:root {
    /* Core Brand Palette */
    --primary: #2563EB;
    --primary-dark: #1D4ED8;
    --danger: #EF4444;
    --success-soft: #D1FAE5;
    --gray-light: #F3F4F6;
    --gray-mid: #9CA3AF;
    --gray-dark: #1F2937;
    
    /* Layout & Shadow */
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -1px rgba(0,0,0,0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1), 0 4px 6px -2px rgba(0,0,0,0.05);
    --nav-shadow: rgba(0, 0, 0, 0.05);

    /* Typography */
    --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

/* Global Reset & Typography */
body {
    font-family: var(--font-sans);
    color: var(--gray-dark);
    background-color: #f9fafb;
    margin: 0;
}

h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    color: #111827;
}

a {
    color: var(--primary);
    transition: all 0.2s ease;
    text-decoration: none;
    font-weight: 500;
}

a:hover {
    color: var(--primary-dark);
    text-decoration: underline;
}

/* Common Layout Components */
.main-window {
    width: 100%;
    background: #fff;
    padding: 1.5rem;
    border-radius: 0.75rem;
    margin: 0.5rem;
    text-align: center;
    font-weight: 700;
    font-size: 1.1rem;
    border: 1px solid #e5e7eb;
    box-shadow: var(--shadow-md);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    display: inline-block;
}

.main-window:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary);
    color: var(--primary);
}

/* QR Code System */
.qr-code-generator {
    width: 100%;
    max-width: 500px;
    margin: 0 auto;
}

#qrcode {
    width: 128px;
    height: 128px;
    margin: 1rem auto;
    text-align: center;
}

.qr-input-group {
    display: flex;
    gap: 0.5rem;
}

.qr-url { flex: 4; }
.qr-size { flex: 1; }

.qr-url, .qr-size {
    padding: 0.5rem;
    border: 1px solid #d1d5db;
    border-radius: 0.375rem;
    transition: border-color 0.2s;
}

.qr-url:focus, .qr-size:focus {
    border-color: var(--primary);
    outline: none;
}

.generate-qr-code {
    display: block;
    width: 100%;
    margin-top: 0.75rem;
    padding: 0.5rem;
    font-size: 1.1rem;
    font-weight: 600;
    border: none;
    border-radius: 0.375rem;
    cursor: pointer;
    background-color: var(--danger);
    color: #fff;
    transition: opacity 0.2s;
}

.generate-qr-code:hover {
    opacity: 0.9;
}

/* Navigation & Share Bars */
.navbar-share .nav-item {
    margin: 0 0.25rem;
    border-radius: 0.5rem;
    padding: 0.25rem;
    background: var(--gray-light);
    box-shadow: var(--shadow-sm);
}

.navbar-share .dropdown-item {
    border-radius: 0.375rem;
    transition: background-color 0.2s;
}

/* Custom UI Elements */
.swal-overlay {
    background-color: var(--success-soft);
}

.my-button-class {
    background-color: var(--danger);
    color: white;
    border-radius: 0.375rem;
    font-weight: 600;
    border: none;
    padding: 0.5rem 1rem;
}

#imgGithub { width: 32px; height: 32px; object-fit: cover; border-radius: 50%; }
#imgGoogle { width: 32px; height: 32px; object-fit: cover; border-radius: 50%; }

.navbar-profile-img {
    width: 32px;
    height: 32px;
    object-fit: cover;
    border-radius: 50%;
    border: 1px solid rgba(255,255,255,0.2);
}

/* Tooltip System */
.tooltip_custom {
    position: relative;
    display: inline-block;
    border-bottom: 1px dotted var(--gray-mid);
}

.tooltip_custom .tooltiptext {
    visibility: hidden;
    background-color: #fff;
    color: var(--gray-dark);
    text-align: left;
    border-radius: 0.5rem;
    padding: 0.75rem;
    position: absolute;
    z-index: 100;
    bottom: 125%;
    left: 50%;
    transform: translateX(-50%);
    opacity: 0;
    transition: opacity 0.3s;
    min-width: 150px;
    box-shadow: var(--shadow-lg);
    border: 1px solid #e5e7eb;
}

.tooltip_custom .tooltiptext::after {
    content: "";
    position: absolute;
    top: 100%;
    left: 50%;
    margin-left: -5px;
    border-width: 5px;
    border-style: solid;
    border-color: #fff transparent transparent transparent;
}

.tooltip_custom:hover .tooltiptext {
    visibility: visible;
    opacity: 1;
}

/* Modern Table Enhancements */
caption {
    background: #79b1d3;
    color: #fff;
    caption-side: top;
    text-align: center;
    padding: 0.75rem;
    font-size: 1.5rem;
    font-weight: 700;
    border-radius: 0.5rem 0.5rem 0 0;
}