* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 800px;
    margin: 0 auto;
}

header {
    text-align: center;
    color: white;
    margin-bottom: 40px;
}

header h1 {
    font-size: 2.5em;
    margin-bottom: 10px;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.1);
}

header p {
    font-size: 1.2em;
    opacity: 0.95;
}

main {
    background: white;
    padding: 40px;
    border-radius: 12px;
    box-shadow: 0 20px 60px rgba(0,0,0,0.3);
}

.form-group {
    margin-bottom: 30px;
}

label {
    display: block;
    margin-bottom: 10px;
}

.label-text {
    font-weight: 600;
    color: #333;
    font-size: 1.1em;
    display: block;
    margin-bottom: 5px;
}

.label-hint {
    font-size: 0.9em;
    color: #666;
    display: block;
}

input[type="file"] {
    width: 100%;
    padding: 12px;
    border: 2px dashed #ddd;
    border-radius: 8px;
    background: #f8f9fa;
    cursor: pointer;
    transition: all 0.3s;
}

input[type="file"]:hover {
    border-color: #667eea;
    background: #f0f2ff;
}

input[type="file"]:focus {
    outline: none;
    border-color: #667eea;
}

button {
    width: 100%;
    padding: 15px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1.1em;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
}

button:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(102, 126, 234, 0.4);
}

button:active {
    transform: translateY(0);
}

button:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}

#spinner {
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255,255,255,0.3);
    border-top-color: white;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-left: 10px;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.hidden {
    display: none !important;
}

.error-message,
.success-message {
    margin-top: 20px;
    padding: 15px;
    border-radius: 8px;
    font-weight: 500;
}

.error-message {
    background: #fee;
    color: #c33;
    border: 1px solid #fcc;
}

.success-message {
    background: #efe;
    color: #3c3;
    border: 1px solid #cfc;
}

footer {
    margin-top: 40px;
    background: white;
    padding: 30px;
    border-radius: 12px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
}

.info-section,
.example-section {
    margin-bottom: 30px;
}

footer h3 {
    color: #333;
    margin-bottom: 15px;
}

footer ol {
    margin-left: 25px;
    color: #666;
    line-height: 1.8;
}

pre {
    background: #f4f4f4;
    padding: 15px;
    border-radius: 6px;
    overflow-x: auto;
    border-left: 4px solid #667eea;
    margin: 10px 0;
}

code {
    font-family: 'Courier New', Courier, monospace;
    font-size: 0.9em;
    color: #333;
}

@media (max-width: 600px) {
    header h1 {
        font-size: 2em;
    }
    
    main {
        padding: 25px;
    }
    
    footer {
        padding: 20px;
    }
}