/* 메인 스타일 리뉴얼 - 시니어/모던/고대비 */
:root {
    --primary-color: #1976d2;
    --secondary-color: #43a047;
    --accent-color: #ff9800;
    --success-color: #43a047;
    --error-color: #e53935;
    --light-color: #f7fafd;
    --dark-color: #222;
    --text-color: #222;
    --border-radius: 22px;
    --box-shadow: 0 8px 32px rgba(25, 118, 210, 0.10);
    --transition: all 0.25s cubic-bezier(.4,2,.3,1);
}

/* 기본 스타일 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Noto Sans KR', 'Pretendard', sans-serif;
    color: var(--text-color);
    line-height: 1.7;
    background: #f7fafd;
    font-size: 1.18rem;
    min-height: 100vh;
}

a {
    text-decoration: none;
    color: var(--primary-color);
    transition: var(--transition);
}

ul, ol {
    list-style-position: inside;
    margin: 1rem 0;
}

li {
    margin-bottom: 0.5rem;
    font-size: 1.1rem;
}

/* 학습 메인 페이지 스타일 */
.learning-main {
    padding: 3.5rem 0 2.5rem 0;
    min-height: calc(100vh - 180px);
    background: none;
}

/* 컨테이너 */
.container {
    max-width: 1320px;
    margin: 0 auto;
    padding: 2.5rem 1.5rem;
}

/* 페이지 헤더 */
.page-header {
    text-align: center;
    margin-bottom: 3.5rem;
}

.title {
    font-size: 3.1rem;
    color: var(--primary-color);
    margin-bottom: 0.7rem;
    font-weight: 900;
    letter-spacing: -1px;
    text-shadow: 0 2px 12px #1976d222;
}

.subtitle {
    font-size: 1.3rem;
    color: #444;
    max-width: 900px;
    margin: 0 auto 2.2rem;
    line-height: 1.8;
    font-weight: 500;
}

/* 버튼 스타일 */
.btn-primary, .btn-secondary {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.8rem 1.5rem;
    border-radius: var(--border-radius);
    font-weight: 700;
    font-size: 1.1rem;
    transition: var(--transition);
    cursor: pointer;
    text-align: center;
    border: none;
}

.btn-primary {
    background: var(--primary-color);
    color: #fff;
    border-radius: 30px;
    font-size: 1.22rem;
    font-weight: 800;
    padding: 1.1rem 2.5rem;
    box-shadow: 0 2px 12px #1976d233;
    border: none;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    gap: 0.7rem;
    letter-spacing: 0.5px;
}

.btn-primary i {
    font-size: 1.3em;
}

.btn-primary:hover, .btn-primary:focus {
    background: #0d47a1;
    color: #fff;
    transform: translateY(-3px) scale(1.05);
    box-shadow: 0 8px 24px #1976d233;
}

.btn-secondary {
    background-color: #f1f3f4;
    color: var(--text-color);
    border: 2px solid #dadce0;
}

.btn-secondary:hover {
    background-color: #e8eaed;
    transform: translateY(-3px);
}

.btn-primary:disabled, .btn-secondary:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

/* 학습 카드 그리드 */
.learning-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
    gap: 2.5rem;
    margin-bottom: 3.5rem;
}

/* 기존 카드 컨테이너와의 호환성 유지 */
.card-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.learning-card {
    background: #fff;
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: 0 8px 32px #1976d222, 0 1.5px 8px #fff8;
    transition: var(--transition);
    display: flex;
    flex-direction: column;
    border: none;
    min-height: 360px;
    position: relative;
    backdrop-filter: blur(2.5px);
    border-top: 6px solid var(--primary-color);
}
.learning-card:nth-child(2n) { border-top-color: var(--secondary-color); }
.learning-card:nth-child(3n) { border-top-color: var(--accent-color); }
.learning-card:nth-child(4n) { border-top-color: var(--error-color); }

.learning-card:hover {
    transform: translateY(-12px) scale(1.035);
    box-shadow: 0 24px 48px #1976d233, 0 2px 12px #fff8;
    background: #f7fafd;
}

.card-icon {
    height: 140px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: #f0f4fa;
    color: var(--primary-color);
    transition: var(--transition);
    border-bottom: 1.5px solid #e3eafc;
}
.learning-card:nth-child(2n) .card-icon { color: var(--secondary-color); }
.learning-card:nth-child(3n) .card-icon { color: var(--accent-color); }
.learning-card:nth-child(4n) .card-icon { color: var(--error-color); }

.card-icon i {
    font-size: 4.2rem;
    filter: drop-shadow(0 2px 12px #1976d244);
}

.card-content {
    padding: 2.2rem 1.7rem 1.5rem 1.7rem;
    flex-grow: 1;
    display: flex;
    flex-direction: column;
}

.learning-card h2 {
    font-size: 1.55rem;
    margin-bottom: 1.1rem;
    color: var(--primary-color);
    font-weight: 900;
    letter-spacing: -0.5px;
}
.learning-card:nth-child(2n) h2 { color: var(--secondary-color); }
.learning-card:nth-child(3n) h2 { color: var(--accent-color); }
.learning-card:nth-child(4n) h2 { color: var(--error-color); }

.learning-card p {
    margin-bottom: 1.1rem;
    font-size: 1.15rem;
    line-height: 1.7;
    color: #333;
    font-weight: 500;
}

.card-actions {
    margin-top: auto;
    display: flex;
    justify-content: flex-end;
}

.difficulty {
    font-size: 1.13rem;
    margin-bottom: 0.5rem;
    font-weight: 700;
}
.difficulty span {
    font-weight: 800;
    padding: 0.25em 1em;
    border-radius: 14px;
    font-size: 1em;
    margin-left: 0.5em;
    letter-spacing: 0.5px;
    box-shadow: 0 1px 4px #1976d211;
}
.easy {
    background: #e3fcec;
    color: #388e3c;
    border: 1.5px solid #43a047;
}
.medium {
    background: #fffde7;
    color: #f9a825;
    border: 1.5px solid #ffb300;
}
.hard {
    background: #ffebee;
    color: #e53935;
    border: 1.5px solid #e53935;
}

/* 섹션 타이틀 스타일 */
.section-title {
    font-size: 1.7rem;
    color: var(--primary-color);
    font-weight: 900;
    margin-bottom: 1.7rem;
    display: flex;
    align-items: center;
    gap: 0.7rem;
    letter-spacing: -0.5px;
}

/* 인지훈련 효과 섹션 */
.benefits-section {
    background: #e3f2fd;
    border-radius: var(--border-radius);
    padding: 2.7rem 1.7rem 2.2rem 1.7rem;
    margin-bottom: 2.7rem;
    box-shadow: 0 2px 12px #1976d233;
    border: none;
}

.benefits-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 2.2rem;
}

.benefit-item {
    background: #fff;
    border-radius: 20px;
    box-shadow: 0 2px 8px #1976d233;
    padding: 2.2rem 1.3rem 1.3rem 1.3rem;
    text-align: center;
    transition: var(--transition);
    border: none;
    position: relative;
    min-height: 220px;
}

.benefit-item:hover {
    box-shadow: 0 8px 24px #1976d233;
    transform: scale(1.045);
    background: #f7fafd;
}

.benefit-icon {
    width: 70px;
    height: 70px;
    margin: 0 auto 1.1rem auto;
    background: #1976d2;
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2.5rem;
    box-shadow: 0 2px 8px #1976d233;
}

.benefit-item h3 {
    font-size: 1.22rem;
    color: #1976d2;
    font-weight: 800;
    margin-bottom: 0.7rem;
}

.benefit-item p {
    color: #333;
    font-size: 1.09rem;
    margin-bottom: 0.2rem;
    font-weight: 500;
}

/* 기존 정보 섹션 스타일 개선 */
.info-section {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.info-card {
    background-color: white;
    border-radius: var(--border-radius);
    padding: 1.8rem;
    box-shadow: var(--box-shadow);
    transition: var(--transition);
    border-left: 5px solid var(--primary-color);
}

.info-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.15);
}

.info-card h3 {
    font-size: 1.3rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
    border-bottom: 1px solid var(--light-color);
    padding-bottom: 0.5rem;
}

.info-card ul {
    padding-left: 1rem;
}

.info-card li {
    margin-bottom: 0.8rem;
    color: var(--text-color);
    font-size: 1.05rem;
}

.info-card p {
    color: var(--text-color);
    line-height: 1.6;
    font-size: 1.05rem;
}

/* 도움말 섹션 */
.help-section {
    background: #fffde7;
    border-radius: var(--border-radius);
    padding: 2.4rem 1.7rem 1.7rem 1.7rem;
    margin-bottom: 2.7rem;
    box-shadow: 0 2px 12px #ffb30022;
    border: none;
}

.help-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 2.2rem;
}

.help-item {
    background: #fff;
    border-radius: 20px;
    box-shadow: 0 2px 8px #ffb30022;
    padding: 2.2rem 1.3rem 1.3rem 1.3rem;
    transition: var(--transition);
    border: none;
    min-height: 180px;
}

.help-item h3 {
    font-size: 1.15rem;
    color: #f9a825;
    font-weight: 800;
    margin-bottom: 0.7rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.help-item p {
    color: #333;
    font-size: 1.07rem;
    margin-bottom: 0.2rem;
    font-weight: 500;
}

/* 반응형 스타일 */
@media (max-width: 900px) {
    .container {
        padding: 1.2rem 0.2rem;
    }
    .learning-grid {
        gap: 1.2rem;
    }
    .benefits-section, .help-section {
        padding: 1.2rem 0.5rem 1rem 0.5rem;
    }
}

@media (max-width: 768px) {
    .title {
        font-size: 1.5rem;
    }
    .learning-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    .learning-card {
        min-height: 220px;
    }
    .card-content {
        padding: 1.2rem 0.7rem 0.7rem 0.7rem;
    }
    .benefits-grid, .help-content {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
}

/* 접근성 개선 */
@media (prefers-reduced-motion: reduce) {
    * {
        transition: none !important;
        animation: none !important;
    }
}

/* 고대비 모드 */
@media (prefers-contrast: high) {
    :root {
        --primary-color: #0047b3;
        --secondary-color: #006400;
        --accent-color: #b30000;
        --text-color: #000000;
    }
    
    body {
        background-color: white;
    }
    
    .btn-primary {
        border: 2px solid black;
    }
}

/* 공통 컴포넌트 스타일 */
.loading-spinner {
    display: flex;
    justify-content: center;
    align-items: center;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(255, 255, 255, 0.8);
    z-index: 1000;
}

.spinner {
    border: 5px solid #f3f3f3;
    border-top: 5px solid var(--primary-color);
    border-radius: 50%;
    width: 50px;
    height: 50px;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.error-message {
    position: fixed;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    background-color: #f8d7da;
    color: #721c24;
    padding: 10px 20px;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    z-index: 1000;
}

.success-message {
    position: fixed;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    background-color: #d4edda;
    color: #155724;
    padding: 10px 20px;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    z-index: 1000;
}

/* 페이지 이동 버튼 */
.page-navigation {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.nav-btn {
    display: inline-flex;
    align-items: center;
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 0.8rem 1.5rem;
    border-radius: var(--border-radius);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    box-shadow: var(--box-shadow);
}

.nav-btn:hover {
    background-color: #3367d6;
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
    color: white;
}

.nav-btn i {
    margin-right: 0.5rem;
    font-size: 1.1rem;
}

@media (max-width: 768px) {
    .page-navigation {
        flex-direction: column;
        align-items: center;
    }
    
    .nav-btn {
        width: auto;
        min-width: 120px;
        max-width: 80%;
        justify-content: center;
    }
}