/* style.css – Dark theme với bố cục 2 cột cho chọn quốc gia / thành phố */
:root {
  --bg-body: #0d1117;
  --bg-card: #161b22;
  --bg-input: #0d1117;
  --border-color: #30363d;
  --text-primary: #f0f6fc;
  --text-secondary: #8b949e;
  --accent-blue: #58a6ff;
  --accent-green: #3fb950;
  --accent-orange: #d29922;
  --accent-red: #f85149;
  --shadow: 0 8px 24px rgba(0, 0, 0, 0.5);
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Segoe UI', 'Roboto', system-ui, sans-serif;
}

body {
  background-color: var(--bg-body);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 1.5rem;
}

.container {
  background-color: var(--bg-card);
  border-radius: 24px;
  padding: 2rem 2rem 1.5rem;
  max-width: 820px;
  width: 100%;
  box-shadow: var(--shadow);
  border: 1px solid var(--border-color);
}

header {
  text-align: center;
  margin-bottom: 1.8rem;
}

header h1 {
  font-size: 2rem;
  font-weight: 600;
  color: var(--text-primary);
  letter-spacing: -0.5px;
}

header .subtitle {
  color: var(--text-secondary);
  font-size: 0.95rem;
  margin-top: 0.2rem;
}

label {
  display: block;
  font-weight: 500;
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-bottom: 0.4rem;
  letter-spacing: 0.3px;
}

textarea {
  width: 100%;
  background-color: var(--bg-input);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 0.9rem 1rem;
  font-size: 0.95rem;
  line-height: 1.6;
  resize: vertical;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
  outline: none;
}

textarea:focus {
  border-color: var(--accent-blue);
  box-shadow: 0 0 0 3px rgba(88, 166, 255, 0.2);
}

textarea[readonly] {
  cursor: default;
  background-color: #0d1117;
}

.input-section,
.timezone-section,
.output-section {
  margin-bottom: 1.2rem;
}

/* Timezone row: 2 cột */
.timezone-row {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

.timezone-group {
  flex: 1 1 200px;
  min-width: 150px;
}

.timezone-section select {
  width: 100%;
  padding: 0.7rem 1rem;
  background-color: var(--bg-input);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  font-size: 0.95rem;
  outline: none;
  cursor: pointer;
  transition: border-color 0.2s;
}

.timezone-section select:focus {
  border-color: var(--accent-blue);
}

.timezone-section select option {
  background-color: var(--bg-card);
  color: var(--text-primary);
}

.timezone-info {
  margin-top: 0.5rem;
  font-size: 0.9rem;
  color: var(--text-secondary);
  padding: 0.3rem 0.5rem;
  border-left: 3px solid var(--accent-blue);
  background: rgba(88, 166, 255, 0.05);
  border-radius: 6px;
}

/* Format Selector */
.format-select-section {
  margin-bottom: 1rem;
}

.format-select-section select {
  width: 100%;
  padding: 0.6rem 1rem;
  background-color: var(--bg-input);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  font-size: 0.95rem;
  outline: none;
  cursor: pointer;
}

.format-select-section select:focus {
  border-color: var(--accent-blue);
}

.format-select-section select option {
  background-color: var(--bg-card);
  color: var(--text-primary);
}

.button-group {
  display: flex;
  flex-wrap: wrap;
  gap: 0.8rem;
  margin-bottom: 1.5rem;
  justify-content: center;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  padding: 0.65rem 1.4rem;
  border: none;
  border-radius: 40px;
  font-weight: 600;
  font-size: 0.9rem;
  background-color: var(--border-color);
  color: var(--text-primary);
  cursor: pointer;
  transition: background-color 0.2s, transform 0.1s, box-shadow 0.2s;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.3);
  flex: 0 1 auto;
}

.btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 14px rgba(0, 0, 0, 0.4);
}

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

.btn-primary {
  background-color: var(--accent-blue);
  color: #0d1117;
}
.btn-primary:hover {
  background-color: #79c0ff;
}

.btn-secondary {
  background-color: var(--accent-green);
  color: #0d1117;
}
.btn-secondary:hover {
  background-color: #56d36e;
}

.btn-copy {
  background-color: var(--accent-orange);
  color: #0d1117;
}
.btn-copy:hover {
  background-color: #e3b341;
}

.btn-reset {
  background-color: var(--accent-red);
  color: #ffffff;
}
.btn-reset:hover {
  background-color: #ff7b72;
}

footer {
  margin-top: 1.8rem;
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.85rem;
  border-top: 1px solid var(--border-color);
  padding-top: 1.2rem;
}

footer a {
  color: var(--accent-blue);
  text-decoration: none;
}
footer a:hover {
  text-decoration: underline;
}

/* Responsive */
@media (max-width: 600px) {
  .container {
    padding: 1.2rem;
  }
  header h1 {
    font-size: 1.6rem;
  }
  .button-group {
    flex-direction: column;
    align-items: stretch;
  }
  .btn {
    justify-content: center;
    padding: 0.7rem;
  }
  .timezone-row {
    flex-direction: column;
    gap: 0.5rem;
  }
}