/* ====================================
   DA.UM 학생 포털 - 반응형 & UX 개선 CSS
   ==================================== */

/* ====================================
   1. 기본 Reset & 타이포그래피
   ==================================== */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Apple SD Gothic Neo", "Noto Sans KR", sans-serif;
    line-height: 1.6;
    color: #1f2937;
    background-color: #f3f4f6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ====================================
   2. 컨테이너 & 레이아웃
   ==================================== */
.container,
.main-content {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 16px;
}

@media (min-width: 768px) {
    .container,
    .main-content {
        padding: 24px;
    }
}

@media (min-width: 1024px) {
    .container,
    .main-content {
        padding: 32px;
    }
}

/* ====================================
   3. 카드 그리드 시스템
   ==================================== */
.stats-grid,
.subject-grid {
    display: grid;
    gap: 16px;
    grid-template-columns: 1fr;
}

/* 통계 그리드 - 반응형 */
@media (min-width: 640px) {
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .stats-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

/* 과목 그리드 - 반응형 */
@media (min-width: 640px) {
    .subject-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

@media (min-width: 1024px) {
    .subject-grid {
        grid-template-columns: repeat(5, 1fr);
    }
}

/* ====================================
   4. 카드 스타일
   ==================================== */
.card,
.stat-card,
.subject-card,
.cute-card {
    padding: 20px;
    border-radius: 12px;
    background: white;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
}

.card:hover,
.stat-card:hover,
.subject-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

/* 모바일에서 패딩 축소 */
@media (max-width: 767px) {
    .card,
    .stat-card,
    .subject-card,
    .cute-card {
        padding: 16px;
    }
}

/* ====================================
   5. 인터랙티브 요소 (버튼, 입력)
   ==================================== */
button,
.btn,
.button {
    min-height: 44px;
    min-width: 44px;
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    touch-action: manipulation;
}

button:hover,
.btn:hover,
.button:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.15);
}

button:active,
.btn:active,
.button:active {
    transform: translateY(0);
}

/* 모바일에서 버튼 full-width */
@media (max-width: 767px) {
    .mobile-full-btn {
        width: 100%;
    }
}

/* ====================================
   6. 타이포그래피
   ==================================== */
h1 {
    font-size: clamp(24px, 5vw, 32px);
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 16px;
}

h2 {
    font-size: clamp(20px, 4vw, 28px);
    font-weight: 600;
    line-height: 1.3;
    margin-bottom: 12px;
}

h3 {
    font-size: clamp(18px, 3vw, 24px);
    font-weight: 600;
    line-height: 1.4;
    margin-bottom: 8px;
}

p {
    font-size: clamp(14px, 2vw, 16px);
    line-height: 1.6;
}

/* ====================================
   7. 네비게이션 탭
   ==================================== */
.nav-tabs {
    display: flex;
    gap: 8px;
    overflow-x: auto;
    scrollbar-width: none;
    -ms-overflow-style: none;
    padding-bottom: 8px;
}

.nav-tabs::-webkit-scrollbar {
    display: none;
}

.nav-tabs button {
    flex-shrink: 0;
    min-width: 120px;
    padding: 12px 16px;
    white-space: nowrap;
}

.nav-tabs button.tab-active {
    background: white;
    color: #8b5cf6;
    box-shadow: 0 2px 8px rgba(139, 92, 246, 0.3);
}

@media (min-width: 768px) {
    .nav-tabs {
        flex-wrap: wrap;
        justify-content: center;
    }
    
    .nav-tabs button {
        flex: 1 1 auto;
        min-width: 140px;
    }
}

/* ====================================
   8. 반응형 테이블
   ==================================== */
.table-wrapper {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

table {
    width: 100%;
    border-collapse: collapse;
    font-size: 14px;
}

@media (max-width: 767px) {
    table {
        font-size: 12px;
    }
    
    th, td {
        padding: 8px 4px;
    }
}

/* ====================================
   9. 입력 필드
   ==================================== */
input[type="text"],
input[type="number"],
input[type="email"],
input[type="password"],
textarea,
select {
    width: 100%;
    min-height: 44px;
    padding: 12px;
    border: 1px solid #d1d5db;
    border-radius: 8px;
    font-size: 16px;
    transition: border-color 0.3s ease;
}

input:focus,
textarea:focus,
select:focus {
    outline: none;
    border-color: #8b5cf6;
    box-shadow: 0 0 0 3px rgba(139, 92, 246, 0.1);
}

/* iOS에서 input zoom 방지 */
@media (max-width: 767px) {
    input[type="text"],
    input[type="number"],
    input[type="email"],
    input[type="password"],
    textarea,
    select {
        font-size: 16px;
    }
}

/* ====================================
   10. 모달
   ==================================== */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: 16px;
}

.modal-content {
    background: white;
    border-radius: 16px;
    width: 100%;
    max-width: 600px;
    max-height: 90vh;
    overflow-y: auto;
    padding: 24px;
}

@media (max-width: 767px) {
    .modal-content {
        max-height: 95vh;
        padding: 20px;
    }
}

/* ====================================
   11. 스크롤 Top 버튼
   ==================================== */
.scroll-to-top {
    position: fixed;
    bottom: 24px;
    right: 24px;
    width: 56px;
    height: 56px;
    border-radius: 50%;
    background: #8b5cf6;
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 12px rgba(139, 92, 246, 0.3);
    cursor: pointer;
    z-index: 999;
    transition: all 0.3s ease;
}

.scroll-to-top:hover {
    transform: translateY(-4px);
    box-shadow: 0 6px 16px rgba(139, 92, 246, 0.4);
}

@media (max-width: 767px) {
    .scroll-to-top {
        width: 48px;
        height: 48px;
        bottom: 16px;
        right: 16px;
    }
}

/* ====================================
   12. 로딩 & 토스트
   ==================================== */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(255, 255, 255, 0.9);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
}

.spinner {
    width: 48px;
    height: 48px;
    border: 4px solid #e5e7eb;
    border-top-color: #8b5cf6;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

.toast {
    position: fixed;
    bottom: 24px;
    left: 50%;
    transform: translateX(-50%);
    background: #1f2937;
    color: white;
    padding: 12px 24px;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
    z-index: 9999;
    animation: slideUp 0.3s ease;
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateX(-50%) translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateX(-50%) translateY(0);
    }
}

/* ====================================
   13. 스켈레톤 로더
   ==================================== */
.skeleton {
    background: linear-gradient(90deg, #f3f4f6 25%, #e5e7eb 50%, #f3f4f6 75%);
    background-size: 200% 100%;
    animation: loading 1.5s ease-in-out infinite;
}

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

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

*:focus-visible {
    outline: 2px solid #8b5cf6;
    outline-offset: 2px;
}

/* ====================================
   15. 인쇄 스타일
   ==================================== */
@media print {
    .nav-tabs,
    .scroll-to-top,
    button:not(.print-keep) {
        display: none !important;
    }
    
    .card,
    .stat-card {
        break-inside: avoid;
        border: 1px solid #ddd;
    }
}

/* ====================================
   16. 다크모드 준비 (선택사항)
   ==================================== */
@media (prefers-color-scheme: dark) {
    :root {
        --bg-primary: #1f2937;
        --bg-secondary: #111827;
        --text-primary: #f9fafb;
        --text-secondary: #d1d5db;
    }
    
    /* 다크모드 활성화 시 주석 해제
    body {
        background-color: var(--bg-primary);
        color: var(--text-primary);
    }
    
    .card,
    .cute-card {
        background: var(--bg-secondary);
    }
    */
}

/* ====================================
   17. 모션 감소 (접근성)
   ==================================== */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* ====================================
   18. 유틸리티 클래스
   ==================================== */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mt-1 { margin-top: 0.25rem; }
.mt-2 { margin-top: 0.5rem; }
.mt-3 { margin-top: 0.75rem; }
.mt-4 { margin-top: 1rem; }

.mb-1 { margin-bottom: 0.25rem; }
.mb-2 { margin-bottom: 0.5rem; }
.mb-3 { margin-bottom: 0.75rem; }
.mb-4 { margin-bottom: 1rem; }

.p-1 { padding: 0.25rem; }
.p-2 { padding: 0.5rem; }
.p-3 { padding: 0.75rem; }
.p-4 { padding: 1rem; }

.flex { display: flex; }
.flex-col { flex-direction: column; }
.items-center { align-items: center; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }

.gap-1 { gap: 0.25rem; }
.gap-2 { gap: 0.5rem; }
.gap-3 { gap: 0.75rem; }
.gap-4 { gap: 1rem; }

.w-full { width: 100%; }
.h-full { height: 100%; }

.hidden { display: none !important; }
.block { display: block !important; }

/* 반응형 유틸리티 */
@media (min-width: 768px) {
    .md\:flex { display: flex; }
    .md\:hidden { display: none; }
    .md\:block { display: block; }
}

/* ====================================
   19. 학습 중 배지 (펄스 애니메이션)
   ==================================== */
.studying-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 16px;
    background: linear-gradient(135deg, #f59e0b 0%, #ef4444 100%);
    color: white;
    border-radius: 20px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    animation: pulse 2s ease-in-out infinite;
}

.studying-badge:hover {
    transform: scale(1.05);
    box-shadow: 0 4px 12px rgba(245, 158, 11, 0.4);
}

@keyframes pulse {
    0%, 100% {
        box-shadow: 0 0 0 0 rgba(245, 158, 11, 0.7);
    }
    50% {
        box-shadow: 0 0 0 8px rgba(245, 158, 11, 0);
    }
}

/* ====================================
   20. 과목별 색상 (일관성)
   ==================================== */
.subject-korean { background: linear-gradient(135deg, #fecaca 0%, #fca5a5 100%); }
.subject-english { background: linear-gradient(135deg, #bfdbfe 0%, #93c5fd 100%); }
.subject-math { background: linear-gradient(135deg, #a7f3d0 0%, #6ee7b7 100%); }
.subject-science { background: linear-gradient(135deg, #ddd6fe 0%, #c4b5fd 100%); }
.subject-social { background: linear-gradient(135deg, #fde68a 0%, #fcd34d 100%); }
.subject-other { background: linear-gradient(135deg, #e5e7eb 0%, #d1d5db 100%); }

/* ====================================
   21. 진행률 바 (공통)
   ==================================== */
.progress-bar-container {
    width: 100%;
    height: 12px;
    background: #e5e7eb;
    border-radius: 6px;
    overflow: hidden;
}

.progress-bar {
    height: 100%;
    background: linear-gradient(90deg, #8b5cf6 0%, #a78bfa 100%);
    transition: width 0.3s ease;
}

/* ====================================
   22. 완료! ✨
   ==================================== */