:root {
    --color-bg: #0D0B1E;
    --color-surface: rgba(108, 92, 231, 0.05);
    --color-surface-solid: #151230;
    --color-glass: rgba(162, 155, 254, 0.04);
    --color-border: rgba(108, 92, 231, 0.18);
    --color-border-focus: #6C5CE7;
    --color-text: #E4E0F8;
    --color-text-secondary: #9B93C8;
    --color-text-muted: #5C5680;
    --color-primary: #6C5CE7;
    --color-primary-hover: #5A4BD6;
    --color-primary-glow: rgba(108, 92, 231, 0.25);
    --color-secondary: #A29BFE;
    --color-accent: #FD79A8;
    --color-added-bg: rgba(0, 206, 201, 0.12);
    --color-added-text: #00CEC9;
    --color-removed-bg: rgba(253, 121, 168, 0.12);
    --color-removed-text: #FD79A8;
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: 'JetBrains Mono', monospace;
    --radius: 12px;
    --radius-sm: 8px;
    --transition: 200ms cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
    font-size: 15px;
    -webkit-font-smoothing: antialiased;
}

body {
    font-family: var(--font-sans);
    background: var(--color-bg);
    color: var(--color-text);
    min-height: 100vh;
}

.app-header {
    background: var(--color-surface-solid);
    border-bottom: 1px solid var(--color-border);
}

.header-inner {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    height: 56px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    color: var(--color-primary);
}

.logo h1 {
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--color-text);
}

.header-actions {
    display: flex;
    gap: 6px;
}

.app-main {
    max-width: 1200px;
    margin: 0 auto;
    padding: 24px;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 9px 18px;
    border-radius: var(--radius-sm);
    font-family: var(--font-sans);
    font-size: 0.87rem;
    font-weight: 600;
    border: none;
    cursor: pointer;
    transition: all var(--transition);
}

.btn-primary {
    background: var(--color-primary);
    color: #fff;
}

.btn-primary:hover {
    background: var(--color-primary-hover);
    box-shadow: 0 4px 16px var(--color-primary-glow);
}

.btn-ghost {
    background: transparent;
    color: var(--color-text-secondary);
}

.btn-ghost:hover {
    color: var(--color-text);
}

.btn-sm {
    padding: 5px 10px;
    font-size: 0.78rem;
}

/* Input */
.input-section {
    background: var(--color-surface-solid);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: 20px;
}

.input-pair {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

.input-col label {
    display: block;
    font-size: 0.72rem;
    font-weight: 700;
    color: var(--color-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 6px;
}

.input-col textarea {
    width: 100%;
    padding: 12px 14px;
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    font-family: var(--font-mono);
    font-size: 0.85rem;
    color: var(--color-text);
    resize: vertical;
    line-height: 1.6;
    transition: border-color var(--transition);
}

.input-col textarea:focus {
    outline: none;
    border-color: var(--color-border-focus);
    box-shadow: 0 0 0 3px rgba(108, 92, 231, 0.1);
}

.input-actions {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-top: 14px;
}

.view-toggle {
    display: flex;
    gap: 4px;
    margin-left: auto;
    background: var(--color-bg);
    border-radius: var(--radius-sm);
    padding: 3px;
}

.view-btn {
    padding: 5px 14px;
    border: none;
    border-radius: 6px;
    font-family: var(--font-sans);
    font-size: 0.78rem;
    font-weight: 600;
    color: var(--color-text-muted);
    background: transparent;
    cursor: pointer;
    transition: all var(--transition);
}

.view-btn.active {
    background: var(--color-primary);
    color: #fff;
}

/* Stats */
.diff-stats {
    display: flex;
    align-items: center;
    gap: 16px;
    font-size: 0.82rem;
    font-weight: 600;
}

.stat-added {
    color: var(--color-added-text);
}

.stat-removed {
    color: var(--color-removed-text);
}

.stat-unchanged {
    color: var(--color-text-muted);
}

/* Diff Output */
.diff-output {
    background: var(--color-surface-solid);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    overflow: hidden;
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(6px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Side-by-side */
.diff-side {
    display: grid;
    grid-template-columns: 1fr 1fr;
}

.diff-side .diff-pane {
    overflow-x: auto;
}

.diff-line {
    display: flex;
    font-family: var(--font-mono);
    font-size: 0.8rem;
    line-height: 1.6;
    min-height: 1.6em;
}

.diff-line .line-num {
    width: 40px;
    min-width: 40px;
    text-align: right;
    padding: 0 8px;
    color: var(--color-text-muted);
    user-select: none;
    flex-shrink: 0;
}

.diff-line .line-content {
    flex: 1;
    padding: 0 12px;
    white-space: pre-wrap;
    word-break: break-all;
}

.diff-line.added {
    background: var(--color-added-bg);
}

.diff-line.added .line-content {
    color: var(--color-added-text);
}

.diff-line.removed {
    background: var(--color-removed-bg);
}

.diff-line.removed .line-content {
    color: var(--color-removed-text);
}

.diff-line.unchanged .line-content {
    color: var(--color-text-secondary);
}

/* Inline */
.diff-inline {
    overflow-x: auto;
}

/* Separator */
.diff-pane-divider {
    width: 1px;
    background: var(--color-border);
}

.toast {
    position: fixed;
    bottom: 24px;
    left: 50%;
    transform: translateX(-50%);
    padding: 10px 24px;
    background: var(--color-primary);
    color: #fff;
    border-radius: var(--radius-sm);
    font-size: 0.87rem;
    font-weight: 600;
    box-shadow: 0 4px 24px var(--color-primary-glow);
    z-index: 200;
    animation: toastSlide 0.3s ease;
}

@keyframes toastSlide {
    from {
        opacity: 0;
        transform: translateX(-50%) translateY(8px);
    }

    to {
        opacity: 1;
        transform: translateX(-50%) translateY(0);
    }
}

@media (max-width: 700px) {
    .input-pair {
        grid-template-columns: 1fr;
    }

    .diff-side {
        grid-template-columns: 1fr;
    }

    .app-main {
        padding: 16px;
    }
}