:root {
  --bg: #f4f6fb;
  --card: #ffffff;
  --text: #172033;
  --muted: #637089;
  --primary: #375dfb;
  --primary-soft: #e9eeff;
  --success: #138a42;
  --danger: #c92a2a;
  --border: #dce3f1;
  --radius: 14px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Noto Sans KR", sans-serif;
  background: linear-gradient(180deg, #eef2ff, var(--bg));
  color: var(--text);
}

.app {
  max-width: 760px;
  margin: 0 auto;
  padding: 20px 14px 32px;
}

.app__header {
  margin-bottom: 14px;
}

h1, h2, h3, p { margin: 0; }
.subtitle { color: var(--muted); margin-top: 6px; }

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  margin: 12px 0;
  box-shadow: 0 8px 20px rgba(31, 50, 90, 0.06);
}

label { display: block; font-weight: 600; margin-bottom: 8px; }
input[type="url"],
input[type="password"],
input[type="text"] {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 10px 12px;
  font-size: 15px;
  margin-bottom: 10px;
}

button {
  border: none;
  border-radius: 10px;
  padding: 10px 14px;
  background: var(--primary);
  color: #fff;
  font-weight: 600;
  cursor: pointer;
}

button:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.btn-ghost {
  background: transparent;
  color: var(--muted);
  border: 1px solid var(--border);
}

.status { margin-top: 8px; color: var(--muted); min-height: 18px; }

.controls h2 { margin-bottom: 8px; }
.top-actions { margin: 12px 0 14px; }

.progress-wrap { margin-bottom: 16px; }
.progress-meta {
  display: flex;
  justify-content: space-between;
  color: var(--muted);
  margin-bottom: 8px;
  font-size: 14px;
}
.progress-bar {
  width: 100%;
  height: 10px;
  background: #edf1f8;
  border-radius: 999px;
  overflow: hidden;
}
.progress-fill {
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, #4f77ff, #2b59ff);
  transition: width 0.25s ease;
}

.question-image {
  width: 100%;
  border-radius: 10px;
  margin: 10px 0;
}

.question-title { font-size: 1.08rem; font-weight: 700; margin-bottom: 10px; }
.choices { display: grid; gap: 8px; margin-bottom: 12px; }
.choice {
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 10px;
  display: flex;
  align-items: center;
  gap: 8px;
}

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

.feedback { margin-top: 10px; min-height: 20px; font-weight: 600; }
.feedback.success { color: var(--success); }
.feedback.fail { color: var(--danger); }

.explanations { margin-top: 12px; display: grid; gap: 10px; }
.explanation-item { border-top: 1px dashed var(--border); padding-top: 10px; }

.section-title-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 10px;
}

#wrongList {
  margin: 0;
  padding-left: 18px;
  display: grid;
  gap: 8px;
  color: var(--muted);
}

.modal {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.42);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 14px;
}
.modal-content {
  background: #fff;
  width: min(420px, 100%);
  border-radius: 12px;
  padding: 16px;
}
.modal-actions { margin-top: 8px; }
.error { color: var(--danger); min-height: 18px; }

.hidden { display: none !important; }

@media (max-width: 480px) {
  .app { padding: 14px 10px 24px; }
  .card { padding: 14px; }
  button { width: 100%; }
  .actions button { flex: 1 1 100%; }
}