:root {
    color-scheme: light;
    --color-primary: #6d28d9;
    --color-primary-strong: #5b21b6;
    --color-primary-soft: #f3e8ff;
    --color-on-primary: #ffffff;
    --color-accent: #7c3aed;
    --color-accent-strong: #6d28d9;
    --color-accent-soft: #ede9fe;
    --color-on-accent: #ffffff;
    --color-violet: #6d28d9;
    --color-violet-soft: #f5f3ff;
    --color-surface: #ffffff;
    --color-background: #faf9ff;
    --color-text: #211832;
    --color-muted: #625a73;
    --color-border: #e6def2;
    --color-danger: #b91c1c;
    --color-danger-soft: #fef2f2;
    --color-success: #166534;
    --color-success-soft: #dcfce7;
    --focus-ring: #7c3aed;
    --radius-sm: 10px;
    --radius-md: 16px;
    --radius-lg: 20px;
    --container: 1180px;
    --motion-fast: 160ms ease;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
    min-width: 320px;
    min-height: 100dvh;
    margin: 0;
    overflow-x: hidden;
    background: var(--color-background);
    color: var(--color-text);
    font-family: "Noto Sans Thai", Thonburi, Tahoma, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    font-size: 16px;
    line-height: 1.6;
}

button, textarea, select { font: inherit; }
button, a, select { -webkit-tap-highlight-color: transparent; }
a { color: inherit; }
svg { display: block; fill: currentColor; }

.container {
    width: min(calc(100% - 32px), var(--container));
    margin-inline: auto;
}

.skip-link {
    position: fixed;
    z-index: 1000;
    top: 12px;
    left: 12px;
    padding: 10px 16px;
    border: 2px solid var(--color-text);
    border-radius: 10px;
    background: var(--color-surface);
    color: var(--color-text);
    font-weight: 700;
    transform: translateY(-160%);
}

.skip-link:focus { transform: translateY(0); }

:focus-visible {
    outline: 3px solid var(--focus-ring);
    outline-offset: 3px;
}

.site-header {
    border-bottom: 1px solid var(--color-border);
    background: rgba(255, 255, 255, 0.96);
}

.header-inner {
    display: flex;
    min-height: 82px;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
}

.brand {
    display: inline-flex;
    min-height: 48px;
    align-items: center;
    gap: 13px;
    color: var(--color-text);
    text-decoration: none;
}

.brand-logo { width: 62px; height: auto; }
.brand-copy { display: grid; line-height: 1.15; }
.brand-copy strong { color: var(--color-text); font-size: 1.05rem; letter-spacing: -0.02em; }
.brand-copy small { margin-top: 4px; color: var(--color-muted); font-size: 0.72rem; font-weight: 700; letter-spacing: 0.08em; }

.privacy-pill {
    display: inline-flex;
    min-height: 44px;
    align-items: center;
    gap: 8px;
    padding: 8px 14px;
    border: 1px solid var(--color-border);
    border-radius: 999px;
    background: var(--color-surface);
    color: var(--color-primary);
    font-size: 0.88rem;
    font-weight: 700;
}

.privacy-pill svg { width: 20px; height: 20px; }
.page-shell { padding-block: 52px 72px; }

.hero {
    max-width: 720px;
    margin: 0 auto 40px;
    text-align: center;
}

.eyebrow {
    display: inline-flex;
    min-height: 36px;
    align-items: center;
    gap: 9px;
    padding: 5px 13px;
    border: 1px solid var(--color-border);
    border-radius: 999px;
    background: var(--color-surface);
    color: var(--color-primary);
    font-size: 0.9rem;
    font-weight: 800;
}

.eyebrow-dot {
    width: 9px;
    height: 9px;
    border-radius: 50%;
    background: var(--color-primary);
}

.hero h1 {
    margin: 20px 0 12px;
    color: var(--color-text);
    font-size: clamp(2.55rem, 6vw, 4.5rem);
    line-height: 1.08;
    letter-spacing: -0.045em;
}

.hero h1 span { color: var(--color-primary); }

.hero > p {
    max-width: 660px;
    margin: 0 auto;
    color: var(--color-muted);
    font-size: clamp(1rem, 2.4vw, 1.2rem);
}

.feature-list {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 10px;
    margin: 24px 0 0;
    padding: 0;
    list-style: none;
}

.feature-list li {
    display: inline-flex;
    min-height: 40px;
    align-items: center;
    gap: 7px;
    padding: 7px 12px;
    border: 1px solid #eadcff;
    border-radius: 999px;
    background: var(--color-primary-soft);
    color: var(--color-primary-strong);
    font-size: 0.9rem;
    font-weight: 700;
}

.feature-list svg { width: 19px; height: 19px; }

.workspace {
    display: grid;
    grid-template-columns: minmax(0, 1.08fr) minmax(350px, 0.92fr);
    gap: 24px;
    align-items: stretch;
}

.panel {
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    background: var(--color-surface);
    box-shadow: 0 16px 40px rgba(76, 29, 149, 0.06);
}

.form-panel, .preview-panel { padding: clamp(22px, 3vw, 34px); }

.panel-heading {
    display: flex;
    align-items: center;
    gap: 13px;
    margin-bottom: 28px;
}

.panel-heading h2 { margin: 0; font-size: 1.25rem; line-height: 1.3; }
.panel-heading p { margin: 3px 0 0; color: var(--color-muted); font-size: 0.9rem; }

.step-number {
    display: grid;
    flex: 0 0 42px;
    width: 42px;
    height: 42px;
    place-items: center;
    border-radius: 13px;
    background: var(--color-primary);
    color: var(--color-on-primary);
    font-weight: 800;
}

.step-number--soft { background: var(--color-primary-soft); color: var(--color-primary-strong); }

.alert {
    display: flex;
    gap: 12px;
    margin-bottom: 20px;
    padding: 14px 16px;
    border: 1px solid #fca5a5;
    border-radius: var(--radius-sm);
}

.alert--error { background: var(--color-danger-soft); color: var(--color-danger); }
.alert svg { flex: 0 0 22px; width: 22px; height: 22px; margin-top: 2px; }
.alert strong, .alert a { display: block; }
.alert a { margin-top: 2px; font-size: 0.92rem; }
.field-group + .field-group { margin-top: 20px; }

.label-row {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    gap: 12px;
}

label { display: block; margin-bottom: 8px; font-weight: 800; }
label span { color: var(--color-danger); }

.byte-counter {
    color: var(--color-muted);
    font-size: 0.82rem;
    font-variant-numeric: tabular-nums;
}

.byte-counter.is-over-limit { color: var(--color-danger); font-weight: 800; }

textarea, select {
    width: 100%;
    border: 1px solid #cfc2e3;
    border-radius: var(--radius-sm);
    background: #ffffff;
    color: var(--color-text);
    transition: border-color var(--motion-fast), background-color var(--motion-fast);
}

textarea {
    min-height: 148px;
    padding: 14px 16px;
    line-height: 1.6;
    resize: vertical;
}

textarea::placeholder { color: #777083; opacity: 1; }
textarea:hover, select:hover { border-color: var(--color-primary); }
textarea[aria-invalid="true"] { border-color: var(--color-danger); background: #fffafa; }

.helper-text, .field-error { margin: 7px 0 0; font-size: 0.84rem; line-height: 1.5; }
.helper-text { color: var(--color-muted); }
.field-error { color: var(--color-danger); font-weight: 700; }

.option-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
    margin-top: 22px;
}

.option-grid .field-group + .field-group { margin-top: 0; }
.select-wrap { position: relative; }

select {
    min-height: 48px;
    padding: 10px 42px 10px 13px;
    appearance: none;
    cursor: pointer;
}

.select-wrap svg {
    position: absolute;
    top: 50%;
    right: 12px;
    width: 22px;
    height: 22px;
    pointer-events: none;
    transform: translateY(-50%);
}

.button {
    display: inline-flex;
    min-height: 52px;
    align-items: center;
    justify-content: center;
    gap: 10px;
    border: 0;
    border-radius: 14px;
    padding: 12px 20px;
    color: var(--color-on-primary);
    font-weight: 800;
    text-decoration: none;
    cursor: pointer;
    transition: background-color var(--motion-fast), opacity var(--motion-fast);
}

.button:active { opacity: 0.84; }
.button svg { width: 23px; height: 23px; }
.button--primary { width: 100%; margin-top: 26px; background: var(--color-primary); }
.button--primary:hover { background: var(--color-primary-strong); }
.button--primary[disabled] { cursor: wait; opacity: 0.64; }

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

.preview-stage {
    position: relative;
    display: grid;
    min-height: 386px;
    flex: 1;
    place-items: center;
    overflow: hidden;
    border: 2px dashed #cbb8e9;
    border-radius: var(--radius-md);
    background: #fcfaff;
}

.preview-stage--ready { border-style: solid; border-color: var(--color-primary); background: #ffffff; }

.empty-preview {
    display: grid;
    max-width: 300px;
    justify-items: center;
    padding: 34px 22px;
    text-align: center;
}

.empty-icon {
    display: grid;
    width: 118px;
    height: 118px;
    margin-bottom: 18px;
    place-items: center;
    border: 12px solid var(--color-primary-soft);
    border-radius: 24px;
    background: #ffffff;
    color: var(--color-primary);
}

.empty-icon svg { width: 72px; height: 72px; }
.empty-preview strong { font-size: 1.1rem; }
.empty-preview span { margin-top: 5px; color: var(--color-muted); font-size: 0.9rem; }

.success-badge {
    position: absolute;
    top: 14px;
    right: 14px;
    display: inline-flex;
    min-height: 36px;
    align-items: center;
    gap: 6px;
    padding: 5px 10px;
    border-radius: 999px;
    background: var(--color-success-soft);
    color: var(--color-success);
    font-size: 0.82rem;
    font-weight: 800;
}

.success-badge svg { width: 18px; height: 18px; }

.qr-preview {
    display: block;
    width: min(84%, 360px);
    height: auto;
    aspect-ratio: 1;
    object-fit: contain;
}

.download-form { margin-top: 18px; }
.button--download { width: 100%; background: var(--color-primary); color: var(--color-on-primary); }
.button--download:hover { background: var(--color-primary-strong); }

.download-placeholder {
    display: grid;
    min-height: 52px;
    margin-top: 18px;
    place-items: center;
    border-radius: 14px;
    background: #f0edf5;
    color: #6d6678;
    font-weight: 700;
}

.scan-tip {
    display: flex;
    align-items: flex-start;
    gap: 7px;
    margin: 12px 0 0;
    color: var(--color-muted);
    font-size: 0.82rem;
}

.scan-tip svg { flex: 0 0 18px; width: 18px; height: 18px; margin-top: 2px; }

.security-note {
    display: flex;
    max-width: 820px;
    align-items: center;
    gap: 16px;
    margin: 24px auto 0;
    padding: 18px 20px;
    border: 1px solid #ddd0f5;
    border-radius: var(--radius-md);
    background: var(--color-violet-soft);
    color: #4c1d95;
}

.security-icon {
    display: grid;
    flex: 0 0 48px;
    width: 48px;
    height: 48px;
    place-items: center;
    border-radius: 14px;
    background: #ffffff;
}

.security-icon svg { width: 28px; height: 28px; }
.security-note h2 { margin: 0; font-size: 1rem; }
.security-note p { margin: 3px 0 0; font-size: 0.88rem; }

.site-footer {
    padding: 26px 0 30px;
    border-top: 1px solid var(--color-border);
    background: #ffffff;
    color: var(--color-muted);
    font-size: 0.84rem;
}

.site-footer p { margin: 0; }

.footer-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
}

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

.developer-credit img { width: 54px; height: auto; }
.developer-credit div { display: grid; line-height: 1.4; }
.developer-credit span { font-size: 0.78rem; }
.developer-credit strong { color: var(--color-text); font-size: 0.9rem; }

.visitor-count {
    display: inline-flex;
    min-height: 42px;
    align-items: center;
    gap: 6px;
    padding: 7px 12px;
    border: 1px solid var(--color-border);
    border-radius: 999px;
    background: var(--color-violet-soft);
    color: var(--color-muted);
    font-variant-numeric: tabular-nums;
    white-space: nowrap;
}

.visitor-count svg { width: 18px; height: 18px; color: var(--color-primary); }
.visitor-count strong { color: var(--color-primary-strong); font-size: 0.96rem; }

@media (max-width: 860px) {
    .workspace { grid-template-columns: 1fr; }
    .preview-stage { min-height: 420px; }
}

@media (max-width: 560px) {
    .container { width: min(calc(100% - 24px), var(--container)); }
    .header-inner { min-height: 74px; }
    .brand-logo { width: 54px; }

    .privacy-pill span {
        position: absolute;
        width: 1px;
        height: 1px;
        overflow: hidden;
        clip: rect(0 0 0 0);
        white-space: nowrap;
    }

    .privacy-pill { width: 44px; padding: 0; justify-content: center; }
    .page-shell { padding-block: 38px 48px; }
    .hero { margin-bottom: 30px; }
    .hero h1 { font-size: clamp(2.5rem, 14vw, 4rem); }
    .hero > p { font-size: 1rem; }
    .feature-list { gap: 8px; }
    .feature-list li { font-size: 0.82rem; }
    .panel { border-radius: 18px; }
    .form-panel, .preview-panel { padding: 20px 16px; }
    .panel-heading { margin-bottom: 22px; }
    .option-grid { grid-template-columns: 1fr; }
    .option-grid .field-group + .field-group { margin-top: 2px; }
    .preview-stage { min-height: 330px; }
    .success-badge { top: 10px; right: 10px; }
    .security-note { align-items: flex-start; padding: 16px; }
    .footer-inner { flex-direction: column; align-items: stretch; gap: 18px; }
    .developer-credit { justify-content: center; text-align: left; }
    .visitor-count { align-self: center; }
}

@media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; }
    *, *::before, *::after {
        scroll-behavior: auto !important;
        transition-duration: 0.01ms !important;
    }
}