:root {
    --primary: #2563eb;
    --primary-hover: #1d4ed8;
    --bg: #f3f4f6;
    --card-bg: #ffffff;
    --text: #1f2937;
    --border: #e5e7eb;
}
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background-color: var(--bg);
    color: var(--text);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    padding: 20px;
}
.container {
    background-color: var(--card-bg);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    width: 100%;
    max-width: 500px;
}
.card {
    background-color: var(--card-bg);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    text-align: center;
    max-width: 400px;
    width: 100%;
}
h1 {
    margin-top: 0;
    margin-bottom: 1.5rem;
    text-align: center;
    font-size: 1.5rem;
    color: var(--text);
}
h2 {
    color: #059669; 
    margin-top: 0;
}
.form-group {
    margin-bottom: 1rem;
}
label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    font-size: 0.875rem;
}
input[type="text"],
input[type="number"],
input[type="file"] {
    width: 100%;
    padding: 0.5rem;
    border: 1px solid var(--border);
    border-radius: 6px;
    box-sizing: border-box;
    font-size: 1rem;
}
.hint {
    font-size: 0.75rem;
    color: #6b7280;
    margin-top: 0.25rem;
}
button {
    width: 100%;
    background-color: var(--primary);
    color: white;
    padding: 0.75rem;
    border: none;
    border-radius: 6px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: background-color 0.2s;
    margin-top: 1rem;
}
button:hover {
    background-color: var(--primary-hover);
}
button:disabled {
    background-color: #9ca3af;
    cursor: not-allowed;
}
#loading {
    display: none;
    text-align: center;
    margin-top: 1rem;
}
.spinner {
    border: 4px solid #f3f3f3;
    border-top: 4px solid var(--primary);
    border-radius: 50%;
    width: 30px;
    height: 30px;
    animation: spin 1s linear infinite;
    margin: 0 auto 0.5rem auto;
}
@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}
.btn {
    display: inline-block;
    background: var(--primary);
    color: white;
    padding: 0.75rem 1.5rem;
    text-decoration: none;
    border-radius: 6px;
    margin-top: 1rem;
    transition: 0.2s;
}
.btn:hover {
    background: var(--primary-hover);
}
.secondary {
    background: #e5e7eb;
    color: #374151;
    margin-left: 0.5rem;
}
.secondary:hover {
    background: #d1d5db;
}