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

:root {
    --dos-black: #000000;
    --dos-blue: #0000AA;
    --dos-green: #00AA00;
    --dos-cyan: #00AAAA;
    --dos-red: #AA0000;
    --dos-magenta: #AA00AA;
    --dos-brown: #AA5500;
    --dos-lightgray: #AAAAAA;
    --dos-darkgray: #555555;
    --dos-lightblue: #5555FF;
    --dos-lightgreen: #55FF55;
    --dos-lightcyan: #55FFFF;
    --dos-lightred: #FF5555;
    --dos-lightmagenta: #FF55FF;
    --dos-yellow: #FFFF55;
    --dos-white: #FFFFFF;
    --phosphor: #33FF33;
}

body {
    background: var(--dos-black);
    color: var(--dos-lightgray);
    font-family: 'VT323', monospace;
    font-size: 18px;
    line-height: 1.4;
    min-height: 100vh;
    overflow-x: hidden;
}

#scanlines {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 9999;
    background: repeating-linear-gradient(
        0deg,
        rgba(0, 0, 0, 0.15) 0px,
        rgba(0, 0, 0, 0.15) 1px,
        transparent 1px,
        transparent 3px
    );
}

#root {
    max-width: 960px;
    margin: 0 auto;
    padding: 8px 16px;
    position: relative;
}

.dos-box {
    border: 2px solid var(--dos-lightgray);
    margin: 8px 0;
    position: relative;
}

.dos-box-double {
    border: 3px double var(--dos-lightcyan);
    padding: 16px;
    margin: 8px 0;
}

.header-bar {
    background: var(--dos-blue);
    color: var(--dos-white);
    padding: 12px 16px;
    text-align: center;
}

.header-bar h1 {
    font-size: 36px;
    letter-spacing: 4px;
    text-shadow: 2px 2px 0 var(--dos-black);
    margin-bottom: 4px;
}

.header-bar .subtitle {
    color: var(--dos-lightcyan);
    font-size: 20px;
}

.drop-zone {
    border: 3px dashed var(--dos-lightcyan);
    padding: 40px 20px;
    text-align: center;
    cursor: pointer;
    transition: background 0.2s;
    margin: 8px 0;
    background: rgba(0, 0, 170, 0.1);
}

.drop-zone:hover,
.drop-zone.dragover {
    background: rgba(0, 170, 170, 0.15);
    border-color: var(--dos-yellow);
}

.drop-zone .big-text {
    font-size: 28px;
    color: var(--dos-lightcyan);
    margin-bottom: 8px;
}

.drop-zone .small-text {
    font-size: 16px;
    color: var(--dos-darkgray);
}

.status-line {
    background: var(--dos-blue);
    color: var(--dos-yellow);
    padding: 4px 12px;
    font-size: 16px;
}

.transport-bar {
    display: flex;
    gap: 8px;
    padding: 12px;
    background: rgba(0, 0, 170, 0.2);
    border: 2px solid var(--dos-darkgray);
    margin: 8px 0;
    flex-wrap: wrap;
    align-items: center;
}

.dos-btn {
    background: var(--dos-darkgray);
    color: var(--dos-white);
    border: 2px solid var(--dos-lightgray);
    padding: 6px 16px;
    font-family: 'VT323', monospace;
    font-size: 18px;
    cursor: pointer;
    transition: all 0.1s;
    white-space: nowrap;
}

.dos-btn:hover {
    background: var(--dos-lightgray);
    color: var(--dos-black);
}

.dos-btn.active {
    background: var(--dos-lightcyan);
    color: var(--dos-black);
}

.dos-btn:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

.controls-row {
    display: flex;
    gap: 12px;
    align-items: center;
    flex-wrap: wrap;
    padding: 8px 12px;
    margin: 4px 0;
}

.control-group {
    display: flex;
    align-items: center;
    gap: 6px;
}

.control-group label {
    color: var(--dos-lightgray);
    font-size: 16px;
}

.dos-slider {
    -webkit-appearance: none;
    appearance: none;
    height: 8px;
    background: var(--dos-darkgray);
    border: 1px solid var(--dos-lightgray);
    outline: none;
}

.dos-slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 14px;
    height: 20px;
    background: var(--dos-lightcyan);
    cursor: pointer;
    border: 1px solid var(--dos-white);
}

.dos-slider::-moz-range-thumb {
    width: 14px;
    height: 20px;
    background: var(--dos-lightcyan);
    cursor: pointer;
    border: 1px solid var(--dos-white);
}

.dos-input {
    background: var(--dos-black);
    color: var(--dos-lightgreen);
    border: 1px solid var(--dos-darkgray);
    font-family: 'VT323', monospace;
    font-size: 16px;
    padding: 2px 6px;
    width: 80px;
}

canvas#oscilloscope {
    display: block;
    width: 100%;
    height: 180px;
    border: 2px solid var(--dos-darkgray);
    background: var(--dos-black);
}

.progress-container {
    position: relative;
    height: 24px;
    background: var(--dos-black);
    border: 2px solid var(--dos-darkgray);
    margin: 4px 0;
    cursor: pointer;
}

.progress-fill {
    height: 100%;
    background: var(--dos-green);
    transition: width 0.05s linear;
}

.progress-loop-region {
    position: absolute;
    top: 0;
    height: 100%;
    background: rgba(0, 170, 170, 0.3);
    border-left: 1px solid var(--dos-lightcyan);
    border-right: 1px solid var(--dos-lightcyan);
    pointer-events: none;
}

.data-panel {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 4px 16px;
    padding: 8px 12px;
    background: rgba(0, 0, 0, 0.5);
    border: 1px solid var(--dos-darkgray);
    margin: 4px 0;
}

.data-item {
    display: flex;
    justify-content: space-between;
    font-size: 16px;
}

.data-label {
    color: var(--dos-darkgray);
}

.data-value {
    color: var(--dos-lightgreen);
}

.hex-view {
    max-height: 200px;
    overflow-y: auto;
    background: var(--dos-black);
    border: 1px solid var(--dos-darkgray);
    padding: 8px;
    font-size: 14px;
    line-height: 1.6;
    margin: 4px 0;
}

.hex-line {
    white-space: pre;
    color: var(--dos-lightgray);
}

.hex-line .offset {
    color: var(--dos-lightcyan);
}

.hex-line .highlight {
    background: var(--dos-yellow);
    color: var(--dos-black);
}

.collapsible-header {
    background: var(--dos-blue);
    color: var(--dos-lightcyan);
    padding: 4px 12px;
    cursor: pointer;
    border: 1px solid var(--dos-darkgray);
    font-size: 16px;
    user-select: none;
}

.collapsible-header:hover {
    background: var(--dos-lightblue);
}

.about-panel {
    padding: 12px;
    border: 1px solid var(--dos-darkgray);
    margin: 4px 0;
    color: var(--dos-lightgray);
    font-size: 16px;
    line-height: 1.6;
}

.about-panel .tribute {
    color: var(--dos-yellow);
    margin-top: 8px;
}

.footer-bar {
    background: var(--dos-lightgray);
    color: var(--dos-black);
    padding: 4px 12px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 8px;
    font-size: 16px;
}

.footer-bar a {
    color: var(--dos-blue);
    text-decoration: none;
}

.footer-bar a:hover {
    color: var(--dos-red);
    text-decoration: underline;
}

.preset-bar {
    display: flex;
    gap: 8px;
    padding: 8px 12px;
    flex-wrap: wrap;
    align-items: center;
}

.preset-bar span {
    color: var(--dos-darkgray);
    font-size: 16px;
}

.volume-control {
    display: flex;
    align-items: center;
    gap: 6px;
}

.section-title {
    color: var(--dos-lightcyan);
    font-size: 18px;
    padding: 4px 0;
    border-bottom: 1px solid var(--dos-darkgray);
    margin-bottom: 4px;
}

.keyboard-help {
    font-size: 14px;
    color: var(--dos-darkgray);
    padding: 4px 12px;
}

.keyboard-help span {
    color: var(--dos-lightcyan);
}

@media (max-width: 640px) {
    #root {
        padding: 4px 8px;
    }
    .header-bar h1 {
        font-size: 24px;
        letter-spacing: 2px;
    }
    .data-panel {
        grid-template-columns: 1fr;
    }
    .transport-bar {
        justify-content: center;
    }
}