:root {
    --primary-color: #2c3e50;
    --accent-color: #3498db;
    --success-color: #27ae60;
    --error-color: #c0392b;
    --bg-color: #f5f7fa;
    --card-bg: #ffffff;
}

* { box-sizing: border-box; margin: 0; padding: 0; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif; }

body { background-color: var(--bg-color); color: #333; display: flex; justify-content: center; min-height: 100vh; padding: 20px; }

.container { width: 100%; max-width: 480px; background: var(--card-bg); border-radius: 12px; box-shadow: 0 4px 15px rgba(0,0,0,0.1); overflow: hidden; display: flex; flex-direction: column; }

header { background: var(--primary-color); color: white; padding: 20px; text-align: center; }
header h1 { font-size: 1.2rem; font-weight: 500; letter-spacing: 1px; }

.content { padding: 24px; flex: 1; }

/* Home Page Specific */
.scan-instruction { text-align: center; margin-top: 40px; }
.nfc-icon { font-size: 4rem; color: var(--accent-color); margin-bottom: 20px; display: block; }
.hint { color: #666; line-height: 1.6; }

/* Book Info Styles */
.info-group { margin-bottom: 25px; }
.info-title { font-size: 0.9rem; color: #888; border-bottom: 2px solid #eee; padding-bottom: 8px; margin-bottom: 12px; font-weight: bold; text-transform: uppercase; letter-spacing: 0.5px; }

.data-row { display: flex; justify-content: space-between; margin-bottom: 10px; font-size: 0.95rem; }
.label { color: #666; min-width: 80px; }
.value { font-weight: 500; text-align: right; }

.status-badge { padding: 4px 12px; border-radius: 20px; font-size: 0.85rem; font-weight: bold; }
.status-in { background-color: #e8f8f5; color: var(--success-color); }
.status-out { background-color: #fdedec; color: var(--error-color); }

.loading { text-align: center; color: #666; padding: 40px 0; }
.error-msg { text-align: center; color: var(--error-color); padding: 20px; }

@media (max-width: 350px) {
    .data-row { flex-direction: column; margin-bottom: 15px; }
    .value { text-align: left; margin-top: 2px; }
}