:root {
    --bg-color: #f8f9fa;
    --card-bg: #ffffff;
    --text-primary: #212529;
    --text-secondary: #6c757d;
    --accent-color: #3f51b5;
    --accent-hover: #303f9f;
    --border-radius: 16px;
    --transition: all 0.2s ease-in-out;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --border-color: #e9ecef;
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.5;
    min-height: 100vh;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

header {
    margin-bottom: 2.5rem;
    text-align: center;
}

.back-link {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.9rem;
    margin-bottom: 1rem;
    transition: var(--transition);
}

.back-link:hover {
    color: var(--accent-color);
}

.back-link svg {
    width: 16px;
    height: 16px;
}

h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.subtitle {
    color: var(--text-secondary);
}

.app-grid {
    display: grid;
    grid-template-columns: 400px 1fr;
    gap: 2rem;
    align-items: start;
}

.card {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}

.input-group {
    margin-bottom: 1.5rem;
}

label {
    display: block;
    font-weight: 600;
    font-size: 0.9rem;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

input[type="text"],
input[type="password"],
textarea,
select {
    width: 100%;
    padding: 0.8rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: 10px;
    font-family: inherit;
    font-size: 0.95rem;
    transition: var(--transition);
}

input:focus,
textarea:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(63, 81, 181, 0.1);
}

small {
    display: block;
    margin-top: 0.4rem;
    font-size: 0.8rem;
    color: var(--text-secondary);
}

small a {
    color: var(--accent-color);
    text-decoration: none;
}

.drop-zone {
    border: 2px dashed var(--border-color);
    border-radius: 12px;
    padding: 2rem;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    margin-bottom: 1.5rem;
    background: #fafafa;
}

.drop-zone:hover, .drop-zone.dragover {
    border-color: var(--accent-color);
    background: rgba(63, 81, 181, 0.05);
}

.drop-zone svg {
    width: 40px;
    height: 40px;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.primary-btn, .secondary-btn {
    width: 100%;
    padding: 1rem;
    border: none;
    border-radius: 10px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    margin-top: 1rem;
}

.primary-btn {
    background: var(--accent-color);
    color: white;
}

.primary-btn:hover:not(:disabled) {
    background: var(--accent-hover);
    transform: translateY(-2px);
}

.primary-btn:disabled {
    background: #ccc;
    cursor: not-allowed;
}

.button-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.5rem;
    margin-top: 0.5rem;
}

.advanced-settings {
    margin-top: 1rem;
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.advanced-settings summary {
    cursor: pointer;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.advanced-settings[open] {
    padding: 1rem;
    background: #f1f3f5;
    border-radius: 8px;
}

.caption-item {
    background: #f8f9fa;
    padding: 0.8rem;
    border-radius: 8px;
    font-size: 0.9rem;
    cursor: pointer;
    border: 1px solid transparent;
    transition: var(--transition);
}

.caption-item:hover {
    border-color: var(--accent-color);
    background: white;
}

hr {
    margin: 2rem 0;
    border: 0;
    border-top: 1px solid var(--border-color);
}

.style-controls {
    display: flex;
    gap: 1rem;
    margin-top: 1rem;
}

.input-row {
    flex: 1;
}

.preview-panel {
    position: sticky;
    top: 2rem;
}

.canvas-container {
    background: white;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    overflow: hidden;
    min-height: 400px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--border-color);
    position: relative;
}

canvas {
    max-width: 100%;
    max-height: 80vh;
    display: block;
}

.placeholder-msg {
    color: var(--text-secondary);
    text-align: center;
}

.hidden {
    display: none;
}

@media (max-width: 900px) {
    .app-grid {
        grid-template-columns: 1fr;
    }
    .preview-panel {
        position: static;
        order: -1;
    }
}