/* =========================================================
   Easy Logic — DSE Argumentative Writing
   Clean, mobile-friendly, white + navy accents.
   ========================================================= */

:root {
  --navy: #0b2545;
  --navy-700: #13315c;
  --navy-500: #1e4b8f;
  --accent: #ffd166;     /* soft yellow for hints */
  --accent-bg: #fff8dc;
  --good: #2a9d8f;
  --bad: #e63946;
  --text: #1a1a1a;
  --muted: #6c757d;
  --line: #e5e7eb;
  --bg: #ffffff;
  --bg-soft: #f7f8fa;
  --radius: 10px;
  --shadow: 0 2px 12px rgba(11, 37, 69, 0.08);
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang TC",
          "Microsoft JhengHei", "Helvetica Neue", Arial, sans-serif;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  font-family: var(--font);
  color: var(--text);
  background: var(--bg-soft);
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: 880px;
  margin: 0 auto;
  padding: 0 20px;
}

/* ---------- Header ---------- */
.site-header {
  background: linear-gradient(135deg, var(--navy) 0%, var(--navy-500) 100%);
  color: #fff;
  padding: 32px 0 28px;
}
.site-title {
  margin: 0;
  font-size: 28px;
  letter-spacing: 0.5px;
}
.site-title .subtitle {
  font-size: 18px;
  font-weight: 400;
  opacity: 0.85;
  margin-left: 8px;
}
.tagline {
  margin: 6px 0 0;
  opacity: 0.9;
  font-size: 14px;
}

/* ---------- Steps Navigation ---------- */
.steps-nav {
  margin-top: -18px;
  margin-bottom: 24px;
}
.steps {
  list-style: none;
  display: flex;
  gap: 8px;
  padding: 12px;
  margin: 0;
  background: #fff;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow-x: auto;
}
.step {
  flex: 1;
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  border-radius: 8px;
  font-size: 14px;
  color: var(--muted);
  background: var(--bg-soft);
  min-width: 140px;
}
.step .num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 26px; height: 26px;
  border-radius: 50%;
  background: #d8dee9;
  color: #fff;
  font-weight: 700;
  font-size: 13px;
}
.step.active {
  background: var(--navy);
  color: #fff;
}
.step.active .num { background: var(--accent); color: var(--navy); }
.step.done { background: #e6f4ea; color: var(--good); }
.step.done .num { background: var(--good); }

/* ---------- Step Panels ---------- */
.step-panel {
  display: none;
  background: #fff;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 24px;
  margin-bottom: 24px;
}
.step-panel.active { display: block; }

.step-panel h2 {
  margin: 0 0 6px;
  color: var(--navy);
  font-size: 20px;
}
.muted { color: var(--muted); font-size: 14px; margin: 0 0 18px; }

/* ---------- Form / Chips ---------- */
.form-row { margin-bottom: 18px; }
.form-label {
  display: block;
  margin-bottom: 8px;
  font-weight: 600;
  font-size: 14px;
  color: var(--navy-700);
}
.chip-group {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.chip {
  border: 1.5px solid var(--line);
  background: #fff;
  color: var(--text);
  padding: 8px 14px;
  border-radius: 20px;
  cursor: pointer;
  font-size: 14px;
  transition: all 0.15s ease;
  font-family: inherit;
}
.chip:hover { border-color: var(--navy-500); }
.chip.selected {
  background: var(--navy);
  color: #fff;
  border-color: var(--navy);
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-block;
  padding: 11px 22px;
  border-radius: 8px;
  border: none;
  font-weight: 600;
  font-size: 15px;
  cursor: pointer;
  font-family: inherit;
  transition: opacity 0.15s, transform 0.05s;
}
.btn:active { transform: translateY(1px); }
.btn:disabled { opacity: 0.45; cursor: not-allowed; }
.btn.primary {
  background: var(--navy);
  color: #fff;
}
.btn.primary:hover:not(:disabled) { background: var(--navy-500); }
.btn.secondary {
  background: #fff;
  color: var(--navy);
  border: 1.5px solid var(--navy);
}
.btn.ghost {
  background: transparent;
  color: var(--navy);
  border: 1px solid var(--line);
  font-size: 13px;
  padding: 6px 12px;
}
.btn.ghost:hover { background: var(--bg-soft); }

/* ---------- Cards ---------- */
.card {
  background: var(--bg-soft);
  border-left: 4px solid var(--navy);
  border-radius: var(--radius);
  padding: 18px 20px;
  margin-top: 20px;
}
.card-label {
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--navy-500);
  font-weight: 700;
  margin-bottom: 10px;
}
.card h3 {
  margin: 14px 0 4px;
  font-size: 15px;
  color: var(--navy-700);
}
.card h3:first-of-type { margin-top: 4px; }
.card p { margin: 0 0 8px; }

/* ---------- Chain (Step 2) ---------- */
.chain {
  display: flex;
  flex-direction: column;
  gap: 14px;
  margin-bottom: 24px;
}
.chain-box {
  background: var(--bg-soft);
  border: 1.5px solid var(--line);
  border-radius: var(--radius);
  padding: 14px;
  position: relative;
}
.chain-box.given { background: #eaf2ff; border-color: var(--navy-500); }
.chain-box.final { background: #fef9e7; border-color: var(--accent); }
.chain-box .box-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 8px;
}
.chain-box .box-num {
  background: var(--navy);
  color: #fff;
  font-weight: 700;
  font-size: 12px;
  padding: 3px 9px;
  border-radius: 12px;
}
.chain-box.given .box-num { background: var(--navy-500); }
.chain-box.final .box-num { background: var(--accent); color: var(--navy); }

.chain-box input,
.chain-box .given-text,
.chain-box .final-text {
  width: 100%;
  padding: 10px 12px;
  border-radius: 6px;
  border: 1px solid var(--line);
  font-size: 14px;
  font-family: inherit;
  background: #fff;
}
.chain-box .given-text,
.chain-box .final-text {
  background: transparent;
  border: none;
  padding: 4px 0;
  font-weight: 500;
}
.chain-box input:focus {
  outline: 2px solid var(--navy-500);
  outline-offset: 1px;
}

.hint-btn {
  margin-top: 8px;
  background: var(--accent-bg);
  border: 1px solid var(--accent);
  color: var(--navy);
  padding: 5px 10px;
  border-radius: 6px;
  font-size: 12px;
  cursor: pointer;
  font-family: inherit;
}
.hint-btn:hover { background: var(--accent); }
.hint-btn:disabled { opacity: 0.6; cursor: wait; }

.hint-bubble {
  margin-top: 8px;
  padding: 8px 12px;
  background: var(--accent-bg);
  border-left: 3px solid var(--accent);
  border-radius: 4px;
  font-size: 14px;
  color: var(--navy-700);
  display: none;
}
.hint-bubble.visible { display: block; }

.chain-arrow {
  text-align: center;
  color: var(--navy-500);
  font-size: 20px;
  line-height: 1;
  margin: -4px 0;
  user-select: none;
}

/* ---------- Feedback (Step 3) ---------- */
.feedback-card {
  background: var(--bg-soft);
  border-radius: var(--radius);
  padding: 16px 18px;
  margin-bottom: 14px;
  border-left: 4px solid var(--navy-500);
}
.feedback-card h3 {
  margin: 0 0 10px;
  font-size: 16px;
  color: var(--navy);
}
.feedback-body {
  font-size: 14px;
  white-space: pre-wrap;
}
.feedback-body ul { padding-left: 20px; margin: 6px 0; }

/* ---------- Samples (Step 4) ---------- */
.sample-card {
  background: #fff;
  border: 1.5px solid var(--line);
  border-radius: var(--radius);
  margin-bottom: 14px;
  overflow: hidden;
}
.sample-card summary {
  list-style: none;
  cursor: pointer;
  padding: 14px 18px;
  background: var(--bg-soft);
  display: flex;
  align-items: center;
  gap: 12px;
  font-weight: 600;
  color: var(--navy);
}
.sample-card summary::-webkit-details-marker { display: none; }
.sample-card.lv3 summary { border-bottom: 2px solid #b0c4de; }
.sample-card.lv5 summary { border-bottom: 2px solid var(--accent); }

.badge {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 12px;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.5px;
}
.badge-lv3 { background: #b0c4de; color: var(--navy); }
.badge-lv5 { background: var(--accent); color: var(--navy); }

.sample-body {
  padding: 18px;
  position: relative;
}
.sample-body > div:first-child {
  white-space: pre-wrap;
  font-size: 14.5px;
  line-height: 1.7;
  margin-bottom: 12px;
}
.copy-btn {
  margin-top: 4px;
}

/* ---------- Loading / Utility ---------- */
.hidden { display: none !important; }

.loading {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 20px;
  color: var(--muted);
}
.spinner {
  width: 20px; height: 20px;
  border: 2.5px solid var(--line);
  border-top-color: var(--navy);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ---------- Footer ---------- */
.site-footer {
  margin-top: 40px;
  padding: 20px 0;
  text-align: center;
  color: var(--muted);
  font-size: 13px;
}

/* ---------- Mobile ---------- */
@media (max-width: 600px) {
  .site-title { font-size: 22px; }
  .step-panel { padding: 18px; }
  .step .label { display: none; }
  .step { min-width: 50px; flex: 0 0 auto; }
  .step.active .label { display: inline; }
  .chip { font-size: 13px; padding: 7px 12px; }
  .btn { width: 100%; }
  .btn.ghost { width: auto; }
}