:root {
    color-scheme: light;
    --page-bg: #f5f7fb;
    --panel-bg: rgba(255, 255, 255, 0.86);
    --panel-border: rgba(15, 23, 42, 0.1);
    --text-primary: #0f172a;
    --text-secondary: #526173;
    --muted-bg: #eef2f7;
    --input-bg: #ffffff;
    --input-border: rgba(15, 23, 42, 0.16);
    --accent: #4f46e5;
    --accent-strong: #3730a3;
    --accent-soft: rgba(79, 70, 229, 0.1);
    --green: #059669;
    --green-soft: rgba(5, 150, 105, 0.12);
    --red: #dc2626;
    --red-soft: rgba(220, 38, 38, 0.11);
    --amber: #b45309;
    --amber-soft: rgba(245, 158, 11, 0.14);
    --shadow: 0 22px 60px rgba(15, 23, 42, 0.08);
}

html.dark,
body.dark-mode {
    color-scheme: dark;
    --page-bg: #0b1020;
    --panel-bg: rgba(15, 23, 42, 0.82);
    --panel-border: rgba(148, 163, 184, 0.18);
    --text-primary: #f8fafc;
    --text-secondary: #a8b3c5;
    --muted-bg: rgba(148, 163, 184, 0.1);
    --input-bg: rgba(2, 6, 23, 0.52);
    --input-border: rgba(148, 163, 184, 0.24);
    --accent: #818cf8;
    --accent-strong: #a5b4fc;
    --accent-soft: rgba(129, 140, 248, 0.14);
    --green: #34d399;
    --green-soft: rgba(52, 211, 153, 0.14);
    --red: #f87171;
    --red-soft: rgba(248, 113, 113, 0.13);
    --amber: #fbbf24;
    --amber-soft: rgba(251, 191, 36, 0.15);
    --shadow: 0 24px 70px rgba(0, 0, 0, 0.34);
}

* {
    box-sizing: border-box;
}

body {
    min-height: 100vh;
    margin: 0;
    background:
        linear-gradient(rgba(15, 23, 42, 0.035) 1px, transparent 1px),
        linear-gradient(90deg, rgba(15, 23, 42, 0.035) 1px, transparent 1px),
        var(--page-bg);
    background-size: 36px 36px;
    color: var(--text-primary);
    font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

button,
select,
textarea {
    font: inherit;
}

button {
    cursor: pointer;
}

textarea {
    resize: vertical;
}

.page-shell {
    width: min(1180px, calc(100vw - 32px));
    margin: 0 auto;
    padding: 28px 0 40px;
}

.top-bar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 18px;
    margin-bottom: 24px;
}

.brand {
    display: flex;
    align-items: center;
    gap: 12px;
    min-width: 0;
}

.brand-mark {
    display: grid;
    width: 38px;
    height: 38px;
    place-items: center;
    border: 1px solid var(--panel-border);
    border-radius: 8px;
    background: var(--panel-bg);
    color: var(--accent);
    box-shadow: var(--shadow);
}

.brand-title {
    margin: 0;
    font-size: clamp(1.25rem, 4vw, 2rem);
    line-height: 1.1;
    letter-spacing: 0;
}

.brand-subtitle {
    margin: 5px 0 0;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.top-actions {
    display: flex;
    align-items: center;
    gap: 10px;
    flex-wrap: wrap;
    justify-content: flex-end;
}

.icon-link,
.icon-button,
.primary-button,
.secondary-button,
.segment-button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 40px;
    border: 1px solid var(--panel-border);
    border-radius: 8px;
    background: var(--panel-bg);
    color: var(--text-primary);
    text-decoration: none;
    transition: border-color 0.18s ease, background-color 0.18s ease, color 0.18s ease, transform 0.18s ease;
}

.icon-link,
.icon-button {
    min-width: 40px;
    padding: 0 12px;
}

.icon-link:hover,
.icon-button:hover,
.secondary-button:hover,
.segment-button:hover {
    border-color: var(--accent);
    color: var(--accent-strong);
}

.primary-button {
    border-color: var(--accent);
    background: var(--accent);
    color: #ffffff;
    padding: 0 18px;
    font-weight: 700;
}

.primary-button:hover {
    background: var(--accent-strong);
    border-color: var(--accent-strong);
}

.secondary-button {
    padding: 0 14px;
    font-weight: 650;
}

.tool-panel {
    border: 1px solid var(--panel-border);
    border-radius: 8px;
    background: var(--panel-bg);
    box-shadow: var(--shadow);
    backdrop-filter: blur(14px);
}

.panel-section {
    padding: 18px;
}

.panel-section + .panel-section {
    border-top: 1px solid var(--panel-border);
}

.toolbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 14px;
    flex-wrap: wrap;
}

.control-group {
    display: flex;
    align-items: center;
    gap: 10px;
    flex-wrap: wrap;
}

.field-label {
    display: flex;
    flex-direction: column;
    gap: 6px;
    color: var(--text-secondary);
    font-size: 0.78rem;
    font-weight: 700;
}

.select-field {
    min-height: 40px;
    min-width: 150px;
    border: 1px solid var(--input-border);
    border-radius: 8px;
    background: var(--input-bg);
    color: var(--text-primary);
    padding: 0 12px;
}

.toggle-label {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    min-height: 40px;
    border: 1px solid var(--input-border);
    border-radius: 8px;
    background: var(--input-bg);
    color: var(--text-secondary);
    padding: 0 12px;
    font-size: 0.84rem;
    font-weight: 700;
    user-select: none;
}

.toggle-label input {
    accent-color: var(--accent);
}

.textarea-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
}

.text-field {
    display: flex;
    flex-direction: column;
    gap: 8px;
    min-width: 0;
}

.text-field-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 10px;
    color: var(--text-secondary);
    font-size: 0.82rem;
    font-weight: 800;
}

.text-count {
    font-size: 0.76rem;
    font-weight: 700;
}

.text-area {
    width: 100%;
    min-height: 310px;
    border: 1px solid var(--input-border);
    border-radius: 8px;
    background: var(--input-bg);
    color: var(--text-primary);
    padding: 14px;
    line-height: 1.55;
    font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
    font-size: 0.9rem;
    outline: none;
}

.text-area:focus {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-soft);
}

.segment-control {
    display: inline-flex;
    border: 1px solid var(--input-border);
    border-radius: 8px;
    overflow: hidden;
    background: var(--input-bg);
}

.segment-button {
    min-height: 38px;
    border: 0;
    border-radius: 0;
    background: transparent;
    padding: 0 14px;
    color: var(--text-secondary);
    font-weight: 800;
}

.segment-button.active {
    background: var(--accent);
    color: #ffffff;
}

.output-layout {
    display: grid;
    grid-template-columns: 1fr;
    gap: 16px;
}

.stats-row {
    display: flex;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
}

.stat-pill {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    min-height: 30px;
    border-radius: 999px;
    background: var(--muted-bg);
    color: var(--text-secondary);
    padding: 0 10px;
    font-size: 0.78rem;
    font-weight: 800;
}

.stat-pill.add {
    background: var(--green-soft);
    color: var(--green);
}

.stat-pill.remove {
    background: var(--red-soft);
    color: var(--red);
}

.stat-pill.change {
    background: var(--amber-soft);
    color: var(--amber);
}

.result-box {
    max-height: min(70vh, 620px);
    border: 1px solid var(--panel-border);
    border-radius: 8px;
    overflow: auto;
    background: var(--input-bg);
}

.diff-viewer {
    display: block;
}

.diff-overview {
    position: fixed;
    top: 18vh;
    right: clamp(14px, 3vw, 52px);
    z-index: 30;
    width: 96px;
    height: min(68vh, 680px);
    min-height: 340px;
    border: 1px solid rgba(79, 70, 229, 0.26);
    border-radius: 8px;
    background:
        linear-gradient(to right, transparent 47%, var(--panel-border) 47%, var(--panel-border) 53%, transparent 53%),
        rgba(255, 255, 255, 0.84);
    box-shadow: 0 24px 70px rgba(15, 23, 42, 0.18);
    backdrop-filter: blur(18px);
    -webkit-backdrop-filter: blur(18px);
    overflow: hidden;
    opacity: 0;
    pointer-events: none;
    transform: translateX(10px);
    transition: opacity 0.18s ease, transform 0.18s ease;
}

.dark-mode .diff-overview {
    background:
        linear-gradient(to right, transparent 47%, var(--panel-border) 47%, var(--panel-border) 53%, transparent 53%),
        rgba(15, 23, 42, 0.84);
    box-shadow: 0 24px 70px rgba(0, 0, 0, 0.42);
}

.diff-overview.active {
    opacity: 1;
    pointer-events: auto;
    transform: translateX(0);
}

.diff-overview-track {
    position: relative;
    height: 100%;
    margin: 10px 18px;
}

.diff-overview-thumb {
    position: absolute;
    left: -9px;
    right: -9px;
    min-height: 34px;
    border: 2px solid var(--accent);
    border-radius: 8px;
    background: rgba(79, 70, 229, 0.08);
    cursor: grab;
    z-index: 2;
}

.diff-overview-thumb:active {
    cursor: grabbing;
}

.diff-overview-thumb:focus-visible {
    outline: 2px solid var(--accent-strong);
    outline-offset: 2px;
}

.diff-overview-empty {
    display: grid;
    height: 100%;
    place-items: center;
    color: var(--text-secondary);
    font-size: 0.68rem;
    font-weight: 800;
    writing-mode: vertical-rl;
    letter-spacing: 0;
}

.diff-overview-marker {
    position: absolute;
    left: 0;
    width: 100%;
    min-height: 4px;
    border: 0;
    border-radius: 4px;
    padding: 0;
    opacity: 0.88;
}

.diff-overview-marker:hover,
.diff-overview-marker:focus-visible {
    opacity: 1;
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

.diff-overview-marker.add {
    background: var(--green);
}

.diff-overview-marker.remove {
    background: var(--red);
}

.diff-overview-marker.change {
    background: var(--amber);
}

.diff-table {
    width: 100%;
    border-collapse: collapse;
    table-layout: fixed;
    font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
    font-size: 0.84rem;
}

.diff-table th,
.diff-table td {
    border-bottom: 1px solid var(--panel-border);
    padding: 9px 10px;
    vertical-align: top;
}

.diff-table th {
    position: sticky;
    top: 0;
    z-index: 1;
    background: var(--muted-bg);
    color: var(--text-secondary);
    text-align: left;
    font-family: inherit;
    font-size: 0.76rem;
}

.line-number {
    width: 64px;
    color: var(--text-secondary);
    text-align: right;
    user-select: none;
}

.diff-cell {
    white-space: pre-wrap;
    overflow-wrap: anywhere;
}

.diff-row.add .right-cell,
.diff-row.change .right-cell {
    background: var(--green-soft);
}

.diff-row.remove .left-cell,
.diff-row.change .left-cell {
    background: var(--red-soft);
}

.diff-row.change .left-cell,
.diff-row.change .right-cell {
    background: var(--amber-soft);
}

.diff-row.focused td {
    animation: diffFocus 1.4s ease;
}

@keyframes diffFocus {
    0% {
        box-shadow: inset 0 0 0 999px var(--accent-soft);
    }

    100% {
        box-shadow: inset 0 0 0 999px transparent;
    }
}

.diff-mark {
    border-radius: 4px;
    padding: 1px 2px;
}

.diff-mark.remove {
    background: rgba(220, 38, 38, 0.22);
}

.diff-mark.add {
    background: rgba(5, 150, 105, 0.22);
}

.empty-state {
    padding: 28px;
    color: var(--text-secondary);
    text-align: center;
    font-size: 0.9rem;
    font-weight: 700;
}

.message {
    min-height: 22px;
    color: var(--text-secondary);
    font-size: 0.84rem;
    font-weight: 700;
}

.message.error {
    color: var(--red);
}

.message.success {
    color: var(--green);
}

@media (max-width: 820px) {
    .page-shell {
        width: min(100vw - 20px, 1180px);
        padding-top: 18px;
    }

    .top-bar {
        align-items: flex-start;
    }

    .textarea-grid {
        grid-template-columns: 1fr;
    }

    .text-area {
        min-height: 240px;
    }

    .toolbar {
        align-items: stretch;
    }

    .control-group,
    .top-actions {
        width: 100%;
    }

    .primary-button,
    .secondary-button,
    .segment-control,
    .field-label,
    .select-field {
        flex: 1;
    }

    .segment-button {
        flex: 1;
    }

    .diff-table {
        min-width: 720px;
    }

    .diff-overview {
        top: auto;
        right: 10px;
        bottom: 10px;
        left: 10px;
        width: auto;
        height: 72px;
        min-height: 44px;
        background:
            linear-gradient(to bottom, transparent 47%, var(--panel-border) 47%, var(--panel-border) 53%, transparent 53%),
            rgba(255, 255, 255, 0.88);
    }

    .dark-mode .diff-overview {
        background:
            linear-gradient(to bottom, transparent 47%, var(--panel-border) 47%, var(--panel-border) 53%, transparent 53%),
            rgba(15, 23, 42, 0.88);
    }

    .diff-overview-track {
        height: auto;
        margin: 17px 18px;
    }

    .diff-overview-empty {
        writing-mode: horizontal-tb;
    }

    .diff-overview-thumb {
        top: -7px !important;
        left: var(--thumb-left, 0);
        right: auto;
        width: max(var(--thumb-width, 12%), 36px);
        height: 36px !important;
        min-height: 36px;
    }

    .diff-overview-marker {
        top: 10px !important;
        left: var(--marker-left, 0);
        width: max(var(--marker-width, 4px), 4px);
        height: 22px !important;
    }
}