body {
  margin: 0;
  font-family: Arial, "Noto Sans KR", sans-serif;
  background: #f4f6f8;
  color: #101828;
}

header {
  background: #111827;
  color: white;
  padding: 20px;
  display: flex;
  gap: 20px;
  align-items: center;
}

header h1 {
  margin: 0;
  width: 220px;
}

header button {
  flex: 1;
}

main {
  padding: 16px;
  display: grid;
  gap: 16px;
}

.box {
  background: white;
  border-radius: 18px;
  padding: 18px;
  box-shadow: 0 8px 24px rgba(0,0,0,0.08);
}

.drop-zone {
  height: 180px;
  border: 2px dashed #9aa8bd;
  border-radius: 16px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  cursor: pointer;
  margin-bottom: 12px;
}

.drop-zone.dragover {
  background: #eef6ff;
  border-color: #1f6feb;
}

input, textarea, button {
  width: 100%;
  margin-top: 8px;
  border-radius: 12px;
  font-size: 15px;
  box-sizing: border-box;
}

input, button {
  height: 44px;
}

input, textarea {
  border: 1px solid #d0d5dd;
  padding: 10px;
}

textarea {
  height: 80px;
  resize: vertical;
}

button {
  border: none;
  background: #1f6feb;
  color: white;
  font-weight: bold;
  cursor: pointer;
}

.pdf-card {
  border: 1px solid #e3e8ef;
  border-radius: 14px;
  padding: 14px;
  margin-top: 10px;
  cursor: pointer;
  background: white;
}

.pdf-card:hover {
  background: #f8fbff;
}

.pdf-title {
  font-weight: bold;
  font-size: 16px;
}

.meta {
  color: #667085;
  font-size: 13px;
  margin-top: 5px;
}

.comment {
  margin-top: 10px;
  padding: 10px;
  background: #f2f4f7;
  border-radius: 10px;
  white-space: pre-wrap;
}

.new {
  display: inline-block;
  background: #ff3b30;
  color: white;
  font-size: 12px;
  font-weight: bold;
  padding: 4px 8px;
  border-radius: 999px;
  margin-left: 8px;
}

.viewer-comment {
  margin: 10px 0;
  padding: 12px;
  background: #f2f4f7;
  border-radius: 12px;
  white-space: pre-wrap;
  display: none;
}

.viewer iframe {
  width: 100%;
  height: 75vh;
  border: 1px solid #ddd;
  border-radius: 14px;
}
.open-pdf-btn {
  display: none;
  width: 100%;
  margin: 10px 0;
  padding: 14px;
  text-align: center;
  background: #1f6feb;
  color: white;
  font-weight: bold;
  border-radius: 12px;
  text-decoration: none;
}

@media (max-width: 768px) {
  .open-pdf-btn {
    display: block;
  }

  .viewer iframe {
    display: none;
  }
}