:root {
    --bg-color: #f8fafc;
    --card-bg: #ffffff;
    --text-primary: #0f172a;
    --text-secondary: #64748b;
    --primary: #4f46e5;
    --primary-hover: #4338ca;
    --border-color: #e2e8f0;
    --success: #10b981;
    --error: #ef4444;
    --error-bg: #fef2f2;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --radius-md: 0.5rem;
    --radius-lg: 1rem;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

.app-container {
    max-width: 800px;
    margin: 0 auto;
    padding: 2rem;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;
    flex-wrap: wrap;
    padding-bottom: 2rem;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--primary);
}

.header-badges {
    display: flex;
    flex-wrap: wrap;
    justify-content: flex-end;
    gap: 0.5rem;
}

.badge {
    display: inline-flex;
    align-items: center;
}

.privacy-badge {
    background: #ecfdf5;
    color: #047857;
    padding: 0.25rem 0.75rem;
    border-radius: 9999px;
    font-size: 0.75rem;
    font-weight: 600;
    border: 1px solid #d1fae5;
}

.github-badge {
    background-color: var(--card-bg);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    padding: 0.25rem 0.75rem;
    border-radius: 9999px;
    font-size: 0.75rem;
    font-weight: 600;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    transition: all 0.2s ease;
    cursor: pointer;
}

.github-badge:hover {
    background-color: var(--bg-color);
    border-color: var(--primary);
    color: var(--primary);
}

.author-badge {
    background-color: var(--card-bg);
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
    padding: 0.25rem 0.75rem;
    border-radius: 9999px;
    font-size: 0.75rem;
    font-weight: 600;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    transition: all 0.2s ease;
    cursor: pointer;
}

.author-badge:hover {
    background-color: var(--bg-color);
    border-color: var(--primary);
    color: var(--primary);
}

main {
    flex-grow: 1;
}

.hero {
    text-align: center;
    margin-bottom: 3rem;
}

.hero h1 {
    font-size: 2.5rem;
    font-weight: 800;
    letter-spacing: -0.025em;
    margin-bottom: 1rem;
    background: linear-gradient(135deg, var(--text-primary), var(--primary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero p {
    font-size: 1.125rem;
    color: var(--text-secondary);
}

.trust-callout {
    margin-top: 1rem;
    font-size: 0.9rem !important;
    color: #047857 !important;
    background: #ecfdf5;
    border: 1px solid #d1fae5;
    border-radius: var(--radius-md);
    padding: 0.75rem 1.25rem;
    display: inline-block;
    max-width: 600px;
    line-height: 1.6;
}

.trust-callout code,
.compatibility-note code {
    font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
    font-size: 0.92em;
    background: rgba(15, 23, 42, 0.06);
    color: inherit;
    padding: 0.1rem 0.35rem;
    border-radius: 0.35rem;
}

.hero-links {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin-top: 1rem;
}

.hero-link {
    text-decoration: none;
    color: var(--text-primary);
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 9999px;
    padding: 0.55rem 0.95rem;
    font-size: 0.875rem;
    font-weight: 600;
    transition: all 0.2s ease;
}

.hero-link:hover {
    border-color: var(--primary);
    color: var(--primary);
    background: #fbfbfe;
}

.hero-link-primary {
    background: var(--primary);
    color: #ffffff;
    border-color: var(--primary);
    box-shadow: 0 4px 10px rgba(79, 70, 229, 0.18);
}

.hero-link-primary:hover {
    background: var(--primary-hover);
    border-color: var(--primary-hover);
    color: #ffffff;
}

.compatibility-note {
    margin-top: 1rem;
    font-size: 0.88rem !important;
    color: var(--text-secondary) !important;
}

.drop-zone {
    background: var(--card-bg);
    border: 2px dashed var(--border-color);
    border-radius: var(--radius-lg);
    padding: 4rem 2rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.2s ease;
    position: relative;
    box-shadow: var(--shadow-sm);
    margin-bottom: 2rem;
}

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

.file-input {
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    opacity: 0;
    cursor: pointer;
}

.upload-icon {
    width: 48px;
    height: 48px;
    color: var(--primary);
    margin-bottom: 1rem;
}

.drop-zone-content h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.drop-zone-content p {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.hidden {
    display: none !important;
}

.mapping-section {
    background: var(--card-bg);
    border-radius: var(--radius-lg);
    padding: 2rem;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
    animation: fadeIn 0.4s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.mapping-section h2 {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.section-desc {
    color: var(--text-secondary);
    margin-bottom: 2rem;
    font-size: 0.95rem;
}

.mapping-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.mapping-row {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.mapping-row label, .setting-row label {
    font-weight: 500;
    font-size: 0.875rem;
    color: var(--text-primary);
}

.required {
    color: var(--error);
}

select, input {
    appearance: none;
    -webkit-appearance: none;
    background-color: var(--bg-color);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 0.75rem 1rem;
    font-size: 0.875rem;
    color: var(--text-primary);
    font-family: inherit;
    transition: border-color 0.2s, box-shadow 0.2s;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 24 24' stroke='%2364748b'%3E%3Cpath stroke-linecap='round' stroke-linejoin='round' stroke-width='2' d='M19 9l-7 7-7-7'%3E%3C/path%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 0.75rem center;
    background-size: 1rem;
}

input {
    background-image: none;
}

select:focus, input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

.advanced-settings {
    margin-bottom: 2rem;
    border-top: 1px solid var(--border-color);
    padding-top: 1.5rem;
}

details {
    cursor: pointer;
}

summary {
    font-weight: 500;
    color: var(--text-secondary);
    font-size: 0.875rem;
    outline: none;
    user-select: none;
}

.settings-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 1rem;
    margin-top: 1rem;
    animation: fadeIn 0.3s ease;
}

.setting-row {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.action-footer {
    display: flex;
    gap: 1rem;
    border-top: 1px solid var(--border-color);
    padding-top: 1.5rem;
}

button {
    font-family: inherit;
    font-weight: 600;
    font-size: 0.95rem;
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all 0.2s;
    border: none;
}

.primary-btn {
    background: var(--primary);
    color: white;
    flex-grow: 1;
    box-shadow: 0 4px 6px -1px rgba(79, 70, 229, 0.2);
}

.primary-btn:hover {
    background: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: 0 6px 8px -1px rgba(79, 70, 229, 0.3);
}

.primary-btn:active {
    transform: translateY(0);
}

.secondary-btn {
    background: white;
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
}

.secondary-btn:hover {
    background: var(--bg-color);
    color: var(--text-primary);
}

.error-message {
    margin-top: 1rem;
    padding: 1rem;
    background: var(--error-bg);
    color: var(--error);
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    border: 1px solid #fecaca;
}

footer {
    text-align: center;
    padding-top: 2rem;
    color: var(--text-secondary);
    font-size: 0.875rem;
}

footer a {
    color: var(--primary);
    text-decoration: none;
    transition: color 0.2s ease;
}

footer a:hover {
    color: var(--primary-hover);
    text-decoration: underline;
}

@media (max-width: 720px) {
    .app-container {
        padding: 1.25rem;
    }

    header,
    .header-badges,
    .action-footer {
        flex-direction: column;
        align-items: stretch;
    }

    .hero h1 {
        font-size: 2rem;
    }

    .trust-callout {
        display: block;
        max-width: none;
    }

    .hero-link {
        text-align: center;
    }
}