:root {
  --bg: #f6f7f9;
  --panel: #ffffff;
  --border: #e5e7eb;
  --text: #1a1d23;
  --text-dim: #6b7280;
  --accent: #2563eb;
  --accent-soft: #eff4ff;
  --good: #15803d;
  --good-bg: #e9f7ef;
  --mid: #b45309;
  --mid-bg: #fef3e2;
  --bad: #b91c1c;
  --bad-bg: #fdecec;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
}

.topbar {
  background: var(--panel);
  border-bottom: 1px solid var(--border);
  padding: 20px 32px;
}

.topbar h1 {
  font-size: 18px;
  margin: 0 0 14px;
}

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

.tab-btn {
  border: 1px solid var(--border);
  background: var(--panel);
  color: var(--text-dim);
  padding: 8px 16px;
  border-radius: 8px;
  cursor: pointer;
  font-size: 13.5px;
  font-weight: 600;
}

.tab-btn.active {
  background: var(--accent-soft);
  color: var(--accent);
  border-color: var(--accent);
}

main { padding: 28px 32px; max-width: 1100px; margin: 0 auto; }

.tab-panel { display: none; }
.tab-panel.active { display: block; }

.panel-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}

@media (max-width: 860px) {
  .panel-grid { grid-template-columns: 1fr; }
}

.panel-input, .panel-output {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px;
}

.panel-input h2, .panel-output h2 {
  font-size: 15px;
  margin: 0 0 6px;
}

.hint { font-size: 12.5px; color: var(--text-dim); margin: 0 0 14px; }

input[type="file"] { display: block; margin-bottom: 12px; font-size: 13px; }

textarea {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 12px;
  font-size: 13.5px;
  font-family: inherit;
  resize: vertical;
  margin-bottom: 12px;
}

button {
  background: var(--accent);
  color: #fff;
  border: none;
  padding: 10px 18px;
  border-radius: 8px;
  font-size: 13.5px;
  font-weight: 600;
  cursor: pointer;
}

button:disabled { opacity: 0.6; cursor: default; }

.status { margin-top: 10px; font-size: 12.5px; color: var(--text-dim); }
.status.error { color: var(--bad); }

.result-empty { color: var(--text-dim); font-size: 13px; }

.disc-link-btn {
  display: inline-block;
  background: var(--accent);
  color: #fff;
  text-decoration: none;
  padding: 10px 18px;
  border-radius: 8px;
  font-size: 13.5px;
  font-weight: 600;
  margin-bottom: 4px;
}

.disc-result-text {
  font-size: 13.5px;
  line-height: 1.6;
  white-space: pre-wrap;
}

.score-card .badge {
  display: inline-block;
  padding: 4px 12px;
  border-radius: 999px;
  font-size: 12.5px;
  font-weight: 700;
  margin-bottom: 12px;
}

.badge.good { background: var(--good-bg); color: var(--good); }
.badge.mid { background: var(--mid-bg); color: var(--mid); }
.badge.bad { background: var(--bad-bg); color: var(--bad); }

.score-card .diem {
  font-size: 28px;
  font-weight: 800;
  margin-bottom: 4px;
}

.score-card h3 {
  font-size: 12.5px;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  color: var(--text-dim);
  margin: 18px 0 8px;
}

.score-card ul { margin: 0; padding-left: 18px; font-size: 13px; }
.score-card li { margin-bottom: 6px; }

.score-card .criteria-item {
  margin-bottom: 8px;
  font-size: 13px;
}
.score-card .criteria-item b { display: block; font-size: 12px; color: var(--text-dim); }

.chat-wrap {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  display: flex;
  flex-direction: column;
  height: 60vh;
}

.chat-log {
  flex: 1;
  overflow-y: auto;
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.msg {
  max-width: 75%;
  padding: 10px 14px;
  border-radius: 12px;
  font-size: 13.5px;
  line-height: 1.5;
  white-space: pre-wrap;
}

.msg.user {
  align-self: flex-end;
  background: var(--accent);
  color: #fff;
}

.msg.assistant {
  align-self: flex-start;
  background: var(--accent-soft);
  color: var(--text);
}

.chat-input-row {
  display: flex;
  gap: 10px;
  padding: 16px;
  border-top: 1px solid var(--border);
}

.chat-input-row input[type="text"] {
  flex: 1;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 12px;
  font-size: 13.5px;
}

.chat-input-row input[type="file"] {
  flex: 0 0 auto;
  max-width: 160px;
  font-size: 12px;
  align-self: center;
}

@media (max-width: 640px) {
  .chat-input-row {
    flex-wrap: wrap;
  }

  .chat-input-row input[type="file"] {
    flex: 1 1 100%;
    max-width: 100%;
    order: -1;
  }

  .chat-input-row input[type="text"] {
    flex: 1 1 auto;
    min-width: 0;
  }

  .chat-input-row button {
    flex: 0 0 auto;
  }

  .chat-wrap { height: 70vh; }
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #16181d;
    --panel: #1e2128;
    --border: #2c3038;
    --text: #eceef1;
    --text-dim: #9aa0a9;
    --accent: #5b8def;
    --accent-soft: #22314f;
    --good: #34d399;
    --good-bg: #10302399;
    --mid: #fbbf24;
    --mid-bg: #3a2c0d99;
    --bad: #f87171;
    --bad-bg: #3a141499;
  }
}