:root {
  --bg: #f4f6f8;
  --surface: #ffffff;
  --surface-2: #f8fafc;
  --text: #102033;
  --muted: #586274;
  --border: #d9e0e8;
  --primary: #1362d6;
  --primary-hover: #0f52b2;
  --success: #1f7a4f;
  --warn: #9a5a13;
  --danger: #b3261e;
  --shadow: 0 12px 30px rgba(11, 24, 40, 0.08);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Manrope", "Segoe UI", sans-serif;
  color: var(--text);
  background: linear-gradient(145deg, #edf2f6, #f8fbfd);
}

.app-shell {
  max-width: 1100px;
  margin: 0 auto;
  padding: 24px;
  display: grid;
  gap: 16px;
  grid-template-columns: repeat(12, 1fr);
}

.panel {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  box-shadow: var(--shadow);
  padding: 20px;
}

.control-panel {
  grid-column: span 4;
}

.practice-panel {
  grid-column: span 8;
}

.metrics-panel {
  grid-column: span 12;
}

h1,
h2 {
  margin: 0;
}

.subtitle {
  margin: 8px 0 18px;
  color: var(--muted);
}

.mode-group {
  display: flex;
  gap: 10px;
  margin-bottom: 16px;
}

.mode-btn,
.primary-btn,
.secondary-btn {
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 10px 14px;
  font: inherit;
  font-weight: 600;
  cursor: pointer;
  transition: transform 140ms ease, background-color 140ms ease, border-color 140ms ease;
}

.mode-btn {
  background: var(--surface-2);
  color: var(--text);
}

.mode-btn.is-active {
  border-color: var(--primary);
  color: var(--primary);
  background: #ecf3ff;
}

.mode-btn:hover,
.primary-btn:hover,
.secondary-btn:hover {
  transform: translateY(-1px);
}

.primary-btn {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}

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

.secondary-btn {
  background: var(--surface-2);
}

.session-actions {
  display: flex;
  gap: 10px;
  margin-bottom: 12px;
}

.tips {
  color: var(--muted);
  background: var(--surface-2);
  border-radius: 10px;
  padding: 12px;
  min-height: 48px;
}

.target-text {
  margin-top: 10px;
  padding: 14px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--surface-2);
  font-family: "JetBrains Mono", monospace;
  line-height: 1.7;
  min-height: 110px;
}

.char-correct {
  color: var(--success);
}

.char-wrong {
  color: var(--danger);
  text-decoration: underline;
}

.char-current {
  background: #dfeaff;
}

.input-label {
  display: block;
  margin: 14px 0 8px;
  font-weight: 600;
}

.typing-input {
  width: 100%;
  resize: vertical;
  border-radius: 10px;
  border: 1px solid var(--border);
  padding: 12px;
  font: 400 1rem/1.5 "JetBrains Mono", monospace;
}

.typing-input:focus {
  outline: 2px solid #7faef6;
  border-color: var(--primary);
}

.status {
  color: var(--muted);
  margin: 10px 0 0;
}

.metrics-list {
  list-style: none;
  margin: 12px 0 16px;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(4, minmax(120px, 1fr));
  gap: 10px;
}

.metrics-list li {
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px;
  background: var(--surface-2);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.metrics-list span {
  color: var(--muted);
  font-size: 0.95rem;
}

.metrics-list strong {
  font-size: 1.15rem;
}

.feedback-box {
  border: 1px dashed var(--border);
  border-radius: 10px;
  padding: 12px;
  background: #fcfdfe;
}

@media (max-width: 900px) {
  .control-panel,
  .practice-panel,
  .metrics-panel {
    grid-column: span 12;
  }

  .metrics-list {
    grid-template-columns: repeat(2, minmax(120px, 1fr));
  }
}

@media (max-width: 540px) {
  .app-shell {
    padding: 14px;
  }

  .panel {
    padding: 16px;
  }

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