fa;
  --secondary: #1f2937;
  --shadow: 0 14px 40px rgba(0, 0, 0, 0.35);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  padding: 40px 20px;
  font-family: Arial, Helvetica, sans-serif;
  background: var(--bg);
  color: var(--text);
  transition: 0.25s ease;
}

.container {
  max-width: 900px;
  margin: auto;
  background: var(--card);
  padding: 32px;
  border-radius: 20px;
  box-shadow: var(--shadow);
}

.top-bar {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 20px;
  margin-bottom: 28px;
}

h1 {
  margin: 0 0 10px;
  font-size: 36px;
}

.subtitle {
  margin: 0;
  color: var(--muted);
  line-height: 1.6;
}

.grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 18px;
}

.field {
  margin-bottom: 18px;
}

label {
  display: block;
  margin-bottom: 8px;
  font-weight: 700;
}

select,
input,
textarea {
  width: 100%;
  border: 1px solid var(--border);
  background: var(--card);
  color: var(--text);
  padding: 13px 14px;
  border-radius: 10px;
  font-size: 15px;
  outline: none;
}

select:focus,
input:focus,
textarea:focus {
  border-color: var(--primary);
}

textarea {
  resize: vertical;
  line-height: 1.6;
  min-height: 260px;
}

.topic-row {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 10px;
}

button {
  border: none;
  border-radius: 10px;
  padding: 13px 18px;
  cursor: pointer;
  font-weight: 700;
  font-size: 14px;
  transition: 0.2s ease;
}

.primary-button {
  width: 100%;
  background: var(--primary);
  color: white;
  margin-bottom: 24px;
}

.primary-button:hover {
  background: var(--primary-hover);
}

.secondary-button,
.theme-button {
  background: var(--secondary);
  color: var(--text);
}

.secondary-button:hover,
.theme-button:hover {
  transform: translateY(-1px);
}

.output-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

#status {
  color: var(--muted);
  font-size: 13px;
}

.action-row {
  display: flex;
  gap: 10px;
  margin-top: 12px;
}

.action-row button {
  flex: 1;
}

footer {
  margin-top: 30px;
  padding-top: 18px;
  border-top: 1px solid var(--border);
  text-align: center;
  color: var(--muted);
  font-size: 13px;
}

@media (max-width: 700px) {
  body {
    padding: 16px;
  }

  .container {
    padding: 22px;
  }

  .top-bar {
    flex-direction: column;
  }

  h1 {
    font-size: 28px;
  }

  .grid {
    grid-template-columns: 1fr;
  }

  .topic-row {
    grid-template-columns: 1fr;
  }

  .action-row {
    flex-direction: column;
  }

  .theme-button {
    width: 100%;
  }
}