:root {
    /* Dark Mode (Default) */
    --bg-color: #121212;
    --card-bg: #1e1e1e;
    --text-color: #e0e0e0;
    --heading-color: #ffffff;
    --primary-color: #bb86fc;
    --primary-hover: #9b67e0;
    --success-color: #03dac6;
    --error-color: #cf6679;
    --border-radius: 8px;
    --input-bg: #2c2c2c;
    --input-border: #444;
    --border-color: #333;
    --log-bg: #000000;
    --drop-zone-bg: #252525;
    --drop-zone-border: #444;
}

body.light-mode {
    --bg-color: #f0f2f5;
    --card-bg: #ffffff;
    --text-color: #333;
    --heading-color: #2c3e50;
    --primary-color: #007bff;
    --primary-hover: #0069d9;
    --success-color: #28a745;
    --error-color: #dc3545;
    --input-bg: #ffffff;
    --input-border: #ddd;
    --border-color: #eee;
    --log-bg: #1e1e1e;
    --drop-zone-bg: #f8f9fa;
    --drop-zone-border: #ddd;
}

* {
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    margin: 0;
    padding: 20px;
    display: flex;
    justify-content: center;
    transition: background-color 0.3s, color 0.3s;
    min-height: 100vh;
}

#app {
    width: 100%;
    max-width: 550px;
}

h1 {
    margin: 0;
    color: var(--heading-color);
    font-size: 1.8rem;
}

.header-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

.dark-mode-btn {
    background: var(--input-bg);
    border: 1px solid var(--input-border);
    font-size: 20px;
    padding: 8px 12px;
    cursor: pointer;
    border-radius: var(--border-radius);
    transition: all 0.2s;
}

.dark-mode-btn:hover {
    background: var(--primary-color);
}

.card {
    background: var(--card-bg);
    padding: 20px;
    border-radius: var(--border-radius);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
    margin-bottom: 20px;
    transition: background-color 0.3s;
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--border-color);
    margin-bottom: 15px;
    padding-bottom: 5px;
}

h2 {
    margin: 0;
    font-size: 1.1rem;
    color: var(--heading-color);
}

.cable-note {
    font-size: 13px;
    color: var(--text-color);
    opacity: 0.8;
    margin: 0;
}

/* Drop Zone */
.drop-zone {
    border: 2px dashed var(--drop-zone-border);
    border-radius: var(--border-radius);
    background: var(--drop-zone-bg);
    padding: 40px 20px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s;
}

.drop-zone:hover,
.drop-zone.drag-over {
    border-color: var(--primary-color);
    background: rgba(187, 134, 252, 0.1);
}

.drop-zone-content {
    pointer-events: none;
}

.drop-icon {
    font-size: 48px;
    display: block;
    margin-bottom: 10px;
}

.drop-zone p {
    margin: 5px 0;
    color: var(--text-color);
}

.drop-subtext {
    font-size: 12px;
    opacity: 0.7;
}

/* File Info */
.file-info {
    display: flex;
    align-items: center;
    gap: 15px;
    padding: 12px 15px;
    background: var(--input-bg);
    border-radius: var(--border-radius);
    margin-top: 15px;
}

#file-name {
    flex: 1;
    font-weight: 500;
    color: var(--success-color);
}

#file-size {
    font-size: 12px;
    opacity: 0.7;
}

.btn-small {
    padding: 4px 10px;
    font-size: 12px;
    background: var(--error-color);
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
}

.btn-small:hover {
    opacity: 0.8;
}

/* Buttons */
button {
    background-color: var(--primary-color);
    color: #000;
    border: none;
    padding: 10px 20px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 14px;
    font-weight: 500;
    transition: all 0.2s;
}

button:hover:not(:disabled) {
    background-color: var(--primary-hover);
    opacity: 0.9;
}

button:disabled {
    background-color: #555;
    color: #888;
    cursor: not-allowed;
}

body.light-mode button {
    color: white;
}

body.light-mode button:disabled {
    background-color: #ccc;
    color: #888;
}

.button-row {
    display: flex;
    align-items: center;
    gap: 15px;
    flex-wrap: wrap;
}

.usb-button-group {
    display: flex;
    align-items: stretch;
}

.usb-button-group button {
    border-top-right-radius: 0;
    border-bottom-right-radius: 0;
}

.usb-status-box {
    display: flex;
    align-items: center;
    padding: 0 12px;
    background: var(--input-bg);
    border: 1px solid var(--input-border);
    border-left: none;
    border-top-right-radius: 4px;
    border-bottom-right-radius: 4px;
    font-size: 12px;
}

.status {
    font-weight: bold;
}

.status.connected {
    color: var(--success-color);
}

.status.disconnected {
    color: var(--error-color);
}

/* Log Container */
#log-container {
    background: var(--log-bg);
    color: #00ff00;
    font-family: 'Consolas', 'Monaco', 'Courier New', monospace;
    padding: 12px;
    border-radius: 4px;
    height: 200px;
    overflow-y: auto;
    font-size: 12px;
    line-height: 1.5;
}

.log-entry {
    margin: 2px 0;
}

.log-entry.error {
    color: #ff6b6b;
}

.log-entry.success {
    color: #69db7c;
}

.log-entry.info {
    color: #74c0fc;
}

/* Browser Warning */
.browser-warning {
    background: rgba(207, 102, 121, 0.2);
    border: 1px solid var(--error-color);
    border-radius: var(--border-radius);
    padding: 15px;
    margin-top: 20px;
    display: none;
}

.browser-warning.show {
    display: block;
}