:root {
    --surface-page: #f5f5f2;
    --surface-card: #ffffff;
    --surface-subtle: #f0f0ec;
    --surface-hover: #e9e9e4;
    --surface-inverse: #1b1b19;

    --line-subtle: #e3e3de;
    --line-default: #d2d2cc;
    --line-strong: #a7a7a0;

    --text-primary: #1b1b19;
    --text-secondary: #5f5f59;
    --text-tertiary: #7a7a73;
    --text-inverse: #ffffff;

    --status-success: #087f5b;
    --status-danger: #c92a2a;
    --status-warning: #a55b00;
    --status-neutral: #55554f;
    --status-focus: #111111;

    --space-1: 4px;
    --space-2: 8px;
    --space-3: 12px;
    --space-4: 16px;
    --space-5: 24px;
    --space-6: 32px;
    --space-7: 48px;

    --font-sans: -apple-system, BlinkMacSystemFont, "Pretendard", "Noto Sans KR", "Segoe UI", sans-serif;
    --font-mono: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
    --font-size-small: 13px;
    --font-size-body: 15px;
    --font-size-reading: 16px;
    --font-size-title: clamp(26px, 4vw, 34px);
    --line-height-body: 1.6;
    --line-height-reading: 1.82;

    --radius-xs: 2px;
    --radius-sm: 4px;
    --radius-md: 6px;

    --content-width: 1120px;
    --reading-width: 820px;
    --control-height: 40px;

    --color-bg: var(--surface-page);
    --color-card: var(--surface-card);
    --color-border: var(--line-default);
    --color-border-light: var(--line-subtle);
    --color-table-head: var(--surface-subtle);
    --color-code-bg: var(--surface-subtle);
    --color-text: var(--text-primary);
    --color-muted: var(--text-secondary);
    --color-strong: var(--text-primary);
    --color-primary: var(--surface-inverse);
    --color-primary-hover: var(--status-focus);
    --color-accepted: var(--status-success);
    --color-error: var(--status-danger);
    --color-warning: var(--status-warning);
    --color-purple: var(--status-danger);
    --color-pending: var(--status-warning);
    --color-system: var(--status-neutral);
}

html {
    min-width: 320px;
    background: var(--surface-page);
    color-scheme: light;
    scroll-behavior: smooth;
}

body {
    min-height: 100vh;
    background: var(--surface-page);
    color: var(--text-primary);
    font-family: var(--font-sans);
    font-size: var(--font-size-body);
    line-height: var(--line-height-body);
    text-rendering: optimizeLegibility;
}

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

button,
a,
input,
select,
textarea,
summary,
[tabindex] {
    -webkit-tap-highlight-color: transparent;
}

a {
    color: var(--text-primary);
    text-underline-offset: 3px;
}

a:hover {
    color: var(--text-primary);
}

:focus {
    outline: none;
}

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

::selection {
    background: var(--surface-inverse);
    color: var(--text-inverse);
}

.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;
}

.skip-link {
    position: fixed;
    z-index: 2000;
    top: var(--space-3);
    left: var(--space-3);
    padding: var(--space-2) var(--space-3);
    border: 1px solid var(--surface-inverse);
    border-radius: var(--radius-xs);
    background: var(--surface-card);
    color: var(--text-primary);
    font-weight: 800;
    transform: translateY(-160%);
}

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

.container {
    width: min(100%, var(--content-width));
    margin: 0 auto;
    padding: var(--space-6) var(--space-5) var(--space-7);
}

.container > * + * {
    margin-top: var(--space-5);
}

.card {
    padding: var(--space-5);
    border: 1px solid var(--line-default);
    border-radius: var(--radius-sm);
    background: var(--surface-card);
}

.page-title,
.home-title,
.problem-title-main,
.profile-title {
    color: var(--text-primary);
    letter-spacing: -0.035em;
    line-height: 1.2;
}

.page-title {
    margin: 0 0 var(--space-5);
    font-size: 28px;
    font-weight: 850;
}

.empty,
.empty-profile-text {
    color: var(--text-secondary);
}

/* Header */

.header {
    border-bottom: 1px solid var(--line-default);
    background: var(--surface-card);
}

.header-inner {
    width: min(100%, var(--content-width));
    min-height: 72px;
    margin: 0 auto;
    padding: var(--space-3) var(--space-5);
    gap: var(--space-5);
}

.site-brand {
    flex: 0 0 auto;
    gap: 0;
}

.site-brand-main {
    font-size: 27px;
    font-weight: 900;
    letter-spacing: -0.05em;
}

.site-brand-sub {
    color: var(--text-secondary);
    font-size: 10px;
    letter-spacing: 0.12em;
}

.header-right {
    min-width: 0;
    gap: var(--space-5);
}

.nav {
    min-width: 0;
    gap: var(--space-4);
}

.nav a {
    min-height: 36px;
    padding: 8px 0 7px;
    border-bottom: 2px solid transparent;
    color: var(--text-secondary);
    font-size: 14px;
    font-weight: 700;
    white-space: nowrap;
}

.nav a:hover {
    border-bottom-color: var(--line-strong);
    color: var(--text-primary);
}

.nav a.active,
.nav a[aria-current="page"] {
    border-bottom-color: var(--surface-inverse);
    color: var(--text-primary);
    font-weight: 850;
}

.auth-area {
    gap: var(--space-2);
}

.login-button,
.logout-button,
.admin-badge {
    min-height: 34px;
    border: 1px solid var(--line-default);
    border-radius: var(--radius-xs);
    background: var(--surface-card);
    color: var(--text-primary);
}

.login-button,
.logout-button {
    display: inline-flex;
    align-items: center;
    padding: 6px 10px;
}

.login-button:hover,
.logout-button:hover {
    background: var(--surface-subtle);
}

.admin-badge {
    display: inline-flex;
    align-items: center;
    min-height: 28px;
    padding: 4px 7px;
    color: var(--text-secondary);
    font-size: 12px;
    font-weight: 800;
}

.user-link {
    overflow: hidden;
    max-width: 180px;
    text-overflow: ellipsis;
}

/* Actions and fields */

.button-primary,
.button-primary-link,
.button-secondary-link,
.copy-button,
.problem-edit-request-button {
    min-height: var(--control-height);
    padding: 9px 15px;
    border-radius: var(--radius-xs);
    font-weight: 800;
    line-height: 1.35;
}

.button-primary,
.button-primary-link {
    border: 1px solid var(--surface-inverse);
    background: var(--surface-inverse);
    color: var(--text-inverse);
}

.button-primary:hover,
.button-primary-link:hover {
    border-color: var(--status-focus);
    background: var(--status-focus);
    color: var(--text-inverse);
}

.button-secondary-link,
.copy-button,
.problem-edit-request-button {
    border: 1px solid var(--line-default);
    background: var(--surface-card);
    color: var(--text-primary);
}

.button-secondary-link:hover,
.copy-button:hover,
.problem-edit-request-button:hover {
    background: var(--surface-subtle);
    color: var(--text-primary);
}

button:disabled,
input:disabled,
select:disabled,
textarea:disabled,
[aria-disabled="true"] {
    cursor: not-allowed;
    opacity: 0.48;
}

input,
select,
textarea,
.code-input,
.language-search,
.profile-description-input,
.statement-textarea,
.request-admin-message {
    border: 1px solid var(--line-default);
    border-radius: var(--radius-xs);
    background: var(--surface-card);
    color: var(--text-primary);
}

input,
select {
    min-height: var(--control-height);
    padding: 8px 10px;
}

textarea,
.code-input,
.profile-description-input,
.statement-textarea,
.request-admin-message {
    padding: var(--space-3);
    line-height: 1.6;
}

input::placeholder,
textarea::placeholder {
    color: var(--text-tertiary);
    opacity: 1;
}

input:hover,
select:hover,
textarea:hover {
    border-color: var(--line-strong);
}

input:focus-visible,
select:focus-visible,
textarea:focus-visible {
    border-color: var(--surface-inverse);
    outline-offset: 2px;
}

.form-row {
    gap: var(--space-3);
    margin-bottom: var(--space-3);
}

.form-row label,
.profile-description-label,
.problem-filter-label,
.problem-filter-row label {
    color: var(--text-primary);
    font-weight: 800;
}

.form-help,
.contributor-description {
    color: var(--text-secondary);
}

.submit-actions {
    margin-top: var(--space-4);
}

/* Tables */

.table-scroll,
.ranking-table-wrap,
.profile-language-table-wrap {
    width: 100%;
    overflow-x: auto;
    overscroll-behavior-inline: contain;
    border: 1px solid var(--line-default);
    border-radius: var(--radius-xs);
}

.table-scroll table,
.ranking-table-wrap table,
.profile-language-table-wrap table {
    border: 0;
}

.info-table,
.problem-table,
.submission-table,
.ranking-table,
.profile-language-table {
    background: var(--surface-card);
}

.info-table th,
.info-table td,
.problem-table th,
.problem-table td,
.submission-table th,
.submission-table td,
.ranking-table th,
.ranking-table td,
.profile-language-table th,
.profile-language-table td {
    padding: 12px 13px;
    border-bottom: 1px solid var(--line-subtle);
    vertical-align: middle;
}

.info-table thead th,
.problem-table thead th,
.submission-table thead th,
.ranking-table thead th,
.profile-language-table thead th {
    background: var(--surface-subtle);
    color: var(--text-secondary);
    font-size: var(--font-size-small);
    font-weight: 850;
}

.problem-table tbody tr:hover td,
.submission-table tbody tr:hover td,
.ranking-table tbody tr:hover td,
.profile-language-table tbody tr:hover td {
    background: var(--surface-subtle);
}

.info-table tbody tr:last-child > *,
.problem-table tbody tr:last-child > *,
.submission-table tbody tr:last-child > *,
.ranking-table tbody tr:last-child > *,
.profile-language-table tbody tr:last-child > * {
    border-bottom: 0;
}

/* Neutral labels, tags and current selection */

.problem-tag,
.problem-tag-more,
.test-sample-badge,
.request-test-group-count,
.polygon-test-no {
    display: inline-flex;
    align-items: center;
    min-height: 24px;
    padding: 3px 7px;
    border: 1px solid var(--line-default);
    border-radius: var(--radius-xs);
    background: var(--surface-subtle);
    color: var(--text-secondary);
    font-size: 12px;
    font-weight: 750;
    line-height: 1.3;
}

.problem-tag-more {
    border-color: transparent;
    background: transparent;
}

.tab-menu,
.profile-tabs,
.request-editor-tabs,
.statement-view-actions {
    gap: var(--space-4);
    border-bottom: 1px solid var(--line-default);
}

.tab-menu a,
.profile-tab,
.request-editor-tabs a,
.statement-view-actions .button-secondary-link {
    min-height: 40px;
    padding: 9px 1px 8px;
    border: 0;
    border-bottom: 2px solid transparent;
    border-radius: 0;
    background: transparent;
    color: var(--text-secondary);
}

.tab-menu a:hover,
.profile-tab:hover,
.request-editor-tabs a:hover,
.statement-view-actions .button-secondary-link:hover {
    border-bottom-color: var(--line-strong);
    background: transparent;
    color: var(--text-primary);
}

.tab-menu a.active,
.profile-tab.active,
.request-editor-tabs a.active,
.statement-view-actions .active,
[role="tab"][aria-selected="true"] {
    border-color: var(--surface-inverse);
    background: transparent;
    color: var(--text-primary);
}

/* Home */

.home-hero {
    align-items: flex-end;
    margin-bottom: 0;
    padding-block: var(--space-6);
}

.home-title {
    margin: 0 0 var(--space-3);
    font-size: var(--font-size-title);
    font-weight: 900;
}

.home-description {
    max-width: 680px;
    color: var(--text-secondary);
    line-height: 1.72;
}

.home-actions {
    gap: var(--space-2);
}

.home-stats {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 0;
    margin-bottom: 0;
    overflow: hidden;
    border: 1px solid var(--line-default);
    border-radius: var(--radius-sm);
    background: var(--surface-card);
}

.stat-card {
    padding: var(--space-5);
    border: 0;
    border-right: 1px solid var(--line-default);
    border-radius: 0;
    background: transparent;
}

.stat-card:last-child {
    border-right: 0;
}

.stat-value {
    color: var(--text-primary);
    font-variant-numeric: tabular-nums;
}

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

.info-card h2,
.profile-problem-card h2,
.request-admin-section h2,
.card > form > h2,
.card > section > h2 {
    color: var(--text-primary);
}

.info-card p,
.info-list {
    line-height: 1.72;
}

/* Problem list */

.problem-filter-panel {
    margin-bottom: var(--space-5);
    padding: var(--space-4);
    border: 1px solid var(--line-default);
    border-radius: var(--radius-xs);
    background: var(--surface-subtle);
}

.problem-filter-summary {
    min-height: 36px;
    color: var(--text-primary);
}

.problem-filter-row {
    gap: var(--space-3);
}

.problem-filter-actions {
    gap: var(--space-3);
}

.difficulty-range-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-3);
    margin-bottom: var(--space-2);
}

.difficulty-range-selected {
    color: var(--text-secondary);
    font-size: var(--font-size-small);
    font-weight: 800;
    white-space: nowrap;
}

.difficulty-range-slider {
    --range-left: 0%;
    --range-right: 100%;
    position: relative;
    height: 38px;
}

.difficulty-range-slider::before,
.difficulty-range-slider::after {
    content: "";
    position: absolute;
    top: 16px;
    height: 6px;
    border-radius: var(--radius-xs);
}

.difficulty-range-slider::before {
    right: 0;
    left: 0;
    background: var(--line-default);
}

.difficulty-range-slider::after {
    right: calc(100% - var(--range-right));
    left: var(--range-left);
    background: var(--surface-inverse);
}

.difficulty-range-slider input[type="range"] {
    position: absolute;
    z-index: 2;
    top: 2px;
    left: 0;
    width: 100%;
    margin: 0;
    padding: 0;
    appearance: none;
    background: transparent;
    pointer-events: none;
}

.difficulty-range-slider input[type="range"]::-webkit-slider-runnable-track {
    height: 32px;
    background: transparent;
}

.difficulty-range-slider input[type="range"]::-webkit-slider-thumb {
    width: 20px;
    height: 20px;
    margin-top: 6px;
    appearance: none;
    border: 2px solid var(--surface-inverse);
    border-radius: 50%;
    background: var(--surface-card);
    cursor: pointer;
    pointer-events: auto;
}

.difficulty-range-slider input[type="range"]::-moz-range-track {
    height: 32px;
    background: transparent;
}

.difficulty-range-slider input[type="range"]::-moz-range-thumb {
    width: 18px;
    height: 18px;
    border: 2px solid var(--surface-inverse);
    border-radius: 50%;
    background: var(--surface-card);
    cursor: pointer;
    pointer-events: auto;
}

.difficulty-range-scale {
    display: flex;
    justify-content: space-between;
    color: var(--text-tertiary);
    font-size: 12px;
}

.problem-table {
    min-width: 700px;
}

.problem-table .col-tags {
    width: 230px;
}

.problem-table .problem-tags {
    display: flex;
    flex-wrap: nowrap;
    align-items: center;
    overflow: hidden;
    max-width: 230px;
}

.problem-table .problem-tag {
    overflow: hidden;
    max-width: 165px;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.problem-title {
    display: inline-block;
    overflow-wrap: anywhere;
    font-weight: 800;
}

.solved-mark {
    color: var(--status-success);
}

/* Problem detail and submission flow */

.problem-card {
    padding: var(--space-6);
}

.problem-header {
    margin-bottom: var(--space-6);
    padding-bottom: var(--space-5);
    text-align: left;
}

.problem-title-main {
    margin: 0 0 var(--space-4);
    font-size: var(--font-size-title);
    font-weight: 900;
    overflow-wrap: anywhere;
}

.problem-meta {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-2) var(--space-5);
    margin: 0;
    color: var(--text-secondary);
    font-size: 14px;
}

.problem-meta > div {
    display: flex;
    gap: var(--space-2);
}

.problem-meta dt,
.problem-meta dd {
    margin: 0;
}

.problem-meta dt {
    color: var(--text-tertiary);
}

.problem-meta dd {
    color: var(--text-primary);
    font-weight: 800;
}

.problem-tags-center {
    justify-content: flex-start;
    margin-top: var(--space-4);
}

.problem-body,
.statement-preview {
    max-width: var(--reading-width);
}

.problem-section {
    margin: var(--space-7) 0;
}

.problem-section h2,
.sample-title-row h2 {
    font-size: 22px;
    letter-spacing: -0.02em;
}

.problem-text,
.statement-preview-content {
    color: var(--text-primary);
    font-size: var(--font-size-reading);
    line-height: var(--line-height-reading);
    overflow-wrap: anywhere;
}

.problem-text code,
.statement-preview-content code,
.info-list code,
.info-table code {
    border-radius: var(--radius-xs);
    background: var(--surface-subtle);
    color: var(--text-primary);
    font-family: var(--font-mono);
}

.problem-text pre,
.sample-box,
.source-code,
.judge-error-message,
.admin-test-file-content,
.admin-statement-raw pre {
    border: 1px solid var(--line-default);
    border-radius: var(--radius-xs);
    background: var(--surface-subtle);
    font-family: var(--font-mono);
}

.sample-title-row {
    margin-bottom: var(--space-3);
    padding-bottom: var(--space-2);
}

.copy-button {
    min-height: 34px;
    padding: 6px 10px;
    font-size: 12px;
}

.copy-button.copied {
    background: var(--surface-inverse);
    color: var(--text-inverse);
}

.submit-card {
    max-width: var(--reading-width);
    margin-inline: auto;
}

.submit-card > h2 {
    margin: 0 0 var(--space-5);
}

.submit-card .form-row {
    align-items: flex-start;
}

.submit-card .form-row label {
    min-width: 72px;
    padding-top: 9px;
}

.submit-card .language-picker,
.submit-card .language-search {
    width: min(100%, 300px);
}

.language-options {
    width: min(100%, 300px);
    border: 1px solid var(--line-strong);
    border-radius: var(--radius-xs);
    background: var(--surface-card);
    box-shadow: none;
}

.language-option {
    min-height: 38px;
    color: var(--text-primary);
}

.language-option:hover,
.language-option.selected,
.language-option[aria-selected="true"] {
    background: var(--surface-subtle);
    color: var(--text-primary);
}

.CodeMirror {
    min-height: 430px;
    border: 1px solid var(--line-default);
    border-radius: var(--radius-xs);
    font-family: var(--font-mono);
}

.CodeMirror-focused {
    border-color: var(--surface-inverse);
    outline: 3px solid var(--status-focus);
    outline-offset: 2px;
}

.CodeMirror-gutters,
.CodeMirror-activeline-background {
    background: var(--surface-subtle);
}

/* Submission pages */

.submission-table {
    min-width: 940px;
}

.status {
    color: var(--text-primary);
    font-weight: 850;
}

.status-accepted {
    color: var(--status-success);
}

.status-wrong_answer,
.status-runtime_error,
.status-compile_error,
.status-time_limit_exceeded,
.status-memory_limit_exceeded {
    color: var(--status-danger);
}

.status-waiting,
.status-running {
    color: var(--status-warning);
}

.status-system_error {
    color: var(--status-neutral);
}

.submission-meta {
    gap: 0;
    overflow: hidden;
    border: 1px solid var(--line-default);
    border-radius: var(--radius-xs);
}

.submission-meta > div {
    padding: var(--space-3) var(--space-4);
    border: 0;
    border-bottom: 1px solid var(--line-subtle);
    border-radius: 0;
    background: var(--surface-card);
}

.submission-meta > div:nth-last-child(-n + 2) {
    border-bottom: 0;
}

.submission-meta a,
.profile-problem-id,
.ranking-solved {
    color: var(--text-primary);
}

.judge-error-message {
    background: var(--surface-inverse);
    color: var(--text-inverse);
}

/* Profile */

.profile-card,
.profile-problem-card,
.profile-language-card {
    max-width: 900px;
}

.profile-avatar,
.ranking-avatar {
    border-color: var(--line-default);
    background: var(--surface-subtle);
}

.profile-tabs {
    justify-content: flex-start;
    margin-top: var(--space-5);
}

.profile-description {
    padding: var(--space-4);
    border: 1px solid var(--line-default);
    border-radius: var(--radius-xs);
    background: var(--surface-card);
}

.profile-stats,
.profile-result-stats {
    gap: 0;
    overflow: hidden;
    border: 1px solid var(--line-default);
    border-radius: var(--radius-xs);
    background: var(--surface-card);
}

.profile-stat,
.profile-result-stat {
    padding: var(--space-4) var(--space-3);
    border: 0;
    border-right: 1px solid var(--line-subtle);
    border-radius: 0;
    background: transparent;
}

.profile-stat:last-child,
.profile-result-stat:last-child {
    border-right: 0;
}

.profile-stat:hover {
    background: var(--surface-subtle);
}

.profile-problem-list {
    gap: 0;
    border-top: 1px solid var(--line-default);
}

.profile-problem-item {
    padding: 11px 8px;
    border: 0;
    border-bottom: 1px solid var(--line-subtle);
    border-radius: 0;
    background: transparent;
}

.profile-problem-item:hover {
    background: var(--surface-subtle);
}

/* Problem request and operational forms */

.request-form {
    max-width: 920px;
}

.request-form > .form-row {
    display: grid;
    grid-template-columns: 180px minmax(0, 1fr);
    align-items: center;
}

.request-form > .form-row label {
    min-width: 0;
}

.request-form > .form-row input,
.request-form > .form-row select {
    width: 100%;
    min-width: 0;
}

.request-field-section {
    margin-top: var(--space-6);
}

.request-field-section h2 {
    margin: 0 0 var(--space-2);
    font-size: 18px;
}

.request-field-section .code-input {
    min-height: 180px;
}

.request-modal-backdrop {
    padding: var(--space-4);
    background: var(--text-secondary);
}

.request-modal {
    width: min(760px, 100%);
    padding: var(--space-5);
    border: 1px solid var(--line-strong);
    border-radius: var(--radius-sm);
    background: var(--surface-card);
    box-shadow: none;
}

.request-modal-close {
    border-radius: var(--radius-xs);
}

.notice-box,
.request-review-grid > div,
.polygon-test-row,
.contributor-guide-step,
.source-file-row,
.statement-preview {
    border: 1px solid var(--line-default);
    border-radius: var(--radius-xs);
    background: var(--surface-card);
}

.invocation-success {
    border-left: 4px solid var(--status-success);
    background: var(--surface-card);
}

.invocation-failure {
    border-left: 4px solid var(--status-danger);
    background: var(--surface-card);
}

/* Pagination */

.pagination {
    flex-wrap: wrap;
    gap: var(--space-1);
}

.pagination a,
.pagination .pagination-page,
.pagination .pagination-nav {
    min-width: 36px;
    min-height: 36px;
    padding: 7px 9px;
    border: 1px solid transparent;
    border-radius: var(--radius-xs);
    background: transparent;
    color: var(--text-secondary);
    text-align: center;
}

.pagination a:hover {
    border-color: var(--line-default);
    background: var(--surface-subtle);
}

.pagination .pagination-page.active,
.pagination [aria-current="page"] {
    border-color: var(--surface-inverse);
    background: var(--surface-inverse);
    color: var(--text-inverse);
}

/* Responsive */

@media (max-width: 900px) {
    .header-inner {
        align-items: flex-start;
        flex-direction: column;
        gap: var(--space-3);
    }

    .header-right {
        width: 100%;
        align-items: flex-start;
        flex-direction: column;
        gap: var(--space-2);
    }

    .nav {
        width: 100%;
        overflow-x: auto;
        flex-wrap: nowrap;
        padding-bottom: 2px;
        scrollbar-width: thin;
    }

    .auth-area {
        width: 100%;
        flex-wrap: wrap;
    }

    .problem-filter-row {
        grid-template-columns: 1fr;
    }

    .home-hero {
        align-items: flex-start;
        flex-direction: column;
    }

    .home-actions {
        width: 100%;
    }

    .submission-meta {
        grid-template-columns: 1fr;
    }

    .submission-meta > div:nth-last-child(-n + 2) {
        border-bottom: 1px solid var(--line-subtle);
    }

    .submission-meta > div:last-child {
        border-bottom: 0;
    }
}

@media (max-width: 720px) {
    .container {
        padding: var(--space-5) var(--space-3) var(--space-7);
    }

    .card,
    .problem-card {
        padding: var(--space-4);
    }

    .home-stats {
        grid-template-columns: 1fr;
    }

    .stat-card {
        border-right: 0;
        border-bottom: 1px solid var(--line-default);
    }

    .stat-card:last-child {
        border-bottom: 0;
    }

    .problem-header {
        margin-bottom: var(--space-5);
    }

    .problem-meta {
        display: grid;
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .problem-meta > div {
        flex-direction: column;
        gap: 0;
    }

    .problem-text,
    .statement-preview-content {
        font-size: 15px;
        line-height: 1.78;
    }

    .submit-card .form-row {
        align-items: stretch;
        flex-direction: column;
    }

    .submit-card .form-row label {
        min-width: 0;
        padding-top: 0;
    }

    .submit-card .language-picker,
    .submit-card .language-search,
    .language-options {
        width: 100%;
    }

    .profile-stats,
    .profile-result-stats {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .profile-stat,
    .profile-result-stat {
        border-right: 1px solid var(--line-subtle);
        border-bottom: 1px solid var(--line-subtle);
    }

    .request-form > .form-row {
        grid-template-columns: 1fr;
        gap: var(--space-2);
    }

    .request-modal {
        max-height: calc(100vh - 32px);
        padding: var(--space-4);
    }

    .home-actions .button-primary-link,
    .home-actions .button-secondary-link,
    .submission-page-actions .button-secondary-link {
        flex: 1;
        width: auto;
        text-align: center;
    }
}

@media (max-width: 560px) {
    .header-inner {
        min-height: 0;
        padding: var(--space-3);
    }

    .container {
        padding-inline: var(--space-2);
    }

    .card,
    .problem-card {
        border-radius: var(--radius-xs);
    }

    .page-title {
        font-size: 25px;
    }

    .home-actions,
    .problem-filter-actions,
    .source-title-row,
    .submission-page-actions,
    .request-modal-actions {
        align-items: stretch;
        flex-direction: column;
    }

    .home-actions .button-primary-link,
    .home-actions .button-secondary-link,
    .problem-filter-actions .button-primary,
    .submission-page-actions .button-secondary-link,
    .request-modal-actions > * {
        width: 100%;
        text-align: center;
    }

    .problem-meta {
        grid-template-columns: 1fr;
    }

    .problem-section {
        margin: var(--space-6) 0;
    }

    .problem-section h2,
    .sample-title-row h2 {
        font-size: 20px;
    }

    .sample-title-row {
        align-items: center;
    }

    .CodeMirror {
        height: 360px !important;
        min-height: 360px;
    }

    .profile-header {
        align-items: center;
    }

    .profile-tabs,
    .request-editor-tabs,
    .tab-menu {
        width: 100%;
        overflow-x: auto;
        flex-wrap: nowrap;
    }

    .profile-problem-item {
        grid-template-columns: 48px minmax(0, 1fr);
    }

    .profile-problem-item .difficulty {
        grid-column: 2;
    }
}

@media (max-width: 360px) {
    .site-brand-main {
        font-size: 24px;
    }

    .nav {
        gap: var(--space-3);
    }

    .auth-area {
        align-items: stretch;
        flex-direction: column;
    }

    .login-button,
    .logout-button,
    .user-link {
        width: 100%;
    }

    .problem-filter-panel,
    .card,
    .problem-card {
        padding: var(--space-3);
    }

    .difficulty-range-header,
    .sample-title-row {
        align-items: flex-start;
        flex-direction: column;
    }

    .profile-stats,
    .profile-result-stats {
        grid-template-columns: 1fr;
    }

    .profile-stat,
    .profile-result-stat {
        border-right: 0;
    }

    .problem-title-main,
    .profile-title,
    .ranking-status-message,
    .judge-error-message,
    .source-code {
        overflow-wrap: anywhere;
    }

    .request-modal-backdrop {
        padding: var(--space-2);
    }
}

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

    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        scroll-behavior: auto !important;
        transition-duration: 0.01ms !important;
    }
}