:root {
    --primary-color: #007bff;
    --background-color: #f8f9fa;
    --text-color: #212529;
    --border-color: #dee2e6;
    --drop-zone-bg: #fff;
}

body {
    font-family: sans-serif;
    background-color: var(--background-color);
    color: var(--text-color);
    margin: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    min-height: 100vh;
}

body.dark-mode {
    --primary-color: #4da3ff;
    --background-color: #121212;
    --text-color: #e0e0e0;
    --border-color: #444;
    --drop-zone-bg: #1e1e1e;
}

header {
    width: 100%;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--border-color);
    box-sizing: border-box;
}

header h1 {
    margin: 0;
    font-size: 1.5rem;
}

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

.lang-selector {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.lang-icon {
    font-size: 1.3rem;
    display: flex;
    align-items: center;
}

main {
    flex-grow: 1;
    padding: 2rem;
    width: 100%;
    max-width: 800px;
    box-sizing: border-box;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1.5rem;
}

.security-notice {
    width: 100%;
    padding: 1.5rem;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 12px;
    color: white;
    text-align: center;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

body.dark-mode .security-notice {
    background: linear-gradient(135deg, #4a5568 0%, #2d3748 100%);
}

.security-icon {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
}

.security-notice h2 {
    margin: 0 0 1rem 0;
    font-size: 1.5rem;
    font-weight: 600;
}

.security-features {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    align-items: flex-start;
    max-width: 600px;
    margin: 0 auto;
}

.security-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    text-align: left;
    font-size: 0.95rem;
}

.check-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 24px;
    height: 24px;
    background-color: rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    font-weight: bold;
    flex-shrink: 0;
}

#drop-zone {
    width: 100%;
    padding: 3rem;
    border: 2px dashed var(--border-color);
    border-radius: 8px;
    text-align: center;
    background-color: var(--drop-zone-bg);
    cursor: pointer;
}

#drop-zone.drag-over {
    border-color: var(--primary-color);
    background-color: #e9ecef;
}

body.dark-mode #drop-zone.drag-over {
     background-color: #2a2a2a;
}


#file-input {
    display: none;
}

.file-label {
    display: inline-block;
    padding: 0.5rem 1rem;
    background-color: var(--primary-color);
    color: white;
    border-radius: 5px;
    cursor: pointer;
}


#file-list {
    width: 100%;
}

.file-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.5rem;
    border: 1px solid var(--border-color);
    border-radius: 5px;
    margin-bottom: 0.5rem;
    background-color: var(--drop-zone-bg);
}

.remove-btn {
    background: transparent;
    border: none;
    font-size: 1.2rem;
    cursor: pointer;
    color: var(--text-color);
}

.remove-btn:hover {
    opacity: 0.7;
}

.control-panel {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
    width: 100%;
}

.date-time-inputs {
    display: flex;
    justify-content: center;
    width: 100%;
}

.date-time-inputs input {
    width: 100%;
    max-width: 350px;
    padding: 0.75rem;
    font-size: 1rem;
    border: 1px solid var(--border-color);
    border-radius: 5px;
    background-color: var(--drop-zone-bg);
    color: var(--text-color);
    text-align: center;
    cursor: pointer;
}

.format-selection {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
    margin-top: 1rem;
    padding: 1rem;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background-color: var(--drop-zone-bg);
    width: 100%;
    box-sizing: border-box;
}

.format-selection h3 {
    margin: 0;
    font-size: 1rem;
    color: var(--text-color);
}

.format-selection select {
    padding: 0.5rem;
    border: 1px solid var(--border-color);
    border-radius: 5px;
    background-color: var(--drop-zone-bg);
    color: var(--text-color);
    font-size: 0.95rem;
    cursor: pointer;
    min-width: 250px;
}

.format-note {
    margin: 0;
    font-size: 0.85rem;
    color: #6c757d;
    text-align: center;
}

.info-box {
    display: flex;
    gap: 1rem;
    padding: 1rem;
    background: linear-gradient(135deg, #e3f2fd 0%, #bbdefb 100%);
    border-radius: 8px;
    border-left: 4px solid #2196f3;
    margin-top: 1rem;
    width: 100%;
    box-sizing: border-box;
}

body.dark-mode .info-box {
    background: linear-gradient(135deg, #1e3a5f 0%, #2c5282 100%);
    border-left-color: #4da3ff;
}

.info-icon {
    font-size: 1.5rem;
    flex-shrink: 0;
}

.info-content {
    flex: 1;
    text-align: left;
}

.info-content h4 {
    margin: 0 0 0.5rem 0;
    font-size: 1rem;
    color: #1976d2;
}

body.dark-mode .info-content h4 {
    color: #64b5f6;
}

.info-content p {
    margin: 0 0 0.75rem 0;
    font-size: 0.9rem;
    line-height: 1.5;
    color: var(--text-color);
}

.os-compatibility {
    display: flex;
    gap: 0.5rem;
    align-items: center;
    font-size: 0.85rem;
    color: var(--text-color);
}

.compatible {
    color: #4caf50;
    font-weight: 500;
}

body.dark-mode .compatible {
    color: #81c784;
}

#change-download-btn {
    padding: 0.75rem 1.5rem;
    font-size: 1.1rem;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.2s;
}

#change-download-btn:hover {
    opacity: 0.9;
}

footer {
    width: 100%;
    text-align: center;
    padding: 1rem;
    border-top: 1px solid var(--border-color);
    font-size: 0.9rem;
    color: #6c757d;
}

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

@media (max-width: 768px) {
    header {
        flex-direction: column;
        gap: 1rem;
        padding: 1rem;
    }

    main {
        padding: 1rem;
    }

    .security-notice {
        padding: 1rem;
    }

    .security-notice h2 {
        font-size: 1.2rem;
    }

    .security-item {
        font-size: 0.85rem;
    }

    .security-icon {
        font-size: 2rem;
    }

    #drop-zone {
        padding: 2rem;
    }

    .date-time-inputs input {
        max-width: 100%;
        font-size: 0.95rem;
    }

    .control-panel h2 {
        font-size: 1.2rem;
        text-align: center;
    }

    footer {
        font-size: 0.8rem;
    }
}