:root {
    --primary-color: #4a90e2;
    --primary-dark: #047857;
    --bg-color: #f0f2f5;
    --text-color: #333;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: var(--bg-color);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    overflow-x: hidden; /* Prevents accidental scroll on mobile */

    align-items: center;

}

nav {
    background-color: var(--primary-dark);
    box-shadow: 0 4px 10px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-container {
    max-width: 500px;
    width: 100vw;
    margin: 0 auto;
    padding: 1rem;
    display: flex;
    justify-content: center;
    flex-wrap: wrap; /* Allows menu items to stack on small screens */
    gap: 1rem;
}

nav a {
    color: rgba(255, 255, 255, 0.95);
    text-decoration: none;
    font-weight: 500;
    font-size: 1rem;
    padding: 0.8rem 0.15rem;
    border-radius: 6px;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    gap: 16px;
    white-space: nowrap;
}

nav a:hover, nav a.active {
    background-color: rgba(255, 255, 255, 0.2);
    color: #fff;
    transform: translateY(-2px);
}

.container {
    width: 100%;
    max-width: 500px;
}

.upload-card {
    background: white;
    padding: 15px;
    border-radius: 5px;
    box-shadow: 0 10px 25px rgba(0,0,0,0.1);
    text-align: center;
}

h2 { margin-bottom: 10px; color: var(--text-color); }
p { color: #666; margin-bottom: 20px; font-size: 0.9rem; }

/* Drag and Drop Zone */
.drop-zone {
    width: 100%;
    padding: 10px;
    border: 2px dashed #cccccc;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.3s ease;
    background-color: #fafafa;
    position: relative;
}

.drop-zone:hover, .drop-zone.dragover {
    border-color: var(--primary-color);
    background-color: #eaf4ff;
}

#fileInput { display: none; }

.drop-text p { font-weight: bold; font-size: 1.1rem; margin: 0; }
.drop-text small { color: #888; }

/* Preview Styling */
.preview-container {
    margin-top: 20px;
    display: none; /* Hidden by default */
    border-radius: 8px;
    overflow: hidden;
    border: 1px solid #ddd;
}

.preview-media {
    max-width: 100%;
    max-height: 300px;
    display: block;
    margin: 0 auto;
}

/* Button */
.btn {
    width: 100%;
    padding: 12px;
    margin-top: 20px;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 1rem;
    cursor: pointer;
    transition: background 0.3s;
}

.btn:hover { background-color: #357abd; }
.btn:disabled { background-color: #ccc; cursor: not-allowed; }

/* Status Messages */
.status-message {
    margin-top: 15px;
    padding: 10px;
    border-radius: 5px;
    font-size: 0.9rem;
    display: none;
}
.success { background-color: #d4edda; color: #155724; }
.error { background-color: #f8d7da; color: #721c24; }