:root {
    --primary: #ff5722; /* Orange accent */
    --success: #28a745;
    --bg: #fff7ed;      /* Very light orange tint */
    --dark-grey: #333;
    --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

body {
    font-family: var(--font-family);
    background-color: var(--bg);
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 20px;
    margin: 0;
}

/* Navigation Link Style */
nav {
    width: 100%;
    max-width: 400px;
    margin-bottom: 20px;
    text-align: left;
}

.nav-link {
    text-decoration: none;
    color: #666;
    font-weight: 600;
    font-size: 0.9rem;
    transition: color 0.2s;
}

.nav-link:hover {
    color: var(--primary);
}

/* Main Card */
main {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 10px 25px -5px rgba(0,0,0,0.1);
    text-align: center;
    width: 100%;
    max-width: 400px;
    border-top: 6px solid var(--primary); /* Orange top border */
}

h2 {
    margin-top: 0;
    color: var(--dark-grey);
}

#file-input {
    display: none;
}

.file-label {
    display: inline-block;
    background: var(--primary);
    color: white;
    padding: 12px 24px;
    border-radius: 6px;
    cursor: pointer;
    font-weight: 500;
    margin-bottom: 1rem;
    transition: background 0.2s;
}

.file-label:hover {
    background: #e64a19;
}

#file-name {
    display: block;
    margin-bottom: 1.5rem;
    color: #6c757d;
    font-style: italic;
    font-size: 0.9rem;
}

#upload-button {
    background: var(--dark-grey);
    color: white;
    padding: 14px;
    width: 100%;
    border: none;
    border-radius: 6px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.1s;
}

#upload-button:active {
    transform: scale(0.98);
}

/* Status Messages */
#status {
    margin-top: 20px;
    font-size: 0.9rem;
    min-height: 1.2em;
}
.status-success { color: var(--success); }
.status-error { color: #dc3545; }
.status-info { color: #555; }

/* Shake Animation for Download Button */
@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-5px) rotate(-5deg); }
    75% { transform: translateX(5px) rotate(5deg); }
}

.shake-animation {
    animation: shake 0.4s ease-in-out;
}