:root {
    --bg: #f4f5f7;
    --card: #ffffff;
    --border: #d8dce2;
    --accent: #3a7afe;
    --accent-hover: #2f63d6;
    --text: #1c2330;
    --muted: #6b7280;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg);
    color: var(--text);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    padding: 24px;
}

.card {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 32px;
    width: 100%;
    max-width: 520px;
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.06);
}

h1 {
    margin: 0;
    font-size: 28px;
}

.tagline {
    margin: 4px 0 24px;
    color: var(--muted);
    font-size: 14px;
}

.dropzone {
    border: 2px dashed var(--border);
    border-radius: 10px;
    padding: 28px 16px;
    text-align: center;
    transition: border-color 0.15s, background 0.15s;
}

.dropzone.dragover {
    border-color: var(--accent);
    background: rgba(58, 122, 254, 0.05);
}

.link {
    color: var(--accent);
    cursor: pointer;
    text-decoration: underline;
}

.file-list {
    list-style: none;
    margin: 16px 0 0;
    padding: 0;
    text-align: left;
    font-size: 13px;
    color: var(--muted);
    max-height: 120px;
    overflow-y: auto;
}

.file-list li {
    padding: 2px 0;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.controls {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
    margin: 24px 0;
}

.field {
    display: flex;
    flex-direction: column;
    gap: 6px;
    font-size: 13px;
}

.field:first-child {
    grid-column: 1 / -1;
}

.field span {
    color: var(--muted);
}

select,
input[type="number"] {
    padding: 8px 10px;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 14px;
    background: #fff;
    color: var(--text);
}

.convert {
    width: 100%;
    padding: 12px;
    border: none;
    border-radius: 8px;
    background: var(--accent);
    color: #fff;
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.15s;
}

.convert:hover:not(:disabled) {
    background: var(--accent-hover);
}

.convert:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.status {
    margin: 16px 0 0;
    font-size: 13px;
    color: var(--muted);
    min-height: 18px;
    text-align: center;
}

.status.error {
    color: #d23b3b;
}