/**
 * @fileoverview 편지지 - 전체 공통 스타일
 * @project 편지지 (빈티지 편지 앨범)
 * @generated 20260526_200000
 *
 * 구성:
 *  1. 디자인 토큰 CSS Variables (:root)
 *  2. CSS Reset
 *  3. 공통 베이스
 *  4. 헤더
 *  5. 편지 카드 (LetterCard) — 기존 유지 (하위 호환)
 *  6. 폴라로이드 카드 — 신규 추가
 *  7. 커버 섹션 — 신규 추가
 *  8. 피드 (Feed) 상태
 *  9. 업로드 폼
 * 10. 버튼
 * 11. 배지 / 스피너 / 토스트 / 라이트박스
 * 12. 로그인 페이지 — 신규 추가
 * 13. 반응형
 */

/* =========================================================================
   1. 디자인 토큰 CSS Variables
   ========================================================================= */

:root {
  /* Color — Primary (Sepia) */
  --color-primary-900: #2C1A0E;
  --color-primary-700: #5C3D1E;
  --color-primary-500: #8B6340;
  --color-primary-300: #C4A882;
  --color-primary-100: #E8D9C4;

  /* Color — Secondary (Ink Blue) */
  --color-secondary-700: #2E4057;
  --color-secondary-400: #6B8CAE;
  --color-secondary-100: #D6E4F0;

  /* Color — Semantic */
  --color-success: #4A7C59;
  --color-warning: #B07D2C;
  --color-error: #8B2E2E;
  --color-info: #2E5C8B;

  /* Color — Background */
  --color-bg-page: #F5F0E8;
  --color-bg-card: #FAF7F2;
  --color-bg-overlay: rgba(44, 26, 14, 0.6);

  /* Color — Text */
  --color-text-primary: #2C1A0E;
  --color-text-secondary: #5C3D1E;
  --color-text-muted: #8B6340;
  --color-text-on-dark: #FAF7F2;

  /* Color — Border */
  --color-border-default: #C4A882;
  --color-border-strong: #8B6340;
  --color-border-focus: #2E4057;

  /* Typography */
  --font-body:    'Nanum Myeongjo', Georgia, serif;
  --font-display: 'Gowun Dodum', 'Apple SD Gothic Neo', sans-serif;
  --font-mono:    'Courier New', Courier, monospace;

  --size-xs:   12px;
  --size-sm:   14px;
  --size-base: 16px;
  --size-md:   18px;
  --size-lg:   20px;
  --size-xl:   24px;
  --size-2xl:  30px;
  --size-3xl:  36px;

  --weight-regular:   400;
  --weight-bold:      700;
  --weight-extrabold: 800;

  --leading-tight:   1.3;
  --leading-normal:  1.6;
  --leading-relaxed: 1.9;

  --tracking-tight:   -0.01em;
  --tracking-normal:  0;
  --tracking-wide:    0.05em;
  --tracking-widest:  0.12em;

  /* Spacing */
  --spacing-1:  4px;
  --spacing-2:  8px;
  --spacing-3:  12px;
  --spacing-4:  16px;
  --spacing-5:  20px;
  --spacing-6:  24px;
  --spacing-8:  32px;
  --spacing-10: 40px;
  --spacing-12: 48px;
  --spacing-16: 64px;

  /* Border Radius */
  --radius-none: 0px;
  --radius-xs:   2px;
  --radius-sm:   4px;
  --radius-md:   8px;
  --radius-lg:   12px;
  --radius-xl:   16px;
  --radius-full: 9999px;

  /* Shadow */
  --shadow-xs:    0 1px 2px rgba(44, 26, 14, 0.08);
  --shadow-sm:    0 2px 6px rgba(44, 26, 14, 0.12);
  --shadow-md:    0 4px 16px rgba(44, 26, 14, 0.16);
  --shadow-lg:    0 8px 32px rgba(44, 26, 14, 0.20);
  --shadow-inset: inset 0 1px 3px rgba(44, 26, 14, 0.10);

  /* Border */
  --border-thin:   1px;
  --border-medium: 2px;

  /* Transition */
  --duration-fast:   150ms;
  --duration-normal: 250ms;
  --duration-slow:   400ms;
  --easing-default:  ease-in-out;
  --easing-bounce:   cubic-bezier(0.34, 1.56, 0.64, 1);

  /* z-index */
  --z-base:    0;
  --z-card:    10;
  --z-sticky:  100;
  --z-overlay: 200;
  --z-modal:   300;
  --z-toast:   400;

  /* Layout */
  --max-width-card: 640px;
  --max-width-feed: 680px;
  --side-padding:   var(--spacing-4);
}

/* =========================================================================
   2. CSS Reset
   ========================================================================= */

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

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  font-size: var(--size-base);
  line-height: var(--leading-normal);
  color: var(--color-text-primary);
  background-color: var(--color-bg-page);
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img {
  display: block;
  max-width: 100%;
  height: auto;
}

a {
  color: var(--color-secondary-700);
  text-decoration: none;
  transition: color var(--duration-fast) var(--easing-default);
}

a:hover {
  color: var(--color-primary-700);
  text-decoration: underline;
}

ul, ol {
  list-style: none;
}

button {
  cursor: pointer;
  font-family: inherit;
  border: none;
  background: none;
}

input,
textarea,
select {
  font-family: inherit;
  font-size: inherit;
}

/* =========================================================================
   3. 공통 베이스
   ========================================================================= */

.page-wrapper {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.container {
  width: 100%;
  max-width: var(--max-width-feed);
  margin: 0 auto;
  padding: 0 var(--side-padding);
}

.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;
}

/* =========================================================================
   4. 헤더
   ========================================================================= */

.site-header {
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  background-color: var(--color-bg-page);
  border-bottom: var(--border-thin) solid var(--color-border-default);
  transition: box-shadow var(--duration-normal) var(--easing-default);
}

.site-header--scrolled {
  box-shadow: var(--shadow-sm);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 56px;
  padding: 0 var(--side-padding);
}

.site-header__logo {
  font-family: var(--font-body);
  font-size: var(--size-xl);
  font-weight: var(--weight-extrabold);
  color: var(--color-primary-900);
  letter-spacing: var(--tracking-tight);
  text-decoration: none;
}

.site-header__logo:hover {
  color: var(--color-primary-700);
  text-decoration: none;
}

.site-header__nav {
  display: flex;
  align-items: center;
  gap: var(--spacing-3);
}

.site-header__nav-link {
  font-family: var(--font-display);
  font-size: var(--size-sm);
  color: var(--color-text-muted);
  padding: var(--spacing-1) var(--spacing-2);
  border-radius: var(--radius-sm);
  letter-spacing: var(--tracking-wide);
  transition: color var(--duration-fast), background-color var(--duration-fast);
}

.site-header__nav-link:hover,
.site-header__nav-link--active {
  color: var(--color-primary-700);
  background-color: var(--color-primary-100);
  text-decoration: none;
}

/* =========================================================================
   5. 편지 카드 (LetterCard) — 기존 유지 (하위 호환)
   ========================================================================= */

.letter-card {
  background-color: var(--color-bg-card);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
  border: var(--border-thin) solid var(--color-border-default);
  transition:
    transform var(--duration-normal) var(--easing-default),
    box-shadow var(--duration-normal) var(--easing-default);
  /* 빈티지 편지 느낌 — 상하 점선 구분 */
  border-top: var(--border-medium) dashed var(--color-border-default);
  border-bottom: var(--border-medium) dashed var(--color-border-default);
  cursor: default;
  position: relative;
}

.letter-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  z-index: var(--z-card);
}

.letter-card:active {
  transform: translateY(0);
  box-shadow: var(--shadow-sm);
}

/* 사진 영역 */
.letter-card__photo-wrap {
  position: relative;
  width: 100%;
  aspect-ratio: 4 / 3;
  background-color: var(--color-primary-100);
  overflow: hidden;
}

.letter-card__photo-skeleton {
  position: absolute;
  inset: 0;
  background: linear-gradient(
    90deg,
    var(--color-primary-100) 25%,
    var(--color-bg-card) 50%,
    var(--color-primary-100) 75%
  );
  background-size: 200% 100%;
  animation: skeleton-shimmer 1.5s infinite;
}

@keyframes skeleton-shimmer {
  0%   { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

.letter-card__photo {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0;
  transition: opacity var(--duration-normal) var(--easing-default);
}

.letter-card__photo--loaded {
  opacity: 1;
}

.letter-card__photo-error {
  position: absolute;
  inset: 0;
  display: none;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-2);
  color: var(--color-text-muted);
  font-family: var(--font-display);
  font-size: var(--size-sm);
}

.letter-card__photo-error-icon {
  font-size: var(--size-2xl);
  opacity: 0.5;
}

/* 카드 본문 */
.letter-card__body {
  padding: var(--spacing-5) var(--spacing-5) var(--spacing-6);
}

.letter-card__date {
  display: block;
  font-family: var(--font-display);
  font-size: var(--size-sm);
  color: var(--color-text-muted);
  letter-spacing: var(--tracking-wide);
  margin-bottom: var(--spacing-3);
}

.letter-card__text {
  font-family: var(--font-body);
  font-size: var(--size-md);
  line-height: var(--leading-relaxed);
  color: var(--color-text-primary);
  letter-spacing: var(--tracking-normal);
  word-break: keep-all;
  overflow-wrap: break-word;
  margin-bottom: var(--spacing-3);
}

/* Featured 변형 (첫 번째 카드) */
.letter-card--featured {
  border-top-color: var(--color-primary-500);
  border-bottom-color: var(--color-primary-500);
}

.letter-card--featured .letter-card__text {
  font-size: var(--size-lg);
}

/* =========================================================================
   6. 폴라로이드 카드 — 신규 추가
   ========================================================================= */

.polaroid {
  background: #fff;
  border-radius: 2px;
  box-shadow: 0 4px 15px rgba(0,0,0,0.12), 0 1px 4px rgba(0,0,0,0.08);
  padding: 12px 12px 20px;
  max-width: 360px;
  width: 100%;
  margin: 0 auto var(--spacing-8);
  transform: rotate(var(--rotate, 0deg));
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  cursor: pointer;
}

.polaroid:hover {
  transform: rotate(0deg) scale(1.02);
  box-shadow: 0 8px 30px rgba(0,0,0,0.2);
}

.polaroid__photo-wrap {
  position: relative;
  aspect-ratio: 3/4;
  overflow: hidden;
  background: #f0f0f0;
  margin-bottom: 12px;
}

.polaroid__photo-wrap img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.polaroid__body {
  padding: 4px 4px 4px;
  position: relative;
  min-height: 60px;
}

.polaroid__text {
  font-family: var(--font-body, 'Nanum Myeongjo', serif);
  font-size: 0.95rem;
  line-height: 1.6;
  color: #333;
  margin: 0 0 8px;
  white-space: pre-wrap;
}

.polaroid__date {
  position: absolute;
  bottom: 0;
  right: 4px;
  font-size: 0.75rem;
  color: #999;
  font-family: var(--font-display);
}

/* =========================================================================
   7. 커버 섹션 — 신규 추가
   ========================================================================= */

.cover-section {
  position: relative;
  height: 60vh;
  min-height: 320px;
  max-height: 640px;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  margin-bottom: var(--spacing-10);
}

.cover-bg {
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, #FFB6C1 0%, #FF69B4 100%);
  background-size: cover;
  background-position: center;
  filter: brightness(0.7);
}

.cover-content {
  position: relative;
  z-index: 1;
  text-align: center;
  color: #fff;
  text-shadow: 0 2px 8px rgba(0,0,0,0.3);
}

.cover-names {
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 5vw, 2.5rem);
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.cover-dday {
  font-family: var(--font-display);
  font-size: clamp(3rem, 12vw, 6rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1;
  margin-bottom: 0.5rem;
}

.cover-start-date {
  font-size: clamp(0.85rem, 2.5vw, 1rem);
  opacity: 0.9;
}

/* =========================================================================
   8. 피드 상태
   ========================================================================= */

.feed {
  padding: var(--spacing-8) 0 var(--spacing-16);
}

.feed__list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-8);
}

/* 로딩 */
.feed__loading {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-4);
  padding: var(--spacing-16) 0;
  color: var(--color-text-muted);
  font-family: var(--font-display);
  font-size: var(--size-sm);
}

/* 빈 상태 */
.feed__empty {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-4);
  padding: var(--spacing-16) var(--spacing-4);
  text-align: center;
}

.feed__empty-icon {
  font-size: 64px;
  opacity: 0.3;
  line-height: 1;
}

.feed__empty-title {
  font-family: var(--font-body);
  font-size: var(--size-xl);
  font-weight: var(--weight-bold);
  color: var(--color-text-secondary);
}

.feed__empty-desc {
  font-family: var(--font-display);
  font-size: var(--size-sm);
  color: var(--color-text-muted);
}

/* 오류 상태 */
.feed__error {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-4);
  padding: var(--spacing-16) var(--spacing-4);
  text-align: center;
}

.feed__error-icon {
  font-size: 48px;
  color: var(--color-error);
  opacity: 0.6;
}

.feed__error-title {
  font-size: var(--size-lg);
  font-weight: var(--weight-bold);
  color: var(--color-text-secondary);
}

.feed__error-desc {
  font-family: var(--font-display);
  font-size: var(--size-sm);
  color: var(--color-text-muted);
  max-width: 300px;
}

/* =========================================================================
   9. 업로드 폼
   ========================================================================= */

.upload-page {
  padding: var(--spacing-8) 0 var(--spacing-16);
}

.upload-page__title {
  font-family: var(--font-body);
  font-size: var(--size-2xl);
  font-weight: var(--weight-extrabold);
  color: var(--color-primary-900);
  letter-spacing: var(--tracking-tight);
  margin-bottom: var(--spacing-8);
}

.upload-section__title {
  font-family: var(--font-body);
  font-size: var(--size-xl);
  font-weight: var(--weight-bold);
  color: var(--color-primary-900);
  letter-spacing: var(--tracking-tight);
  margin-bottom: var(--spacing-6);
}

.upload-form {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-6);
}

/* 드롭존 */
.drop-zone {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-3);
  padding: var(--spacing-10) var(--spacing-4);
  border: var(--border-medium) dashed var(--color-border-default);
  border-radius: var(--radius-lg);
  background-color: var(--color-bg-card);
  cursor: pointer;
  text-align: center;
  transition:
    border-color var(--duration-fast) var(--easing-default),
    background-color var(--duration-fast) var(--easing-default);
}

.drop-zone:hover,
.drop-zone:focus {
  border-color: var(--color-border-strong);
  background-color: var(--color-primary-100);
  outline: none;
}

.drop-zone--dragover {
  border-color: var(--color-secondary-700);
  background-color: var(--color-secondary-100);
}

.drop-zone__icon {
  font-size: 40px;
  opacity: 0.5;
  line-height: 1;
}

.drop-zone__label {
  font-family: var(--font-display);
  font-size: var(--size-base);
  color: var(--color-text-secondary);
}

.drop-zone__hint {
  font-family: var(--font-display);
  font-size: var(--size-sm);
  color: var(--color-text-muted);
}

/* 사진 미리보기 */
.photo-preview {
  display: none;
  flex-direction: column;
  gap: var(--spacing-3);
}

.photo-preview__img {
  width: 100%;
  border-radius: var(--radius-lg);
  border: var(--border-thin) solid var(--color-border-default);
  object-fit: cover;
  max-height: 360px;
}

.photo-preview__info {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--spacing-2);
}

.photo-preview__size {
  font-family: var(--font-display);
  font-size: var(--size-sm);
  color: var(--color-text-muted);
}

/* 폼 필드 */
.form-field {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-2);
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-2);
  margin-bottom: var(--spacing-4);
}

.form-group label {
  font-family: var(--font-display);
  font-size: var(--size-sm);
  font-weight: var(--weight-bold);
  color: var(--color-text-secondary);
  letter-spacing: var(--tracking-wide);
}

.form-hint {
  font-family: var(--font-display);
  font-size: var(--size-xs);
  color: var(--color-text-muted);
}

.form-label {
  font-family: var(--font-display);
  font-size: var(--size-sm);
  font-weight: var(--weight-bold);
  color: var(--color-text-secondary);
  letter-spacing: var(--tracking-wide);
}

.form-label--required::after {
  content: ' *';
  color: var(--color-error);
}

.form-input,
.form-select {
  padding: var(--spacing-3) var(--spacing-4);
  border: var(--border-thin) solid var(--color-border-default);
  border-radius: var(--radius-md);
  background-color: var(--color-bg-card);
  color: var(--color-text-primary);
  font-size: var(--size-base);
  transition:
    border-color var(--duration-fast) var(--easing-default),
    box-shadow var(--duration-fast) var(--easing-default);
}

.form-input:focus,
.form-select:focus {
  outline: none;
  border-color: var(--color-border-focus);
  border-width: var(--border-medium);
  box-shadow: var(--shadow-inset);
}

/* 편지 텍스트에리어 — 손글씨 줄 배경 */
.form-textarea {
  padding: var(--spacing-4);
  border: var(--border-thin) solid var(--color-border-default);
  border-radius: var(--radius-md);
  background-color: var(--color-bg-card);
  color: var(--color-text-primary);
  font-family: var(--font-body);
  font-size: var(--size-md);
  line-height: var(--leading-relaxed);
  letter-spacing: var(--tracking-normal);
  resize: vertical;
  min-height: 120px;
  /* 편지지 줄 배경 */
  background-image: repeating-linear-gradient(
    transparent,
    transparent calc(var(--leading-relaxed) * var(--size-md) - 1px),
    var(--color-primary-100) calc(var(--leading-relaxed) * var(--size-md) - 1px),
    var(--color-primary-100) calc(var(--leading-relaxed) * var(--size-md))
  );
  background-size: 100% calc(var(--leading-relaxed) * var(--size-md));
  transition:
    border-color var(--duration-fast) var(--easing-default),
    box-shadow var(--duration-fast) var(--easing-default);
}

.form-textarea:focus {
  outline: none;
  border-color: var(--color-border-focus);
  border-width: var(--border-medium);
  box-shadow: var(--shadow-inset);
}

.form-textarea:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

/* 글자 수 카운터 */
.char-counter {
  font-family: var(--font-display);
  font-size: var(--size-xs);
  color: var(--color-text-muted);
  text-align: right;
}

.char-counter--over {
  color: var(--color-error);
  font-weight: var(--weight-bold);
}

/* 오류 메시지 */
.form-error {
  display: none;
  font-family: var(--font-display);
  font-size: var(--size-sm);
  color: var(--color-error);
}

/* 진행 상태 */
.upload-progress {
  display: none;
  padding: var(--spacing-3) var(--spacing-4);
  background-color: var(--color-secondary-100);
  border-radius: var(--radius-md);
  font-family: var(--font-display);
  font-size: var(--size-sm);
  color: var(--color-secondary-700);
  text-align: center;
}

/* 인증 필요 메시지 */
.auth-required-msg {
  padding: var(--spacing-6);
  background-color: var(--color-primary-100);
  border-radius: var(--radius-lg);
  text-align: center;
  font-family: var(--font-display);
  font-size: var(--size-sm);
  color: var(--color-text-muted);
}

/* =========================================================================
   10. 버튼
   ========================================================================= */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-2);
  font-family: var(--font-display);
  font-weight: var(--weight-bold);
  letter-spacing: var(--tracking-wide);
  border-radius: var(--radius-sm);
  border: var(--border-thin) solid transparent;
  cursor: pointer;
  transition:
    background-color var(--duration-fast) var(--easing-default),
    box-shadow var(--duration-fast) var(--easing-default),
    transform var(--duration-fast) var(--easing-default),
    opacity var(--duration-fast) var(--easing-default);
  text-decoration: none;
  white-space: nowrap;
}

.btn:focus-visible {
  outline: var(--border-medium) solid var(--color-border-focus);
  outline-offset: 2px;
}

.btn:active {
  transform: scale(0.98);
}

.btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
  pointer-events: none;
}

/* 크기 */
.btn--sm { padding: 8px 12px; font-size: var(--size-sm);  min-height: 32px; }
.btn--md { padding: 10px 20px; font-size: var(--size-base); min-height: 40px; }
.btn--lg { padding: 14px 28px; font-size: var(--size-md);  min-height: 48px; }
.btn--full { width: 100%; }

/* Primary */
.btn--primary {
  background-color: var(--color-primary-700);
  color: var(--color-text-on-dark);
}
.btn--primary:hover {
  background-color: var(--color-primary-900);
  box-shadow: var(--shadow-xs);
  text-decoration: none;
  color: var(--color-text-on-dark);
}

/* Secondary */
.btn--secondary {
  background-color: transparent;
  color: var(--color-primary-700);
  border-color: var(--color-primary-300);
}
.btn--secondary:hover {
  background-color: var(--color-primary-100);
  text-decoration: none;
}

/* Ghost */
.btn--ghost {
  background-color: transparent;
  color: var(--color-primary-500);
}
.btn--ghost:hover {
  background-color: var(--color-primary-100);
  text-decoration: none;
}

/* Danger */
.btn--danger {
  background-color: var(--color-error);
  color: var(--color-text-on-dark);
}
.btn--danger:hover {
  opacity: 0.9;
  text-decoration: none;
}

/* Link */
.btn--link {
  background-color: transparent;
  color: var(--color-secondary-700);
  padding: 0;
  min-height: unset;
}
.btn--link:hover {
  text-decoration: underline;
}

/* =========================================================================
   11. 배지 / 스피너 / 토스트 / 라이트박스
   ========================================================================= */

/* AlbumBadge */
.album-badge {
  display: inline-flex;
  align-items: center;
  padding: var(--spacing-1) var(--spacing-3);
  background-color: var(--color-primary-100);
  color: var(--color-primary-700);
  font-family: var(--font-display);
  font-size: var(--size-xs);
  font-weight: var(--weight-bold);
  letter-spacing: var(--tracking-widest);
  border-radius: var(--radius-xs);
  cursor: pointer;
  transition:
    background-color var(--duration-fast) var(--easing-default);
}

.album-badge:hover { background-color: var(--color-primary-300); }
.album-badge:active { background-color: var(--color-primary-500); color: var(--color-text-on-dark); }

/* LoadingSpinner */
.spinner {
  display: inline-block;
  border-radius: 50%;
  border-style: solid;
  border-color: var(--color-primary-300);
  border-top-color: var(--color-primary-700);
  animation: spin 0.7s linear infinite;
}

.spinner--sm { width: 16px; height: 16px; border-width: 2px; }
.spinner--md { width: 24px; height: 24px; border-width: 3px; }
.spinner--lg { width: 40px; height: 40px; border-width: 4px; }

.spinner--white {
  border-color: rgba(255,255,255,0.3);
  border-top-color: #fff;
}

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

/* Toast */
#toast-container {
  position: fixed;
  bottom: var(--spacing-6);
  right: var(--spacing-4);
  z-index: var(--z-toast);
  display: flex;
  flex-direction: column;
  gap: var(--spacing-2);
  pointer-events: none;
}

.toast {
  display: inline-block;
  padding: var(--spacing-3) var(--spacing-5);
  border-radius: var(--radius-md);
  font-family: var(--font-display);
  font-size: var(--size-sm);
  color: var(--color-text-on-dark);
  box-shadow: var(--shadow-md);
  cursor: pointer;
  pointer-events: all;
  opacity: 0;
  transform: translateY(12px);
  transition:
    opacity var(--duration-normal) var(--easing-default),
    transform var(--duration-normal) var(--easing-default);
  max-width: 320px;
  word-break: keep-all;
}

.toast--visible {
  opacity: 1;
  transform: translateY(0);
}

.toast--leaving {
  opacity: 0;
  transform: translateY(-8px);
}

.toast--success  { background-color: var(--color-success); }
.toast--error    { background-color: var(--color-error); }
.toast--warning  { background-color: var(--color-warning); }
.toast--info     { background-color: var(--color-info); }

/* PAT 모달 */
.modal {
  position: fixed;
  inset: 0;
  z-index: var(--z-modal);
  display: none;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-4);
}

.modal--open {
  display: flex;
}

.modal__overlay {
  position: absolute;
  inset: 0;
  background-color: var(--color-bg-overlay);
}

.modal__box {
  position: relative;
  z-index: 1;
  background-color: var(--color-bg-card);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  padding: var(--spacing-8);
  width: 100%;
  max-width: 440px;
}

.modal__title {
  font-family: var(--font-body);
  font-size: var(--size-xl);
  font-weight: var(--weight-bold);
  color: var(--color-primary-900);
  margin-bottom: var(--spacing-3);
}

.modal__desc {
  font-family: var(--font-display);
  font-size: var(--size-sm);
  color: var(--color-text-muted);
  line-height: var(--leading-normal);
  margin-bottom: var(--spacing-6);
}

.modal__desc a {
  color: var(--color-secondary-700);
  text-decoration: underline;
}

/* Lightbox */
.lightbox {
  position: fixed;
  inset: 0;
  z-index: var(--z-modal);
  display: none;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-4);
}

.lightbox--open {
  display: flex;
}

.lightbox__overlay {
  position: absolute;
  inset: 0;
  background-color: var(--color-bg-overlay);
  cursor: pointer;
}

.lightbox__content {
  position: relative;
  z-index: 1;
  max-width: 90vw;
  max-height: 90vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-3);
  animation: lightbox-open var(--duration-slow) var(--easing-default);
}

@keyframes lightbox-open {
  from { opacity: 0; transform: scale(0.92); }
  to   { opacity: 1; transform: scale(1); }
}

.lightbox__img {
  max-width: 100%;
  max-height: 80vh;
  object-fit: contain;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
}

.lightbox__caption {
  font-family: var(--font-body);
  font-size: var(--size-base);
  color: var(--color-text-on-dark);
  text-align: center;
  max-width: 600px;
  line-height: var(--leading-relaxed);
  text-shadow: 0 1px 2px rgba(0,0,0,0.5);
}

.lightbox__close {
  position: absolute;
  top: -48px;
  right: 0;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  background-color: rgba(255,255,255,0.15);
  color: var(--color-text-on-dark);
  font-size: var(--size-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background-color var(--duration-fast) var(--easing-default);
}

.lightbox__close:hover {
  background-color: rgba(255,255,255,0.3);
}

/* =========================================================================
   12. 로그인 페이지 — 신규 추가
   ========================================================================= */

.login-page {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, #FFB6C1 0%, #FF69B4 50%, #DB7093 100%);
  padding: var(--spacing-6);
}

.login-card {
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(10px);
  border-radius: 24px;
  padding: 3rem 2.5rem;
  max-width: 360px;
  width: 100%;
  text-align: center;
  box-shadow: 0 20px 60px rgba(0,0,0,0.15);
}

.login-card__icon {
  font-size: 3rem;
  margin-bottom: 1rem;
}

.login-card__title {
  font-family: var(--font-display);
  font-size: 1.4rem;
  color: #7B1F3A;
  margin-bottom: 0.5rem;
}

.login-card__subtitle {
  font-size: 0.85rem;
  color: #999;
  margin-bottom: 2rem;
}

.login-card__input {
  width: 100%;
  box-sizing: border-box;
  padding: 0.75rem 1rem;
  border: 2px solid #FFB6C1;
  border-radius: 12px;
  font-size: 1.1rem;
  text-align: center;
  letter-spacing: 0.2em;
  outline: none;
  margin-bottom: 1rem;
  transition: border-color 0.2s;
}

.login-card__input:focus {
  border-color: #FF69B4;
}

.login-card__btn {
  width: 100%;
  padding: 0.85rem;
  background: linear-gradient(135deg, #FF69B4, #DB7093);
  color: #fff;
  border: none;
  border-radius: 12px;
  font-size: 1rem;
  font-family: var(--font-display);
  cursor: pointer;
  transition: opacity 0.2s, transform 0.1s;
}

.login-card__btn:active { transform: scale(0.98); }

.login-card__error {
  color: #e53e3e;
  font-size: 0.85rem;
  margin-top: 0.75rem;
  display: none;
}

@keyframes shake {
  0%,100% { transform: translateX(0); }
  20%,60% { transform: translateX(-8px); }
  40%,80% { transform: translateX(8px); }
}

.shake { animation: shake 0.4s ease; }

/* =========================================================================
   13. 반응형
   ========================================================================= */

@media (min-width: 480px) {
  :root {
    --side-padding: var(--spacing-6);
  }
}

@media (min-width: 768px) {
  :root {
    --side-padding: var(--spacing-8);
  }

  .site-header__inner {
    height: 64px;
  }

  .letter-card__body {
    padding: var(--spacing-6) var(--spacing-8) var(--spacing-8);
  }

  .feed__list {
    gap: var(--spacing-10);
  }

  #toast-container {
    right: var(--spacing-8);
  }
}

@media (min-width: 1024px) {
  :root {
    --side-padding: var(--spacing-12);
  }
}