:root {
    color-scheme: light;
    --bg: #ffffff;
    --bg-soft: #f7faff;
    --canvas: #f3f7ff;
    --grid: #dde8fb;
    --text: #0b1d4d;
    --muted: #6a7693;
    --accent: #0d5cff;
    --accent-2: #3d82ff;
    --accent-dark: #0044d1;
    --border: #e2e8f3;
    --border-strong: #c6d0e2;
    --danger: #c0392b;
    --danger-bg: #fdecea;
    --danger-border: #f5c6c2;
    --warning-bg: #fff8e6;
    --warning-border: #f4d58d;
    --success: #16a34a;
    --radius-control: 12px;
    --radius-panel: 18px;
    --shadow-sm: 0 1px 2px rgba(15, 35, 80, .05), 0 1px 3px rgba(15, 35, 80, .04);
    --shadow-panel: 0 2px 4px rgba(15, 35, 80, .03), 0 14px 30px rgba(20, 44, 96, .05);
    --shadow-action: 0 10px 22px rgba(13, 92, 255, .28);
    --shadow-preview: 0 24px 60px rgba(24, 47, 100, .10);
    --focus-ring: 0 0 0 4px rgba(13, 92, 255, .20);
    --transition: 160ms cubic-bezier(.4, 0, .2, 1);
}

* {
    box-sizing: border-box;
}

html {
    min-width: 320px;
    background: var(--bg-soft);
}

body {
    margin: 0;
    color: var(--text);
    background:
        radial-gradient(1200px 600px at 80% -10%, rgba(13, 92, 255, .05), transparent 60%),
        radial-gradient(900px 500px at -10% 0%, rgba(61, 130, 255, .05), transparent 55%),
        var(--bg-soft);
    font-family: "Segoe UI", Arial, sans-serif;
    font-size: 16px;
    line-height: 1.45;
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
}

button,
input,
select,
textarea {
    color: inherit;
    font: inherit;
}

button,
select,
textarea,
input[type="color"],
.upload-zone,
.format-option,
.color-control,
.mode-nav__item,
.preview-stage svg {
    transition: border-color var(--transition), box-shadow var(--transition), background var(--transition), color var(--transition), transform var(--transition), opacity var(--transition);
}

button:focus-visible,
select:focus-visible,
textarea:focus-visible,
input:focus-visible,
a:focus-visible,
.upload-zone:focus-within,
.format-option:focus-within {
    outline: none;
    border-color: var(--accent);
    box-shadow: var(--focus-ring);
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* ───────────────────────── Header ───────────────────────── */

.app-header {
    position: sticky;
    top: 0;
    z-index: 20;
    display: grid;
    grid-template-columns: 360px 1fr auto;
    align-items: stretch;
    min-height: 84px;
    padding: 0 28px;
    border-bottom: 1px solid var(--border);
    background: rgba(255, 255, 255, .82);
    backdrop-filter: saturate(180%) blur(14px);
    -webkit-backdrop-filter: saturate(180%) blur(14px);
}

.brand {
    display: inline-flex;
    align-items: center;
    gap: 13px;
    color: var(--text);
    text-decoration: none;
    font-size: 23px;
    font-weight: 750;
    letter-spacing: -.02em;
}

.brand-mark {
    width: 40px;
    height: 40px;
    padding: 6px;
    border-radius: 11px;
    color: #fff;
    background: linear-gradient(135deg, var(--accent-2), var(--accent));
    box-shadow: 0 6px 16px rgba(13, 92, 255, .30);
}

.mode-nav {
    display: flex;
    align-items: stretch;
    justify-content: center;
    gap: 8px;
}

.mode-nav__item {
    position: relative;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 9px;
    min-width: 132px;
    padding: 0 18px;
    border: 0;
    background: transparent;
    color: var(--muted);
    text-decoration: none;
    font-size: 15px;
    font-weight: 650;
    cursor: pointer;
}

.mode-nav__item svg {
    width: 21px;
    height: 21px;
    opacity: .9;
}

.mode-nav__item::after {
    content: "";
    position: absolute;
    right: 16px;
    bottom: 0;
    left: 16px;
    height: 3px;
    border-radius: 3px 3px 0 0;
    background: linear-gradient(90deg, var(--accent-2), var(--accent));
    transform: scaleX(0);
    transform-origin: center;
    transition: transform var(--transition);
}

.mode-nav__item:hover:not(:disabled) {
    color: var(--text);
}

.mode-nav__item.is-active {
    color: var(--accent);
}

.mode-nav__item.is-active::after {
    transform: scaleX(1);
}

.mode-nav__item:disabled {
    opacity: .5;
    cursor: not-allowed;
}

.menu-button {
    display: none;
    align-self: center;
    width: 44px;
    height: 44px;
    padding: 9px;
    border: 1px solid var(--border);
    border-radius: 11px;
    background: #fff;
    cursor: pointer;
}

.menu-button span {
    display: block;
    height: 2px;
    margin: 5px 0;
    border-radius: 2px;
    background: var(--text);
}

/* ───────────────────────── Shell ───────────────────────── */

.editor-shell {
    display: grid;
    grid-template-columns: minmax(320px, 390px) minmax(420px, 1fr) minmax(250px, 290px);
    gap: 22px;
    width: 100%;
    max-width: 1600px;
    min-height: calc(100vh - 84px);
    margin: 0 auto;
    padding: 26px 22px 32px;
}

.editor-settings {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.panel {
    border: 1px solid var(--border);
    border-radius: var(--radius-panel);
    background: linear-gradient(180deg, #fff, #fdfeff);
    box-shadow: var(--shadow-panel);
}

.content-panel,
.style-panel,
.export-panel {
    padding: 20px;
}

h1,
h2 {
    margin: 0;
    color: var(--text);
    font-size: 18px;
    font-weight: 750;
    letter-spacing: -.015em;
}

.content-panel h1,
.style-panel h2,
.export-panel h2,
.preview-heading h2 {
    display: flex;
    align-items: center;
    gap: 9px;
}

.content-panel h1::before,
.style-panel h2::before,
.export-panel h2::before {
    content: "";
    width: 4px;
    height: 17px;
    border-radius: 3px;
    background: linear-gradient(180deg, var(--accent-2), var(--accent));
}

.textarea-wrap {
    position: relative;
    margin-top: 15px;
}

.textarea-wrap textarea {
    display: block;
    width: 100%;
    min-height: 134px;
    padding: 14px 15px 34px;
    resize: vertical;
    border: 1px solid var(--border-strong);
    border-radius: var(--radius-control);
    background: var(--bg-soft);
    font-size: 15px;
    line-height: 1.5;
}

.textarea-wrap textarea:hover {
    border-color: #aab6cc;
}

.textarea-wrap textarea:focus {
    background: #fff;
}

.textarea-wrap span {
    position: absolute;
    right: 12px;
    bottom: 9px;
    padding: 2px 7px;
    border-radius: 7px;
    background: rgba(255, 255, 255, .85);
    color: var(--muted);
    font-size: 12px;
    font-variant-numeric: tabular-nums;
}

.style-panel h2,
.export-panel h2 {
    margin-bottom: 18px;
}

#qr-form {
    display: grid;
    gap: 14px;
}

.control-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 12px;
}

.field {
    display: grid;
    gap: 7px;
    min-width: 0;
    color: var(--text);
    font-size: 13px;
    font-weight: 650;
}

.field > span:first-child {
    color: var(--muted);
    font-size: 12px;
    font-weight: 650;
    text-transform: uppercase;
    letter-spacing: .03em;
}

.field select,
.color-control {
    width: 100%;
    min-height: 46px;
    border: 1px solid var(--border-strong);
    border-radius: var(--radius-control);
    background: #fff;
}

.field select {
    padding: 0 38px 0 13px;
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 20 20'%3E%3Cpath d='m6 8 4 4 4-4' fill='none' stroke='%230d5cff' stroke-width='1.8' stroke-linecap='round'/%3E%3C/svg%3E");
    background-position: right 12px center;
    background-repeat: no-repeat;
    background-size: 18px;
    font-size: 14px;
    font-weight: 600;
    text-transform: none;
    letter-spacing: 0;
    cursor: pointer;
}

.field select:hover,
.color-control:hover {
    border-color: #9fadc7;
}

.color-control {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 5px 12px 5px 6px;
    text-transform: none;
    letter-spacing: 0;
    cursor: pointer;
}

.color-control input {
    width: 36px;
    height: 34px;
    padding: 0;
    overflow: hidden;
    border: 0;
    border-radius: 8px;
    background: transparent;
    cursor: pointer;
}

.color-control input::-webkit-color-swatch-wrapper {
    padding: 0;
}

.color-control input::-webkit-color-swatch {
    border: 1px solid rgba(11, 29, 77, .12);
    border-radius: 8px;
}

.color-control output {
    min-width: 0;
    overflow: hidden;
    font-size: 13px;
    font-weight: 600;
    font-variant-numeric: tabular-nums;
    text-overflow: ellipsis;
}

/* Icon-tile and segmented controls */
.control {
    display: grid;
    gap: 9px;
    min-width: 0;
}

.control-label {
    color: var(--muted);
    font-size: 12px;
    font-weight: 650;
    text-transform: uppercase;
    letter-spacing: .03em;
}

.tiles {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 9px;
}

.tile {
    position: relative;
    display: grid;
    gap: 7px;
    place-items: center;
    padding: 13px 6px 10px;
    border: 1.5px solid var(--border);
    border-radius: 14px;
    background: #fff;
    cursor: pointer;
    text-align: center;
}

.tile:hover {
    border-color: #aebbd0;
    transform: translateY(-1px);
}

.tile input {
    position: absolute;
    opacity: 0;
    pointer-events: none;
}

.tile-icon {
    display: grid;
    place-items: center;
    width: 36px;
    height: 36px;
    color: #8b99b5;
}

.tile-icon svg {
    width: 34px;
    height: 34px;
}

.tile-text {
    font-size: 11px;
    font-weight: 650;
    color: var(--muted);
}

.tile:has(input:checked) {
    border-color: var(--accent);
    background: linear-gradient(180deg, #f5f9ff, #eaf2ff);
    box-shadow: inset 0 0 0 1px var(--accent);
}

.tile:has(input:checked) .tile-icon,
.tile:has(input:checked) .tile-text {
    color: var(--accent);
}

.tile:has(input:focus-visible) {
    box-shadow: var(--focus-ring);
}

.seg {
    display: grid;
    grid-auto-flow: column;
    grid-auto-columns: 1fr;
    gap: 3px;
    padding: 4px;
    border: 1.5px solid var(--border-strong);
    border-radius: var(--radius-control);
    background: var(--bg-soft);
}

.seg-item {
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 38px;
    padding: 0 4px;
    border-radius: 9px;
    color: var(--muted);
    font-size: 13px;
    font-weight: 650;
    font-variant-numeric: tabular-nums;
    cursor: pointer;
}

.seg-item:hover {
    color: var(--text);
}

.seg-item input {
    position: absolute;
    opacity: 0;
    pointer-events: none;
}

.seg-item:has(input:checked) {
    background: #fff;
    color: var(--accent);
    box-shadow: 0 1px 3px rgba(15, 35, 80, .16);
}

.seg-item:has(input:focus-visible) {
    box-shadow: var(--focus-ring);
}

.upload-field {
    margin-top: 6px;
}

.upload-zone {
    display: grid;
    grid-template-columns: 38px 1fr;
    gap: 4px 12px;
    align-items: center;
    min-height: 118px;
    padding: 16px;
    border: 1.5px dashed #aebbd6;
    border-radius: var(--radius-control);
    background:
        linear-gradient(180deg, #fbfdff, #f4f8ff);
    color: var(--text);
    cursor: pointer;
    font-size: 13px;
    font-weight: 500;
}

.upload-zone:hover,
.upload-zone.is-dragging {
    border-color: var(--accent);
    background: linear-gradient(180deg, #f4f8ff, #eaf2ff);
}

.upload-zone.is-dragging {
    box-shadow: var(--focus-ring);
}

.upload-zone svg {
    grid-row: span 2;
    width: 38px;
    height: 38px;
    padding: 8px;
    border-radius: 10px;
    color: var(--accent);
    background: rgba(13, 92, 255, .08);
}

.upload-zone.is-dragging svg {
    transform: translateY(-2px);
}

.upload-zone strong {
    font-weight: 700;
}

.upload-zone small {
    grid-column: 2;
    color: var(--muted);
    font-size: 11px;
    font-weight: 500;
}

.logo-selection {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 10px;
    margin-top: 8px;
    padding: 10px 10px 10px 14px;
    border: 1px solid var(--border);
    border-radius: var(--radius-control);
    background: var(--canvas);
    font-size: 13px;
    font-weight: 600;
}

.logo-selection[hidden] {
    display: none;
}

.logo-selection span {
    min-width: 0;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.logo-selection button {
    display: grid;
    place-items: center;
    flex: 0 0 30px;
    height: 30px;
    padding: 0;
    border: 0;
    border-radius: 8px;
    background: rgba(192, 57, 43, .10);
    color: var(--danger);
    font-size: 20px;
    line-height: 1;
    cursor: pointer;
}

.logo-selection button:hover {
    background: var(--danger);
    color: #fff;
}

/* ───────────────────────── Preview ───────────────────────── */

.preview-region {
    display: flex;
    min-width: 0;
    flex-direction: column;
}

.preview-heading {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    min-height: 42px;
    padding: 0 4px 12px;
}

.preview-heading span,
.export-note {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    color: var(--muted);
    font-size: 12px;
}

.preview-heading span::before {
    content: "";
    width: 7px;
    height: 7px;
    border-radius: 50%;
    background: var(--success);
    box-shadow: 0 0 0 3px rgba(22, 163, 74, .15);
}

.preview-canvas {
    position: relative;
    display: grid;
    flex: 1;
    place-items: center;
    min-height: 560px;
    padding: clamp(24px, 4vw, 60px);
    overflow: hidden;
    border: 1px solid var(--border);
    border-radius: var(--radius-panel);
    background-color: var(--canvas);
    background-image:
        linear-gradient(var(--grid) 1px, transparent 1px),
        linear-gradient(90deg, var(--grid) 1px, transparent 1px);
    background-size: 26px 26px;
    box-shadow: var(--shadow-preview);
}

.preview-canvas::before {
    content: "";
    position: absolute;
    inset: 0;
    pointer-events: none;
    background: radial-gradient(60% 60% at 50% 42%, rgba(255, 255, 255, .9), rgba(255, 255, 255, 0) 72%);
}

.preview-canvas::after {
    content: "";
    position: absolute;
    inset: 0;
    pointer-events: none;
    border-radius: inherit;
    box-shadow: inset 0 0 0 1px rgba(255, 255, 255, .6);
}

.preview-stage {
    position: relative;
    z-index: 1;
    display: grid;
    place-items: center;
    width: 100%;
}

.preview-stage svg {
    display: block;
    width: min(100%, 620px);
    height: auto;
    max-height: calc(100vh - 230px);
    border-radius: 16px;
    box-shadow: 0 16px 40px rgba(17, 38, 82, .14);
    animation: pop-in 220ms cubic-bezier(.34, 1.4, .5, 1);
}

.preview-canvas.is-loading .preview-stage svg {
    opacity: .35;
    transform: scale(.99);
}

.preview-placeholder {
    position: relative;
    z-index: 1;
    display: none;
    color: #c4d2ea;
}

.preview-placeholder svg {
    width: clamp(120px, 26vw, 190px);
    height: auto;
}

.preview-canvas.is-empty .preview-stage { display: none; }
.preview-canvas.is-empty:not(.is-loading) .preview-placeholder { display: block; }

.preview-loader {
    position: absolute;
    z-index: 2;
    width: 40px;
    height: 40px;
    border: 3px solid rgba(13, 92, 255, .18);
    border-top-color: var(--accent);
    border-radius: 50%;
    opacity: 0;
    pointer-events: none;
    animation: spin .8s linear infinite;
    transition: opacity var(--transition);
}

.preview-canvas.is-loading .preview-loader {
    opacity: 1;
}

.preview-messages {
    min-height: 22px;
    margin-top: 12px;
    padding: 0 4px;
    color: var(--muted);
    font-size: 12.5px;
}

.preview-messages.is-warning {
    padding: 11px 14px;
    border: 1px solid var(--warning-border);
    border-radius: 12px;
    background: var(--warning-bg);
    color: #72510b;
    font-weight: 500;
}

.preview-messages.is-error {
    padding: 11px 14px;
    border: 1px solid var(--danger-border);
    border-radius: 12px;
    background: var(--danger-bg);
    color: var(--danger);
    font-weight: 600;
}

/* ───────────────────────── Export ───────────────────────── */

.export-panel {
    align-self: start;
    position: sticky;
    top: 104px;
}

.format-list {
    display: grid;
    gap: 10px;
}

.format-option {
    position: relative;
    display: grid;
    grid-template-columns: 28px 1fr 22px;
    align-items: center;
    gap: 12px;
    min-height: 60px;
    padding: 10px 14px;
    border: 1.5px solid var(--border);
    border-radius: var(--radius-control);
    background: #fff;
    cursor: pointer;
}

.format-option:hover {
    border-color: #aebbd0;
    transform: translateY(-1px);
    box-shadow: var(--shadow-sm);
}

.format-option input {
    position: absolute;
    opacity: 0;
    pointer-events: none;
}

.format-option:has(input:checked) {
    border-color: var(--accent);
    background: linear-gradient(180deg, #f5f9ff, #eef5ff);
}

.format-glyph {
    width: 26px;
    height: 26px;
    color: var(--muted);
}

.format-option:has(input:checked) .format-glyph {
    color: var(--accent);
}

.format-mark {
    justify-self: end;
    width: 20px;
    height: 20px;
    border: 2px solid var(--border-strong);
    border-radius: 50%;
    background: #fff;
}

.format-option:has(input:checked) .format-mark {
    border-color: var(--accent);
    background: var(--accent);
    box-shadow: inset 0 0 0 3.5px #fff;
}

.format-option strong {
    font-size: 15px;
    font-weight: 700;
    letter-spacing: .015em;
}

.download-button {
    position: relative;
    display: flex;
    width: 100%;
    min-height: 58px;
    align-items: center;
    justify-content: center;
    gap: 10px;
    margin-top: 20px;
    overflow: hidden;
    border: 0;
    border-radius: var(--radius-control);
    background: linear-gradient(135deg, var(--accent-2), var(--accent));
    box-shadow: var(--shadow-action);
    color: #fff;
    font-size: 16px;
    font-weight: 750;
    letter-spacing: .01em;
    cursor: pointer;
}

.download-button::after {
    content: "";
    position: absolute;
    top: 0;
    left: -60%;
    width: 40%;
    height: 100%;
    background: linear-gradient(100deg, transparent, rgba(255, 255, 255, .35), transparent);
    transform: skewX(-18deg);
    transition: left 600ms ease;
}

.download-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 14px 28px rgba(13, 92, 255, .36);
}

.download-button:hover::after {
    left: 130%;
}

.download-button:active {
    transform: translateY(0);
}

.download-button:disabled {
    opacity: .6;
    cursor: wait;
    transform: none;
    box-shadow: var(--shadow-sm);
}

.download-button svg {
    width: 22px;
    height: 22px;
}

.download-button[aria-busy="true"] svg {
    animation: bob .9s ease-in-out infinite;
}

.export-note {
    margin: 14px 0 0;
    justify-content: center;
    text-align: center;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

@keyframes pop-in {
    from { opacity: 0; transform: scale(.96); }
    to { opacity: 1; transform: scale(1); }
}

@keyframes bob {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(3px); }
}

/* ───────────────────────── Responsive ───────────────────────── */

@media (max-width: 1179px) {
    .app-header {
        grid-template-columns: 260px 1fr;
    }

    .mode-nav {
        justify-content: flex-end;
    }

    .editor-shell {
        grid-template-columns: minmax(300px, 360px) minmax(360px, 1fr);
    }

    .export-panel {
        position: static;
        grid-column: 1 / -1;
    }

    .format-list {
        grid-template-columns: repeat(4, minmax(0, 1fr));
    }

    .format-option {
        min-height: 54px;
    }
}

@media (max-width: 759px) {
    .app-header {
        grid-template-columns: 1fr auto;
        min-height: 72px;
        padding: 0 16px;
    }

    .brand {
        gap: 10px;
        font-size: 19px;
    }

    .brand-mark {
        width: 36px;
        height: 36px;
    }

    .app-header {
        grid-template-columns: 1fr;
        min-height: auto;
        padding: 0;
    }

    .brand {
        padding: 14px 16px;
    }

    .mode-nav {
        display: grid;
        grid-template-columns: repeat(4, 1fr);
        height: 52px;
        gap: 0;
        border-top: 1px solid var(--border);
        background: rgba(255, 255, 255, .96);
    }

    .mode-nav__item {
        min-width: 0;
        padding: 0 4px;
        font-size: 12.5px;
    }

    .mode-nav__item svg {
        display: none;
    }

    .editor-shell {
        display: flex;
        flex-direction: column;
        gap: 18px;
        min-height: 0;
        padding: 20px 16px 30px;
    }

    .editor-settings {
        display: contents;
    }

    .content-panel { order: 1; }
    .preview-region { order: 2; }
    .style-panel { order: 3; }
    .export-panel { order: 4; }

    .content-panel,
    .style-panel,
    .export-panel {
        padding: 18px;
    }

    .preview-heading {
        min-height: 36px;
        padding: 0 0 10px;
    }

    .preview-canvas {
        min-height: auto;
        aspect-ratio: 1;
        padding: 28px;
        background-size: 22px 22px;
    }

    .preview-stage svg {
        max-height: none;
    }

    .control-grid--colors {
        grid-template-columns: 1fr;
    }

    .upload-zone {
        min-height: 108px;
    }

    .export-panel {
        border: 1px solid var(--border);
    }

    .format-list {
        grid-template-columns: repeat(4, minmax(0, 1fr));
        gap: 8px;
    }

    .format-option {
        display: flex;
        min-width: 0;
        min-height: 64px;
        flex-direction: column;
        justify-content: center;
        gap: 6px;
        padding: 8px 4px;
    }

    .format-option {
        grid-template-columns: none;
    }

    .format-glyph,
    .format-mark {
        display: none;
    }

    .format-option strong {
        font-size: 13px;
    }

    .format-check {
        width: 20px;
        height: 20px;
        font-size: 12px;
    }

    .download-button {
        min-height: 62px;
        margin-top: 16px;
        font-size: 17px;
    }
}

@media (max-width: 420px) {
    .brand span {
        font-size: 17px;
    }

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

    .preview-canvas {
        padding: 20px;
    }
}

@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        scroll-behavior: auto !important;
        transition-duration: .01ms !important;
        animation-duration: .01ms !important;
        animation-iteration-count: 1 !important;
    }
}