@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap');

:root {
    --primary: #2563eb;
    --primary-hover: #1d4ed8;
    --secondary: #64748b;
    --background: #f8fafc;
    --surface: #ffffff;
    --text: #1e293b;
    --text-light: #64748b;
    --border: #e2e8f0;
    --success: #22c55e;
    --error: #ef4444;
    --warning: #f59e0b;
    --info: #3b82f6;
    --radius: 12px;
    --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
}

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

body {
    font-family: 'Inter', -apple-system, sans-serif;
    background-color: var(--background);
    color: var(--text);
    line-height: 1.5;
    padding: 40px 20px;
}

#app-container {
    max-width: 900px;
    margin: 0 auto;
}

h1 {
    font-size: 2.25rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 2rem;
    color: var(--text);
    letter-spacing: -0.025em;
}

.step-card {
    background: var(--surface);
    border-radius: var(--radius);
    padding: 24px;
    margin-bottom: 24px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border);
}

.step-header {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 20px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--border);
}

.step-number {
    background: var(--primary);
    color: white;
    width: 28px;
    height: 28px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 0.875rem;
}

.step-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text);
}

.info-box {
    background-color: #eff6ff;
    border: 1px solid #bfdbfe;
    padding: 20px;
    margin-bottom: 24px;
    border-radius: var(--radius);
    font-size: 0.9375rem;
}

.info-box b { color: var(--primary); }
.info-box ol, .info-box ul { padding-left: 20px; margin: 10px 0; }
.info-box li { margin-bottom: 4px; }

.config-grid, .options-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
}

@media (max-width: 640px) {
    .config-grid, .options-grid { grid-template-columns: 1fr; }
}

label {
    font-weight: 500;
    font-size: 0.875rem;
    color: var(--text);
    margin-bottom: 6px;
    display: block;
}

input[type="text"],
input[type="number"],
textarea,
select {
    width: 100%;
    padding: 10px 12px;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 0.9375rem;
    font-family: inherit;
    transition: border-color 0.2s, box-shadow 0.2s;
    background-color: white;
}

input:focus, textarea:focus, select:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

textarea { resize: vertical; }

.button, button {
    background-color: var(--primary);
    color: white;
    padding: 10px 20px;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 0.9375rem;
    font-weight: 500;
    transition: all 0.2s;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.button:hover:not(:disabled), button:hover:not(:disabled) {
    background-color: var(--primary-hover);
    transform: translateY(-1px);
}

.button:active:not(:disabled), button:active:not(:disabled) {
    transform: translateY(0);
}

button:disabled {
    background-color: var(--border);
    color: var(--text-light);
    cursor: not-allowed;
}

#clear-key-button { background-color: #f1f5f9; color: var(--text); border: 1px solid var(--border); }
#clear-key-button:hover:not(:disabled) { background-color: #e2e8f0; }

#drop-area {
    border: 2px dashed var(--border);
    border-radius: var(--radius);
    padding: 40px 20px;
    text-align: center;
    background-color: #fcfcfd;
    transition: all 0.2s;
    cursor: pointer;
}

#drop-area.highlight {
    border-color: var(--primary);
    background-color: #eff6ff;
}

.file-item {
    background: #f8fafc;
    border: 1px solid var(--border);
    padding: 12px 16px;
    border-radius: 8px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 12px;
}

#progress-area {
    margin-top: 24px;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background-color: var(--border);
    border-radius: 999px;
    overflow: hidden;
    margin-top: 12px;
}

.progress-bar-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary), #60a5fa);
    transition: width 0.4s ease;
}

.error-message {
    background-color: #fef2f2;
    border: 1px solid #fecaca;
    color: var(--error);
    padding: 12px 16px;
    border-radius: 8px;
    margin: 16px 0;
    font-size: 0.875rem;
}

#download-area a {
    display: block;
    background-color: var(--success);
    color: white;
    text-align: center;
    padding: 14px;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    margin-top: 16px;
    transition: opacity 0.2s;
}

#download-area a:hover { opacity: 0.9; }

.collapsible {
    background-color: transparent;
    color: var(--primary);
    padding: 12px 0;
    font-weight: 600;
    font-size: 1rem;
    border: none;
    text-align: left;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
}

.collapsible::after {
    content: '▼';
    font-size: 0.75rem;
    transition: transform 0.2s;
}

.collapsible.active::after { transform: rotate(180deg); }

.content {
    display: none;
    padding-bottom: 20px;
}

#stats-area {
    background: #f8fafc;
    border-radius: 8px;
    padding: 16px;
    font-size: 0.875rem;
}

#stats-area h3 { margin-bottom: 12px; font-size: 1.1rem; }
#stats-area ul { padding-left: 20px; }
#stats-area li { margin-bottom: 6px; }

.action-section {
    text-align: center;
    padding: 20px 0;
}

#generate-button {
    padding: 14px 40px;
    font-size: 1.1rem;
    box-shadow: 0 10px 15px -3px rgba(37, 99, 235, 0.4);
}

.radio-group {
    background: #f8fafc;
    padding: 12px;
    border-radius: 8px;
    border: 1px solid var(--border);
}

.radio-option {
    display: flex;
    align-items: flex-start;
    gap: 8px;
    margin-bottom: 8px;
}

.radio-option:last-child { margin-bottom: 0; }

.radio-option input { margin-top: 4px; }

.badge-info {
    font-size: 0.75rem;
    color: var(--text-light);
    margin-top: 4px;
    display: block;
}