:root {
    --bg-color: #f8f9fa;
    --container-bg: #ffffff;
    --text-color: #212529;
    --primary-color: #4e73df;
    --secondary-color: #858796;
    --border-color: #e3e6f0;
    --success-color: #1cc88a;
    --shadow: 0 0.15rem 1.75rem 0 rgba(58, 59, 69, 0.15);
}

body.dark-mode {
    --bg-color: #1a1c23;
    --container-bg: #242731;
    --text-color: #e1e1e1;
    --primary-color: #6a89e5;
    --border-color: #3a3e4e;
    --shadow: 0 0.15rem 1.75rem 0 rgba(0, 0, 0, 0.5);
}

body {
    font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, system-ui, Roboto, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    margin: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    transition: all 0.3s ease;
}

.container {
    width: 90%;
    max-width: 600px;
    background-color: var(--container-bg);
    padding: 3rem;
    border-radius: 20px;
    box-shadow: var(--shadow);
    text-align: center;
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
    color: var(--primary-color);
}

header p {
    color: var(--secondary-color);
    margin-bottom: 2rem;
}

.drop-zone {
    border: 2px dashed var(--border-color);
    border-radius: 15px;
    padding: 3rem 2rem;
    cursor: pointer;
    transition: all 0.2s ease;
    background-color: rgba(78, 115, 223, 0.02);
}

.drop-zone:hover, .drop-zone.drag-over {
    border-color: var(--primary-color);
    background-color: rgba(78, 115, 223, 0.05);
}

.drop-zone .icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.hidden {
    display: none;
}

.progress-container {
    width: 100%;
    height: 10px;
    background-color: var(--border-color);
    border-radius: 5px;
    margin: 1.5rem 0;
    overflow: hidden;
}

.progress-bar {
    width: 0%;
    height: 100%;
    background-color: var(--primary-color);
    transition: width 0.3s ease;
}

button {
    padding: 0.8rem 1.5rem;
    font-size: 1rem;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    font-weight: 600;
    transition: opacity 0.2s;
}

.primary-button {
    background-color: var(--primary-color);
    color: white;
    width: 100%;
    margin-top: 1rem;
}

.secondary-button {
    background-color: transparent;
    color: var(--secondary-color);
    margin-top: 0.5rem;
}

#theme-toggle {
    position: fixed;
    top: 1.5rem;
    right: 1.5rem;
    background-color: var(--container-bg);
    color: var(--text-color);
    box-shadow: var(--shadow);
}

.success-icon {
    font-size: 4rem;
    color: var(--success-color);
    margin-bottom: 1rem;
}