:root {
    /* Light Mode (Default) */
    --primary-color: #4f46e5;
    --primary-hover: #4338ca;
    --secondary-color: #10b981;

    --bg-color: #f3f4f6;
    --card-bg: #ffffff;
    --text-color: #1f2937;
    --text-muted: #6b7280;

    --header-footer-bg: #1f2937;
    --header-footer-text: #ffffff;

    --border-color: #e5e7eb;
    --input-bg: #f9fafb;
    --input-border: #d1d5db;

    --glass-bg: rgba(255, 255, 255, 0.8);
    --glass-border: rgba(255, 255, 255, 0.5);

    --shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.05), 0 4px 6px -2px rgba(0, 0, 0, 0.025);
    --shadow-hover: 0 20px 25px -5px rgba(0, 0, 0, 0.05), 0 10px 10px -5px rgba(0, 0, 0, 0.02);
}

.dark-mode {
    /* Dark Mode Overrides */
    --primary-color: #6366f1;
    --primary-hover: #818cf8;

    --bg-color: #111827;
    --card-bg: #1f2937;
    --text-color: #f3f4f6;
    --text-muted: #9ca3af;

    --header-footer-bg: #0f172a;
    --header-footer-text: #f3f4f6;

    --border-color: #334155;
    --input-bg: #0f172a;
    --input-border: #334155;

    --glass-bg: rgba(30, 41, 59, 0.8);
    --glass-border: rgba(255, 255, 255, 0.05);

    --shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.3), 0 4px 6px -2px rgba(0, 0, 0, 0.2);
}

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

header {
    height: 80px;
    background-color: var(--header-footer-bg);
    color: var(--header-footer-text);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 2rem;
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    box-sizing: border-box;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
}

main {
    margin-top: 80px;
    padding: 2rem;
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 100%;
    box-sizing: border-box;
}

.card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 1.5rem;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05); /* Softer shadow */
    max-width: 800px;
    width: 100%;
    margin: 1rem auto;
    transition: transform 0.2s, box-shadow 0.2s;
    box-sizing: border-box; /* Fix padding issues */
}

h1, h2, h3 { color: var(--text-color); }
h1 { margin-top: 0; font-size: 1.8rem; margin-bottom: 1rem; }

.btn {
    display: flex; /* Flex for centering icon/text */
    align-items: center;
    justify-content: center;
    padding: 18px 24px; /* Larger touch area */
    border: none;
    border-radius: 12px; /* Smoother corners */
    background: linear-gradient(135deg, var(--primary-color), var(--primary-hover));
    color: white;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    text-decoration: none;
    box-shadow: 0 4px 12px rgba(79, 70, 229, 0.3); /* Colored shadow */
    transition: transform 0.1s, box-shadow 0.2s;
    width: 100%; /* Full width on mobile */
    box-sizing: border-box;
}
.btn:hover { filter: brightness(1.1); }
.btn:active { transform: scale(0.97); }

.btn-secondary { 
    background: linear-gradient(135deg, var(--secondary-color), #059669); 
    box-shadow: 0 4px 12px rgba(16, 185, 129, 0.3);
}

.action-buttons {
    display: flex;
    gap: 15px;
    margin-bottom: 30px;
    width: 100%;
    flex-wrap: wrap; /* Wrap on small screens */
}

.action-buttons .btn {
    flex: 1; /* Grow to fill space */
    min-width: 140px;
}

.recent-list {
    width: 100%;
    max-width: 600px;
}

.scan-item {
    background-color: var(--card-bg);
    padding: 16px;
    margin-bottom: 12px;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 4px rgba(0,0,0,0.02);
    transition: background-color 0.2s;
}
.scan-item:active { background-color: var(--bg-color); }

.scan-info h3 { margin: 0 0 4px 0; font-size: 1.1rem; font-weight: 600; }
.scan-info p { margin: 0; font-size: 0.9rem; color: var(--text-muted); }
.status { 
    font-size: 0.8rem; 
    padding: 4px 10px; 
    border-radius: 20px; 
    background: var(--input-bg); 
    border: 1px solid var(--border-color); 
    color: var(--text-muted);
}

/* Header Elements from reference */
header .center {
    font-weight: bold;
    font-size: 1.2rem;
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
}