/* 기본 리셋 및 변수 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #008cff;
    --primary-dark: #0066cc;
    --secondary-color: #00d4ff;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --bg-light: #f9fafb;
    --bg-white: #ffffff;
    --border-color: #e5e7eb;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 25px rgba(0,0,0,0.1);
    --shadow-xl: 0 20px 40px rgba(0,0,0,0.15);
}

body {
    font-family: 'Noto Sans KR', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 네비게이션 */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow-sm);
    z-index: 1000;
    transition: all 0.3s ease;
}

.navbar.scrolled {
    box-shadow: var(--shadow-md);
}

.nav-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 0;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
}

.logo-text {
    font-size: 28px;
    font-weight: 900;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.logo-badge {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 30px;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 500;
    transition: color 0.3s ease;
}

.nav-links a:hover {
    color: var(--primary-color);
}

.btn-login {
    background: transparent;
    border: 2px solid var(--primary-color);
    color: var(--primary-color);
    padding: 10px 24px;
    border-radius: 25px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

.btn-login:hover {
    background: var(--primary-color);
    color: white;
}

/* 히어로 섹션 */
.hero {
    padding: 140px 0 80px;
    background: linear-gradient(135deg, #f0f9ff 0%, #fdf4ff 100%);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 800px;
    height: 800px;
    background: radial-gradient(circle, rgba(99, 102, 241, 0.1) 0%, transparent 70%);
    border-radius: 50%;
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
    position: relative;
    z-index: 1;
    padding: 0 20px;
}

.hero-title {
    font-size: 56px;
    font-weight: 900;
    line-height: 1.2;
    margin-bottom: 24px;
    white-space: nowrap;
}

.highlight {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-description {
    font-size: 20px;
    color: var(--text-secondary);
    margin-bottom: 40px;
    line-height: 1.8;
}

.hero-cta {
    margin-bottom: 50px;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: white;
    border: none;
    padding: 16px 36px;
    border-radius: 30px;
    font-size: 18px;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: var(--shadow-lg);
    display: inline-flex;
    align-items: center;
    gap: 10px;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-xl);
}

.btn-large {
    padding: 20px 40px;
    font-size: 18px;
}

.cta-note {
    margin-top: 16px;
    font-size: 14px;
    color: var(--text-secondary);
}

.hero-stats {
    display: flex;
    gap: 40px;
    justify-content: center;
    flex-wrap: nowrap;
    gap: clamp(10px, 4vw, 40px);
}

.stat-item {
    display: flex;
    text-align: center;
    flex-direction: column;
}

.stat-number {
    font-size: 32px;
    font-weight: 900;
    color: var(--primary-color);
}

.stat-label {
    font-size: 14px;
    color: var(--text-secondary);
}

/* 히어로 비주얼 */
.hero-visual {
    position: relative;
    height: 500px;
}

.visual-card {
    position: absolute;
    background: white;
    padding: 20px 24px;
    border-radius: 16px;
    box-shadow: var(--shadow-lg);
    display: flex;
    align-items: center;
    gap: 16px;
    animation: float 3s ease-in-out infinite;
}

.visual-card i {
    font-size: 32px;
}

.visual-card p {
    font-size: 14px;
    line-height: 1.4;
}

.card-1 {
    top: 20px;
    left: 20px;
    animation-delay: 0s;
}

.card-1 i {
    color: var(--warning-color);
}

.card-2 {
    top: 180px;
    right: 40px;
    animation-delay: 0.5s;
}

.card-2 i {
    color: var(--success-color);
}

.card-3 {
    bottom: 40px;
    left: 60px;
    animation-delay: 1s;
}

.card-3 i {
    color: var(--primary-color);
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-20px); }
}

/* 문제 제기 섹션 */
.problem-section {
    padding: 100px 0;
    background: var(--bg-white);
}

.section-title {
    text-align: center;
    font-size: 42px;
    font-weight: 900;
    margin-bottom: 60px;
}

.problem-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 40px;
}

.problem-card {
    text-align: center;
    padding: 40px 30px;
    background: var(--bg-light);
    border-radius: 20px;
    transition: all 0.3s ease;
}

.problem-card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-lg);
}

.problem-icon {
    font-size: 64px;
    margin-bottom: 24px;
}

.problem-card h3 {
    font-size: 22px;
    font-weight: 700;
    margin-bottom: 16px;
}

.problem-card p {
    color: var(--text-secondary);
    line-height: 1.8;
}

/* 솔루션 섹션 */
.solution-section {
    padding: 100px 0;
    background: linear-gradient(to bottom, var(--bg-light), var(--bg-white));
}

.section-subtitle {
    text-align: center;
    font-size: 18px;
    color: var(--text-secondary);
    margin-top: -40px;
    margin-bottom: 80px;
}

.feature-list {
    display: flex;
    flex-direction: column;
    gap: 120px;
}

.feature-content {
    padding: 0 30px;
}

.feature-item {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 80px;
    align-items: center;
}

.feature-right {
    direction: rtl;
}

.feature-right > * {
    direction: ltr;
}

.feature-badge {
    display: inline-block;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 8px 20px;
    border-radius: 20px;
    font-size: 14px;
    font-weight: 700;
    margin-bottom: 20px;
}

.feature-title {
    font-size: 36px;
    font-weight: 900;
    margin-bottom: 20px;
}

.feature-description {
    font-size: 18px;
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 30px;
}

.feature-benefits {
    list-style: none;
}

.feature-benefits li {
    padding: 12px 0;
    font-size: 16px;
    display: flex;
    align-items: center;
    gap: 12px;
}

.feature-benefits i {
    color: var(--success-color);
    font-size: 18px;
}


/* 목업 카드 */
.mockup-card {
    width: 100%;
    max-width: 400px;
    background: white;
    border-radius: 20px;
    box-shadow: var(--shadow-xl);
    overflow: hidden;
    transition: all 0.3s ease;
}

.mockup-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 25px 50px rgba(0,0,0,0.2);
}

.mockup-header {
    background: linear-gradient(135deg, #f8f9fa, #e9ecef);
    padding: 14px 20px;
    display: flex;
    gap: 8px;
}

.mockup-dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: #ced4da;
}

.mockup-dot:nth-child(1) {
    background: #ff5f56;
}

.mockup-dot:nth-child(2) {
    background: #ffbd2e;
}

.mockup-dot:nth-child(3) {
    background: #27c93f;
}

.mockup-content {
    padding: 30px;
}

.assignment-item {
    padding: 20px;
    background: var(--bg-light);
    border-radius: 12px;
}

.assignment-status {
    display: inline-block;
    background: var(--warning-color);
    color: white;
    padding: 4px 12px;
    border-radius: 12px;
    font-size: 12px;
    font-weight: 700;
    margin-bottom: 12px;
}

.assignment-item h4 {
    font-size: 18px;
    margin-bottom: 8px;
}

.assignment-due {
    color: var(--text-secondary);
    font-size: 14px;
    margin-bottom: 16px;
}

.btn-small {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 10px 20px;
    border-radius: 8px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

.btn-small:hover {
    background: var(--primary-dark);
}

/* 캘린더 목업 */
.calendar-preview {
    padding: 20px;
}

.calendar-header {
    font-size: 20px;
    font-weight: 700;
    text-align: center;
    margin-bottom: 20px;
    padding-bottom: 16px;
    border-bottom: 2px solid var(--border-color);
}

.calendar-events {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.event-item {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 16px;
    background: var(--bg-light);
    border-radius: 12px;
    border-left: 4px solid var(--primary-color);
}

.event-date {
    font-weight: 700;
    color: var(--primary-color);
    font-size: 18px;
}

.event-title {
    font-size: 16px;
}

/* 학습 아이템 */
.study-item {
    padding: 20px;
    background: var(--bg-light);
    border-radius: 12px;
    margin-bottom: 16px;
}

.study-item h4 {
    font-size: 18px;
    margin-bottom: 8px;
}

.study-item p {
    color: var(--text-secondary);
    font-size: 14px;
    margin-bottom: 12px;
}

/* 요금제 섹션 */
.pricing-section {
    padding: 100px 0;
    background: var(--bg-white);
}

.pricing-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 30px;
    margin-top: 60px;
}

.pricing-card {
    background: white;
    border: 2px solid var(--border-color);
    border-radius: 24px;
    padding: 40px 30px;
    text-align: center;
    transition: all 0.3s ease;
    position: relative;
    min-width: 0;
    display: flex;
    flex-direction: column;
}

.pricing-card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-xl);
}

.pricing-card.featured {
    border-color: var(--primary-color);
    border-width: 3px;
    transform: scale(1.05);
}

.pricing-ribbon {
    position: absolute;
    top: 20px;
    right: -10px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 6px 20px;
    font-size: 12px;
    font-weight: 700;
    border-radius: 20px 0 0 20px;
}

.pricing-header {
    margin-top: 6px;
}

.pricing-header h3 {
    font-size: 24px;
    font-weight: 900;
    margin-bottom: 12px;
}

.pricing-price {
    margin-bottom: 30px;
    padding-bottom: 30px;
    border-bottom: 2px solid var(--border-color);
    white-space: nowrap;
    display: flex;
    justify-content: center;
    align-items: baseline;
    gap: 4px;
}

.price-amount {
    font-size: 38px;
    font-weight: 900;
    color: var(--primary-color);
}

.price-period {
    font-size: 16px;
    color: var(--text-secondary);
}

.pricing-features {
    list-style: none;
    margin-bottom: 30px;
    text-align: left;
    flex: 1;
}

.pricing-features li {
    padding: 12px 0;
    font-size: 15px;
    display: flex;
    align-items: flex-start;
    gap: 12px;
    line-height: 1.6;
}

.pricing-features i {
    color: var(--success-color);
    margin-top: 4px;
    flex-shrink: 0;
}

.btn-pricing {
    width: 100%;
    background: white;
    border: 2px solid var(--primary-color);
    color: var(--primary-color);
    padding: 14px 24px;
    border-radius: 12px;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.3s ease;
    margin-bottom: 16px;
}

.btn-pricing:hover {
    background: var(--primary-color);
    color: white;
}

.btn-pricing.primary {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark)) border-box;
    color: white;
    border: 2px solid transparent;
    -webkit-background-clip: padding-box, border-box;
    background-clip: padding-box, border-box;
    background-origin: border-box;
}

.pricing-note {
    font-size: 13px;
    color: var(--text-secondary);
}

/* CTA 섹션 */
.cta-section {
    padding: 100px 0;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    text-align: center;
}

.cta-title {
    font-size: 48px;
    font-weight: 900;
    margin-bottom: 24px;
    line-height: 1.3;
}

.cta-description {
    font-size: 20px;
    margin-bottom: 40px;
    line-height: 1.8;
    opacity: 0.95;
}

.cta-section .btn-primary {
    background: white;
    color: var(--primary-color);
}

.cta-section .btn-primary:hover {
    transform: translateY(-3px);
}

/* About 섹션 */
.about-section {
    padding: 100px 0;
    background: var(--bg-light);
}

.about-content {
    max-width: 900px;
    margin: 0 auto;
    text-align: center;
}

.about-text {
    font-size: 18px;
    line-height: 2;
    color: var(--text-secondary);
    margin-bottom: 30px;
}

.about-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 40px;
    margin-top: 60px;
}

.about-stat-item {
    text-align: center;
}

.about-stat-item i {
    font-size: 48px;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.about-stat-item h3 {
    font-size: 22px;
    font-weight: 700;
    margin-bottom: 12px;
}

.about-stat-item p {
    color: var(--text-secondary);
}

/* Footer */
.footer {
    background: var(--text-primary);
    color: white;
    padding: 60px 0 30px;
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr 3fr;
    gap: 60px;
    margin-bottom: 40px;
}

.footer-brand p {
    color: rgba(255, 255, 255, 0.7);
    margin-top: 12px;
}

.footer-links {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 40px;
}

.footer-column h4 {
    font-size: 18px;
    font-weight: 700;
    margin-bottom: 20px;
}

.footer-column a {
    display: block;
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    margin-bottom: 12px;
    transition: color 0.3s ease;
}

.footer-column a:hover {
    color: white;
}

.footer-column p {
    color: rgba(255, 255, 255, 0.7);
    font-size: 14px;
    margin-bottom: 8px;
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 30px;
    text-align: center;
    color: rgba(255, 255, 255, 0.5);
}

/* 반응형 디자인 */
@media (max-width: 1024px) {
    .pricing-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .pricing-card.featured {
        transform: scale(1);
    }
    
    .hero-title {
        font-size: 52px;
    }
    
    .hero-content {
        padding: 0 20px;
    }
}

@media (max-width: 900px) {
    .visual-card {
        padding: 16px 20px;
    }

    .visual-card i {
        font-size: 28px;
        width: 42px;
    }

    .visual-card p {
        font-size: 13px;
    }

    .visual-card p strong {
        font-size: 14px;
    }
    
    
    .hero-content {
        padding: 0 0px;
    }
}

@media (max-width: 768px) {
    .nav-links {
        display: none;
    }

    .hero-content {
        grid-template-columns: 1fr;
        gap: 40px;
    }
    
    .hero-title {
        font-size: 38px;
    }
    
    .hero-visual {
        position: relative;
        height: auto;
        display: flex;
        flex-direction: column;
        gap: 16px;
    }

    .visual-card {
        position: relative;
        top: auto !important;
        left: auto !important;
        right: auto !important;
        bottom: auto !important;
        animation: none;
        justify-content: center;
        padding: 18px 20px;
        width: 100%;
        max-width: 320px;
        margin: 0 auto;
    }

    .visual-card i {
        font-size: 32px;
        width: 48px;
        flex-shrink: 0;
        text-align: center;
    }

    .visual-card p {
        font-size: 14px;
        flex: 1;
    }

    .visual-card p strong {
        font-size: 15px;
    }
    
    .problem-grid {
        grid-template-columns: 1fr;
    }
    
    .feature-item,
    .feature-right {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .feature-visual {
        display: flex;
        justify-content: center;
    }

    .pricing-grid {
        grid-template-columns: 1fr;
    }
    
    .about-stats {
        grid-template-columns: 1fr;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
    }
    
    .footer-links {
        grid-template-columns: 1fr;
    }
    
    .cta-title {
        font-size: 32px;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 32px;
    }
    
    .hero-description {
        font-size: 16px;
    }

    .section-title {
        font-size: 32px;
    }
    
    .btn-large {
        padding: 16px 28px;
        font-size: 16px;
    }
}