:root {
    color-scheme: light;
    --color-canvas: #f4f4f4;
    --color-surface: #ffffff;
    --color-layer: #e8e8e8;
    --color-text: #161616;
    --color-text-muted: #525252;
    --color-border: #c6c6c6;
    --color-primary: #0f62fe;
    --color-primary-hover: #0043ce;
    --color-primary-active: #002d9c;
    --color-selected: #edf5ff;
    --color-error: #da1e28;
    --color-success: #198038;
    --font-sans: "Pretendard", "Noto Sans KR", "Apple SD Gothic Neo", system-ui, sans-serif;
    --duration-fast: 160ms;
    --duration-step: 180ms;
    --ease-out: cubic-bezier(0.2, 0, 0.38, 0.9);
}

* {
    box-sizing: border-box;
}

html {
    min-width: 320px;
    background: var(--color-canvas);
    color: var(--color-text);
    font-family: var(--font-sans);
    scroll-behavior: smooth;
}

body {
    min-height: 100dvh;
    margin: 0;
    background: var(--color-canvas);
    font-size: 16px;
    line-height: 1.5;
}

button,
input,
textarea {
    font: inherit;
}

button,
.button,
.option-tile {
    touch-action: manipulation;
}

.skip-link {
    position: fixed;
    z-index: 10;
    top: 0;
    left: 16px;
    padding: 12px 16px;
    background: var(--color-surface);
    color: var(--color-primary-active);
    transform: translateY(-120%);
}

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

.masthead {
    min-height: 56px;
    background: var(--color-text);
    color: var(--color-surface);
}

.masthead__inner {
    display: flex;
    min-height: 56px;
    max-width: 1280px;
    align-items: center;
    gap: 16px;
    margin: 0 auto;
    padding: 0 24px;
}

.masthead__brand {
    flex: 0 0 auto;
    font-size: 14px;
    font-weight: 600;
    letter-spacing: 1.6px;
    white-space: nowrap;
}

.masthead__divider {
    width: 1px;
    height: 24px;
    background: var(--color-text-muted);
}

.masthead__title {
    overflow: hidden;
    margin: 0;
    font-size: 14px;
    font-weight: 400;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.survey-shell {
    display: grid;
    width: min(100%, 1280px);
    min-height: calc(100dvh - 56px);
    grid-template-columns: 240px minmax(0, 1fr);
    margin: 0 auto;
    background: var(--color-surface);
}

.section-rail {
    padding: 40px 24px;
    border-right: 1px solid var(--color-border);
    background: var(--color-canvas);
}

.section-rail__eyebrow,
.completion-panel__eyebrow {
    margin: 0 0 8px;
    color: var(--color-primary);
    font-size: 12px;
    font-weight: 600;
    letter-spacing: 1.6px;
}

.section-rail__title {
    margin: 0 0 32px;
    font-size: 20px;
    line-height: 28px;
}

.section-rail__list {
    display: grid;
    gap: 24px;
    margin: 0;
    padding: 0;
    list-style: none;
}

.section-rail__item {
    display: grid;
    grid-template-columns: 32px minmax(0, 1fr);
    gap: 8px;
    color: var(--color-text-muted);
}

.section-rail__item.is-active {
    color: var(--color-text);
}

.section-rail__item.is-active .section-rail__number {
    color: var(--color-primary);
}

.section-rail__item.is-complete .section-rail__number {
    color: var(--color-success);
}

.section-rail__number {
    padding-top: 2px;
    font-size: 12px;
    font-variant-numeric: tabular-nums;
    letter-spacing: 0.32px;
}

.section-rail__item strong,
.section-rail__item small {
    display: block;
}

.section-rail__item strong {
    font-size: 14px;
    line-height: 20px;
}

.section-rail__item small {
    margin-top: 4px;
    font-size: 12px;
}

.section-rail__note {
    margin: 48px 0 0;
    color: var(--color-text-muted);
    font-size: 12px;
    line-height: 20px;
    word-break: keep-all;
}

.survey-panel {
    display: flex;
    min-width: 0;
    flex-direction: column;
    padding: 40px 48px;
}

.progress-block {
    width: 100%;
    max-width: 760px;
    margin: 0 auto 48px;
}

.progress-block__labels {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    margin-bottom: 12px;
    color: var(--color-text-muted);
    font-size: 14px;
}

.progress-block__labels strong {
    color: var(--color-primary);
    font-variant-numeric: tabular-nums;
    white-space: nowrap;
}

progress {
    display: block;
    width: 100%;
    height: 4px;
    overflow: hidden;
    border: 0;
    border-radius: 0;
    background: var(--color-layer);
}

progress::-webkit-progress-bar {
    background: var(--color-layer);
}

progress::-webkit-progress-value {
    background: var(--color-primary);
}

progress::-moz-progress-bar {
    background: var(--color-primary);
}

#survey-form,
.questions {
    display: flex;
    min-height: 0;
    flex: 1;
    flex-direction: column;
}

.question-step {
    width: 100%;
    max-width: 760px;
    margin: 0 auto;
    opacity: 1;
    transform: translateY(0);
    transition: opacity var(--duration-step) var(--ease-out), transform var(--duration-step) var(--ease-out);
}

.js .question-step:not(.is-current) {
    display: none;
}

.question-step.is-entering {
    opacity: 0;
    transform: translateY(calc(8px * var(--entry-direction, 1)));
}

html:not(.js) .progress-block {
    display: none;
}

html:not(.js) .question-step {
    margin-bottom: 64px;
    padding-bottom: 64px;
    border-bottom: 1px solid var(--color-border);
}

.question-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 16px;
    color: var(--color-text-muted);
    font-size: 12px;
    font-weight: 600;
    letter-spacing: 0.32px;
}

.question-title {
    max-width: 720px;
    margin: 0;
    font-size: 28px;
    font-weight: 600;
    line-height: 40px;
    word-break: keep-all;
}

.question-title:focus {
    outline: none;
}

.question-helper {
    margin: 12px 0 32px;
    color: var(--color-text-muted);
    word-break: keep-all;
}

.option-group {
    display: grid;
    gap: 8px;
    margin: 0;
    padding: 0;
    border: 0;
}

.option-tile {
    display: flex;
    min-height: 56px;
    align-items: center;
    gap: 16px;
    padding: 12px 16px;
    border: 1px solid var(--color-border);
    background: var(--color-surface);
    cursor: pointer;
    transition: background-color var(--duration-fast) var(--ease-out), border-color var(--duration-fast) var(--ease-out);
}

.option-tile span {
    word-break: keep-all;
}

.option-tile:hover {
    background: var(--color-canvas);
    border-color: var(--color-text-muted);
}

.option-tile:has(.option-input:checked) {
    border-color: var(--color-primary);
    background: var(--color-selected);
}

.option-tile:has(.option-input:focus-visible) {
    outline: 3px solid var(--color-primary);
    outline-offset: 2px;
}

.option-tile:has(.option-input:disabled) {
    cursor: not-allowed;
    opacity: 0.48;
}

.option-input {
    width: 20px;
    height: 20px;
    flex: 0 0 20px;
    margin: 0;
    accent-color: var(--color-primary);
}

.text-field {
    width: 100%;
    min-height: 56px;
    padding: 12px 16px;
    border: 0;
    border-bottom: 2px solid var(--color-text);
    border-radius: 0;
    outline: 2px solid transparent;
    background: var(--color-canvas);
    color: var(--color-text);
}

.text-field:focus {
    border-bottom-color: var(--color-primary);
    outline-color: var(--color-primary);
    outline-offset: 2px;
}

.text-field--area {
    min-height: 192px;
    resize: vertical;
}

.has-error .text-field,
.has-error .option-group {
    border-left: 4px solid var(--color-error);
}

.field-error {
    min-height: 24px;
    margin: 12px 0 0;
    color: var(--color-error);
    font-size: 14px;
    font-weight: 600;
}

.selection-count {
    margin: 12px 0 0;
    color: var(--color-text-muted);
    font-size: 14px;
    text-align: right;
}

.selection-count strong {
    color: var(--color-primary);
    font-variant-numeric: tabular-nums;
}

.survey-actions {
    display: none;
    width: 100%;
    max-width: 760px;
    grid-template-columns: minmax(120px, 1fr) minmax(160px, 2fr);
    gap: 8px;
    margin: 40px auto 0;
    padding-top: 24px;
    border-top: 1px solid var(--color-border);
}

.js .survey-actions,
.no-js-actions {
    display: grid;
}

.no-js-actions {
    width: 100%;
    max-width: 760px;
    margin: 40px auto 0;
    padding-top: 24px;
    border-top: 1px solid var(--color-border);
}

.js .no-js-actions {
    display: none;
}

.button {
    display: inline-flex;
    min-height: 48px;
    align-items: center;
    justify-content: center;
    padding: 12px 24px;
    border: 1px solid transparent;
    border-radius: 0;
    font-weight: 600;
    line-height: 24px;
    text-align: center;
    text-decoration: none;
    white-space: nowrap;
    cursor: pointer;
}

.button:focus-visible {
    outline: 3px solid var(--color-primary);
    outline-offset: 3px;
}

.button:disabled {
    cursor: not-allowed;
    opacity: 0.48;
}

.button--primary {
    background: var(--color-primary);
    color: var(--color-surface);
}

.button--primary:hover:not(:disabled) {
    background: var(--color-primary-hover);
}

.button--primary:active:not(:disabled) {
    background: var(--color-primary-active);
}

.button--secondary {
    border-color: var(--color-text);
    background: var(--color-surface);
    color: var(--color-text);
}

.button--secondary:hover:not(:disabled) {
    background: var(--color-layer);
}

.notice,
.error-summary {
    width: 100%;
    max-width: 760px;
    margin: 0 auto 24px;
    padding: 16px;
    border-left: 4px solid var(--color-error);
    background: var(--color-canvas);
}

.error-summary p {
    margin: 4px 0 0;
    color: var(--color-text-muted);
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    clip-path: inset(50%);
    white-space: nowrap;
}

.completion-page {
    background: var(--color-surface);
}

.completion-shell {
    display: grid;
    min-height: calc(100dvh - 56px);
    place-items: center;
    padding: 48px 24px;
}

.completion-panel {
    width: min(100%, 640px);
}

.completion-panel__rule {
    width: 64px;
    height: 4px;
    margin: 16px 0 32px;
    background: var(--color-success);
}

.completion-panel h2 {
    margin: 0 0 16px;
    font-size: 40px;
    font-weight: 400;
    line-height: 48px;
    word-break: keep-all;
}

.completion-panel p:not(.completion-panel__eyebrow) {
    max-width: 560px;
    margin: 0 0 32px;
    color: var(--color-text-muted);
    word-break: keep-all;
}

.completion-panel__link {
    min-width: 200px;
}

@media (max-width: 1023px) {
    .survey-shell {
        grid-template-columns: minmax(0, 1fr);
    }

    .section-rail {
        display: none;
    }

    .survey-panel {
        padding: 40px 32px;
    }
}

@media (max-width: 599px) {
    .masthead__inner {
        gap: 12px;
        padding: 0 16px;
    }

    .masthead__title {
        font-size: 12px;
    }

    .survey-panel {
        min-height: calc(100dvh - 56px);
        padding: 24px 16px;
    }

    .progress-block {
        margin-bottom: 32px;
    }

    .question-title {
        font-size: 24px;
        line-height: 32px;
    }

    .question-helper {
        margin-bottom: 24px;
    }

    .option-tile {
        min-height: 56px;
        padding: 12px;
    }

    .survey-actions {
        grid-template-columns: 1fr 1.4fr;
        margin-top: 32px;
    }

    .button {
        padding-right: 16px;
        padding-left: 16px;
    }

    .completion-shell {
        place-items: start;
        padding: 64px 24px;
    }

    .completion-panel h2 {
        font-size: 32px;
        line-height: 40px;
    }
}

@media (prefers-reduced-motion: reduce) {
    html {
        scroll-behavior: auto;
    }

    *,
    *::before,
    *::after {
        transition-duration: 0.01ms !important;
    }

    .question-step.is-entering {
        transform: none;
    }
}