:root {
  --primary: #0381fe; /* Samsung Blue */
  --bg-color: #f2f2f2;
  --surface-color: #ffffff;
  --text-primary: #000000;
  --text-secondary: #555555;
  --border-radius-lg: 24px;
  --border-radius-sm: 16px;
  --spacing: 20px;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, system-ui, Roboto, 'Helvetica Neue', 'Segoe UI', 'Apple SD Gothic Neo', 'Noto Sans KR', 'Malgun Gothic', 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol', sans-serif;
}

body {
  background-color: var(--bg-color);
  color: var(--text-primary);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Mobile Container */
.app-container {
  max-width: 480px;
  margin: 0 auto;
  min-height: 100vh;
  background-color: var(--bg-color);
  position: relative;
  display: flex;
  flex-direction: column;
  box-shadow: 0 0 20px rgba(0,0,0,0.05);
}

.app-header {
  padding: 24px 24px 0;
  display: flex;
  justify-content: flex-start;
  align-items: center;
}

.app-logo {
  height: 40px;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

/* One UI Layout */
.viewing-area {
  padding: 24px 24px 20px;
  flex-shrink: 0;
}

.viewing-area h1 {
  font-size: 28px;
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: 12px;
}

.viewing-area p {
  font-size: 16px;
  color: var(--text-secondary);
}

.hero-title {
  font-size: 40px !important;
  font-weight: 800 !important;
  line-height: 1.2 !important;
  margin-bottom: 16px !important;
  letter-spacing: -1.5px;
}

.hero-title .highlight-text {
  color: var(--primary);
}

.hero-subtitle {
  font-size: 18px !important;
  color: var(--text-secondary);
  line-height: 1.5 !important;
  word-break: keep-all;
}

.hero-subtitle b {
  color: var(--text-primary);
  font-weight: 700;
}

.interaction-area {
  flex: 1;
  background-color: var(--surface-color);
  border-top-left-radius: var(--border-radius-lg);
  border-top-right-radius: var(--border-radius-lg);
  padding: 32px 24px 100px; /* space for bottom button */
  box-shadow: 0 -4px 12px rgba(0,0,0,0.02);
  display: flex;
  flex-direction: column;
  gap: 20px;
}

/* Animations */
.fade-in {
  animation: fadeIn 0.4s ease-out forwards;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Components */
.card {
  background-color: var(--bg-color);
  border-radius: var(--border-radius-sm);
  padding: 24px;
  text-align: center;
}

.card h3 {
  font-size: 18px;
  margin-bottom: 8px;
}

.card p {
  font-size: 14px;
  color: var(--text-secondary);
  margin-bottom: 16px;
}

/* Bottom Fixed Button */
.bottom-bar {
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  padding: 16px 24px 32px;
  background: linear-gradient(to top, rgba(255,255,255,1) 70%, rgba(255,255,255,0));
}

.btn-primary {
  width: 100%;
  background-color: var(--primary);
  color: white;
  border: none;
  border-radius: 100px; /* pill shape */
  padding: 16px;
  font-size: 18px;
  font-weight: 600;
  cursor: pointer;
  transition: opacity 0.2s, transform 0.1s;
}

.btn-primary:active {
  transform: scale(0.98);
  opacity: 0.9;
}

.btn-secondary {
  width: 100%;
  background-color: #e5e5ea;
  color: #000;
  border: none;
  border-radius: 100px;
  padding: 16px;
  font-size: 18px;
  font-weight: 600;
  cursor: pointer;
  transition: background-color 0.2s;
  margin-top: 12px;
}

.btn-secondary:active {
  background-color: #d1d1d6;
}

.link-btn {
  display: inline-block;
  background-color: var(--primary);
  color: white;
  text-decoration: none;
  padding: 12px 20px;
  border-radius: 100px;
  font-size: 15px;
  font-weight: 600;
  transition: opacity 0.2s;
}

.link-btn:active {
  opacity: 0.8;
}

.link-btn-outline {
  display: inline-block;
  background-color: transparent;
  color: var(--primary);
  text-decoration: none;
  padding: 12px 20px;
  border-radius: 100px;
  border: 2px solid var(--primary);
  font-size: 15px;
  font-weight: 600;
  transition: background-color 0.2s;
}

.link-btn-outline:active {
  background-color: rgba(3, 129, 254, 0.1);
}

.pdf-preview {
  width: 100%;
  max-width: 200px;
  height: auto;
  border-radius: 8px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
  margin: 0 auto 16px;
  display: block;
  border: 1px solid #eaeaea;
}

.btn-group {
  display: flex;
  gap: 10px;
  justify-content: center;
  margin-top: 10px;
  flex-wrap: wrap;
}