:root {
    --primary: #22c55e;
    --primary-light: #f0fdf4;
    --secondary: #10b981;
    --accent: #facc15;
    --text-dark: #1e293b;
    --text-light: #64748b;
    --bg-white: #ffffff;
    --bg-soft: #f8fafc;
    --border: #e2e8f0;
    --white: #ffffff;

    --container-width: 1200px;
    --font-main: 'Noto Sans KR', sans-serif;
    --font-heading: 'Outfit', sans-serif;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-main);
    color: var(--text-dark);
    line-height: 1.6;
    background-color: var(--bg-white);
    overflow-x: hidden;
}

.container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* Typography */
h1,
h2,
h3,
h4 {
    font-family: var(--font-heading);
    font-weight: 700;
    line-height: 1.2;
}

.text-gradient {
    background: linear-gradient(135deg, var(--primary) 0%, #059669 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.lead {
    font-size: 1.25rem;
    color: var(--text-light);
    margin-bottom: 2rem;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: 0.75rem;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.3s ease;
    cursor: pointer;
    border: none;
}

.btn-lg {
    padding: 1rem 2rem;
    font-size: 1.1rem;
}

.btn-primary {
    background: linear-gradient(135deg, #22c55e 0%, #10b981 100%);
    color: var(--white);
    border: none;
}

.btn-primary:hover {
    background: linear-gradient(135deg, #16a34a 0%, #059669 100%);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(34, 197, 94, 0.3);
}

.btn-danger {
    background-color: #dc2626;
    color: var(--white);
}

.btn-danger:hover {
    background-color: #b91c1c;
    transform: translateY(-2px);
}

.btn-outline {
    background-color: transparent;
    border: 2px solid var(--border);
    color: var(--text-dark);
}

.btn-outline:hover {
    background-color: var(--bg-soft);
    border-color: var(--text-light);
}

.btn-white {
    background-color: var(--white);
    color: #10b981;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

.btn-white:hover {
    background-color: #f8fafc;
    transform: translateY(-2px);
    color: #059669;
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

.btn-text {
    color: var(--text-dark);
}

.shadow {
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

.shadow-lg {
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

.shadow-xl {
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
}

/* Header */
header {
    background-color: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(10px);
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 100;
    border-bottom: 1px solid var(--border);
}

nav {
    height: 5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.75rem;
    font-weight: 800;
    font-family: var(--font-heading);
    letter-spacing: -1px;
    color: var(--text-dark);
}

.logo-accent {
    color: var(--primary);
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 2.5rem;
}

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

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

.nav-auth {
    display: flex;
    gap: 1rem;
    align-items: center;
}

/* Hero Section */
.hero {
    padding: 10rem 0 6rem;
    background-color: #f1f5f9;
}

.hero-grid {
    display: grid;
    grid-template-columns: 1.2fr 1fr;
    gap: 4rem;
    align-items: center;
}

.hero-content h1 {
    font-size: 3.5rem;
    margin-bottom: 1.5rem;
    color: var(--text-dark);
    line-height: 1.25;
}

.badge {
    background: linear-gradient(90deg, #dcfce7 0%, #f0fdf4 100%);
    color: #15803d;
    padding: 0.5rem 1rem;
    border-radius: 2rem;
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    display: inline-block;
    border: 1px solid #bbf7d0;
}

.hero-tags {
    font-size: 1.1rem;
    color: var(--text-light);
    margin-bottom: 2rem;
    line-height: 2;
}

.hero-btns {
    display: flex;
    gap: 1.5rem;
}

.hero-visual {
    display: flex;
    justify-content: center;
    align-items: center;
}

.hero-mockup-img {
    max-width: 100%;
    height: auto;
    max-height: 520px;
    object-fit: contain;
    filter: drop-shadow(0 20px 40px rgba(0, 0, 0, 0.15));
    animation: float 6s ease-in-out infinite;
}

@keyframes float {

    0%,
    100% {
        transform: translateY(0);
    }

    50% {
        transform: translateY(-20px);
    }
}

/* Features */
.features {
    padding: 8rem 0;
    background-color: var(--bg-soft);
}

.section-title {
    text-align: center;
    margin-bottom: 5rem;
}

.section-title h2 {
    font-size: 2.5rem;
}

.feature-rows {
    display: flex;
    flex-direction: column;
    gap: 8rem;
}

.feature-row {
    display: flex;
    align-items: center;
    gap: 6rem;
}

.feature-row.reverse {
    flex-direction: row-reverse;
}

.feature-text {
    flex: 1;
}

.feature-visual {
    flex: 1.2;
    border-radius: 1.5rem;
    overflow: hidden;
    position: relative;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.15);
}

.feature-visual img {
    width: 100%;
    height: auto;
    display: block;
}

.feature-icon {
    width: 4rem;
    height: 4rem;
    border-radius: 1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    margin-bottom: 2rem;
}

.bg-blue-light {
    background-color: #dcfce7;
}

.bg-green-light {
    background-color: #dcfce7;
}

.bg-orange-light {
    background-color: #ffedd5;
}

.feature-text h3 {
    font-size: 2.25rem;
    margin-bottom: 1.25rem;
    color: var(--text-dark);
    line-height: 1.3;
}

.feature-text p {
    color: var(--text-light);
    font-size: 1.1rem;
    line-height: 1.8;
    margin-bottom: 2rem;
}

.feature-checklist {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.feature-checklist li {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 1.05rem;
    color: var(--text-dark);
    font-weight: 500;
}

.feature-checklist i {
    color: #22c55e;
    font-size: 1.2rem;
}

/* CTA Section */
.cta-section {
    padding: 4rem 0 8rem;
    background-color: var(--bg-soft);
}

.cta-box {
    background: linear-gradient(135deg, #10b981 0%, #3b82f6 100%);
    padding: 5rem 3rem;
    border-radius: 2rem;
    text-align: center;
    color: var(--white);
    position: relative;
    overflow: hidden;
    box-shadow: 0 25px 50px -12px rgba(16, 185, 129, 0.25);
}

.cta-box::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(255, 255, 255, 0.1) 0%, transparent 60%);
    pointer-events: none;
}

.cta-box h2 {
    font-size: 2.5rem;
    margin-bottom: 1.5rem;
}

.cta-box p {
    font-size: 1.25rem;
    margin-bottom: 3rem;
    opacity: 0.9;
}

/* Footer */
footer {
    background-color: var(--bg-soft);
    padding: 5rem 0 2rem;
    border-top: 1px solid var(--border);
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 4rem;
    margin-bottom: 4rem;
}

.footer-links h4 {
    margin-bottom: 1.5rem;
    font-size: 1.1rem;
}

.footer-links ul {
    list-style: none;
}

.footer-links li {
    margin-bottom: 0.75rem;
}

.footer-links a {
    text-decoration: none;
    color: var(--text-light);
    transition: color 0.3s;
}

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

.footer-bottom {
    text-align: center;
    padding-top: 2.5rem;
    border-top: 1px solid var(--border);
    color: var(--text-light);
    font-size: 0.875rem;
}


/* Modal Base */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(5px);
    z-index: 1000;
    align-items: center;
    justify-content: center;
}

.modal.active {
    display: flex;
}

.modal-content {
    background-color: var(--white);
    width: 90%;
    max-width: 450px;
    border-radius: 2rem;
    position: relative;
    padding: 3rem 2rem 2.5rem;
    animation: modalSlideUp 0.4s ease-out;
}

@keyframes modalSlideUp {
    from {
        transform: translateY(30px);
        opacity: 0;
    }

    to {
        transform: translateY(0);
        opacity: 1;
    }
}

.modal-close {
    position: absolute;
    top: 1.5rem;
    right: 1.5rem;
    font-size: 1.5rem;
    background: none;
    border: none;
    cursor: pointer;
    color: var(--text-light);
}

/* Tabs */
.modal-tabs {
    display: flex;
    gap: 1.5rem;
    margin-bottom: 2rem;
    border-bottom: 1px solid var(--border);
}

.tab-btn {
    background: none;
    border: none;
    font-size: 1.1rem;
    font-weight: 600;
    padding-bottom: 0.75rem;
    color: var(--text-light);
    cursor: pointer;
    position: relative;
}

.tab-btn.active {
    color: var(--primary);
}

.tab-btn.active::after {
    content: '';
    position: absolute;
    bottom: -1px;
    left: 0;
    width: 100%;
    height: 2px;
    background-color: var(--primary);
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

.tab-content h3 {
    margin-bottom: 1.5rem;
}

.tab-desc {
    color: var(--text-light);
    margin-bottom: 1.5rem;
    font-size: 0.95rem;
}

/* Forms */
.form-group {
    margin-bottom: 1.25rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-dark);
}

.form-group input {
    width: 100%;
    padding: 0.875rem 1rem;
    border-radius: 0.75rem;
    border: 1px solid var(--border);
    font-family: inherit;
    transition: border-color 0.3s;
}

.form-group input:focus {
    outline: none;
    border-color: var(--primary);
}

.btn-block {
    width: 100%;
    margin-top: 0.5rem;
}

.divider {
    text-align: center;
    margin: 1.5rem 0;
    position: relative;
}

.divider::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 0;
    width: 100%;
    height: 1px;
    background-color: var(--border);
}

.divider span {
    background-color: var(--white);
    padding: 0 1rem;
    color: var(--text-light);
    font-size: 0.85rem;
    position: relative;
}

/* Button States */
.btn:disabled,
.btn.disabled {
    opacity: 0.5;
    cursor: not-allowed !important;
    pointer-events: none;
    filter: grayscale(0.5);
}

.btn-google {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
}

.student-tip {
    margin-top: 1.5rem;
    font-size: 0.85rem;
    color: var(--text-light);
    background-color: var(--bg-soft);
    padding: 1rem;
    border-radius: 0.75rem;
}

/* Terms and Conditions */
.terms-group {
    margin: 1.5rem 0;
    padding: 1rem;
    background-color: var(--bg-soft);
    border-radius: 1rem;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.checkbox-item {
    display: flex;
    align-items: flex-start;
    gap: 0.75rem;
    font-size: 0.9rem;
    color: var(--text-dark);
    cursor: pointer;
}

.checkbox-item input[type="checkbox"] {
    width: 1.2rem;
    height: 1.2rem;
    margin-top: 0.1rem;
    cursor: pointer;
}

.checkbox-item label {
    cursor: pointer;
    line-height: 1.4;
}

.checkbox-item a {
    color: var(--primary);
    text-decoration: underline;
}

.checkbox-item.all-check {
    padding-bottom: 0.75rem;
    border-bottom: 1px solid var(--border);
    margin-bottom: 0.25rem;
    font-weight: 600;
}

/* Responsive */
@media (max-width: 968px) {
    .hero-grid {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero-content h1 {
        font-size: 2.5rem;
    }

    .hero-btns {
        justify-content: center;
    }

    .hero-mockup-img {
        max-height: 300px;
    }

    .feature-row,
    .feature-row.reverse {
        flex-direction: column;
        gap: 3rem;
        text-align: center;
    }

    .feature-checklist {
        align-items: center;
    }

    .feature-icon {
        margin: 0 auto 1.5rem auto;
    }

    .nav-links {
        display: none;
    }

    .footer-grid {
        grid-template-columns: 1fr 1fr;
    }
}