:root {
    --primary-color: #007bff;
    --secondary-color: #6c757d;
    --success-color: #28a745;
    --light-color: #f8f9fa;
    --dark-color: #343a40;
    --background-color: #f4f7f6;
    --card-bg-color: #ffffff;
    --text-color: #212529;
    --border-color: #dee2e6;
    --border-radius: 8px;
    --box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

body {
    font-family: 'Roboto', sans-serif;
    margin: 0;
    background-color: var(--background-color);
    color: var(--text-color);
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

header {
    background: var(--primary-color);
    color: white;
    padding: 20px 0;
    text-align: center;
    border-bottom: 5px solid #0056b3;
}

h1, h2 {
    color: var(--dark-color);
}

.card {
    background: var(--card-bg-color);
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    padding: 25px;
    margin-bottom: 25px;
}

.hidden { display: none !important; }

/* Upload Area */
#upload-container { max-width: 800px; margin: 0 auto; }
#drop-zone {
    border: 2px dashed var(--border-color);
    border-radius: var(--border-radius);
    padding: 40px;
    text-align: center;
    cursor: pointer;
    transition: background-color 0.3s, border-color 0.3s;
}
#drop-zone.dragover {
    background-color: #e9ecef;
    border-color: var(--primary-color);
}

/* Two-Column Workspace Layout */
#tool-workspace {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 25px;
    align-items: start;
}

@media (max-width: 992px) {
    #tool-workspace {
        grid-template-columns: 1fr;
    }
}

/* FIXED: Preview Card Styles for Medium Thumbnail */
#preview-card {
    position: sticky; /* Make preview stick on scroll */
    top: 20px;
}
#preview-container {
    position: relative;
    width: 100%;
    max-width: 450px; /* Set a max-width for thumbnail appearance */
    margin: 0 auto; /* Center the container */
    background-color: #e9ecef;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    overflow: hidden;
}
#pdf-preview-canvas {
    width: 100%;
    height: auto;
    display: block;
}
#watermark-preview-overlay {
    position: absolute;
    transform-origin: center center;
    pointer-events: none;
    font-weight: bold;
    word-break: break-word;
    text-align: center;
    line-height: 1;
    transition: all 0.2s ease-in-out;
}
#file-info {
    margin-top: 15px;
    font-size: 0.9rem;
    color: var(--secondary-color);
    text-align: center;
}

/* Form & Control Styles */
.tabs { display: flex; border-bottom: 1px solid var(--border-color); margin-bottom: 20px; }
.tab-link { background: none; border: none; padding: 10px 15px; cursor: pointer; font-size: 1rem; position: relative; color: var(--secondary-color); }
.tab-link.active { color: var(--primary-color); font-weight: 700; }
.tab-link.active::after { content: ''; position: absolute; bottom: -1px; left: 0; width: 100%; height: 3px; background-color: var(--primary-color); }
.form-group { margin-bottom: 15px; }
.form-group label { display: block; margin-bottom: 8px; font-weight: 500; }
input, select { width: 100%; padding: 10px; border: 1px solid var(--border-color); border-radius: 4px; box-sizing: border-box; background-color: #fff; font-family: inherit; font-size: 1rem; }
input[type="color"] { height: 40px; padding: 5px; }
input[type="range"] { padding: 0; }
.grid-container-small { display: grid; grid-template-columns: 1fr 1fr; gap: 15px; }

/* FIXED: Compact Position Grid */
.position-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 4px; }
.pos-btn { padding: 6px; border: 1px solid var(--border-color); background-color: #fff; cursor: pointer; border-radius: 4px; transition: all 0.2s; font-size: 0.75rem; }
.pos-btn.active { background-color: var(--primary-color); color: white; border-color: var(--primary-color); }

/* Action Buttons & Indicators */
.action-buttons { display: flex; gap: 10px; }
.action-buttons .btn { flex-grow: 1; }
#processing-indicator { display: flex; align-items: center; justify-content: center; gap: 15px; margin-bottom: 20px; }
.spinner { border: 4px solid rgba(0, 0, 0, 0.1); width: 28px; height: 28px; border-radius: 50%; border-left-color: var(--primary-color); animation: spin 1s ease infinite; }
@keyframes spin { 100% { transform: rotate(360deg); } }
.btn { display: inline-block; width: 100%; padding: 12px 24px; border: none; border-radius: var(--border-radius); cursor: pointer; font-size: 1rem; font-weight: 500; text-decoration: none; text-align: center; transition: background-color 0.3s, transform 0.1s; box-sizing: border-box; }
.btn-primary { background-color: var(--primary-color); color: white; }
.btn-primary:hover { background-color: #0056b3; }
.btn-secondary { background-color: var(--secondary-color); color: white; }
.btn-secondary:hover { background-color: #5a6268; }
.btn-success { background-color: var(--success-color); color: white; margin-top: 15px; }
.btn-success:hover { background-color: #218838; }

/* SEO Article Styles */
#seo-article { margin-top: 40px; max-width: 800px; line-height: 1.7; }
#seo-article h2, #seo-article h3 { color: var(--dark-color); border-bottom: 2px solid var(--primary-color); padding-bottom: 5px; margin-top: 30px; margin-bottom: 15px; }
#seo-article h3 { border-bottom: none; color: var(--primary-color); }
#seo-article ul, #seo-article ol { padding-left: 25px; }
#seo-article li { margin-bottom: 10px; }

footer { text-align: center; padding: 20px; margin-top: 40px; color: var(--secondary-color); font-size: 0.9rem; }