/* Reset and base styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Noto Sans KR', sans-serif;
    line-height: 1.6;
    color: #333;
}

/* Header and Navigation */
header {
    background-color: #fff;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
}

nav ul {
    display: flex;
    justify-content: center;
    list-style: none;
    padding: 1rem;
}

nav ul li {
    margin: 0 1.5rem;
}

nav ul li a {
    text-decoration: none;
    color: #333;
    font-weight: 500;
    transition: color 0.3s ease;
}

nav ul li a:hover {
    color: #007bff;
}

/* Main content */
main {
    margin-top: 60px;
    padding: 2rem;
}

.section {
    max-width: 1200px;
    margin: 0 auto;
    padding: 4rem 2rem;
}

.section h1 {
    text-align: center;
    margin-bottom: 2rem;
    color: #2c3e50;
}

/* Profile section */
.profile-content {
    display: flex;
    align-items: center;
    gap: 2rem;
    flex-wrap: wrap;
}

.profile-image {
    flex: 0 0 300px;
}

.placeholder-image {
    width: 100%;
    height: 300px;
    background-color: #f0f0f0;
    border-radius: 10px;
}

.profile-info {
    flex: 1;
    min-width: 300px;
}

.profile-photo {
    width: 200px;
    height: 200px;
    border-radius: 50%;
    object-fit: cover;
    display: block;
    margin-bottom: 1rem;
}

/* Mobile app section */
.app-content {
    text-align: center;
}

.app-image {
    flex: 1;
    min-width: 300px;
    height: 100%;
    min-height: 560px;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Mobile app section specific styles */
.app-header {
    text-align: center;
    margin-bottom: 3rem;
}

.app-subtitle {
    color: #666;
    font-size: 1.2rem;
    margin-top: 0.5rem;
}

.app-showcase {
    display: flex;
    gap: 3rem;
    align-items: flex-start;
    margin-bottom: 4rem;
    flex-wrap: wrap;
}

.app-description {
    flex: 1;
    min-width: 300px;
    font-size: 1.1rem;
    line-height: 1.8;
}

.app-description-features {
    flex: 1;
    min-width: 320px;
    padding-left: 2rem;
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.app-features {
    margin-bottom: 4rem;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.feature-card {
    background: #fff;
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    transition: transform 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-5px);
}

.feature-card h4 {
    color: #2c3e50;
    margin-bottom: 1rem;
    font-size: 1.2rem;
}

.app-download {
    text-align: center;
    padding: 3rem;
    background: #f8f9fa;
    border-radius: 15px;
}

.download-buttons {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-top: 2rem;
}

.download-button {
    display: inline-flex;
    flex-direction: column;
    align-items: center;
    padding: 1rem 2rem;
    background: #2c3e50;
    color: white;
    text-decoration: none;
    border-radius: 10px;
    transition: background-color 0.3s ease;
}

.download-button:hover {
    background: #34495e;
}

.button-text {
    font-size: 1.2rem;
    font-weight: 500;
}

.button-subtext {
    font-size: 0.9rem;
    opacity: 0.8;
}

/* GPTs section */
.gpts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.gpt-card {
    background: #fff;
    border-radius: 10px;
    padding: 1.5rem;
    text-decoration: none;
    color: inherit;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.gpt-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
}

.gpt-card h3 {
    color: #2c3e50;
    margin-bottom: 1rem;
}

.gpt-thumb {
    width: 100%;
    max-width: 120px;
    height: auto;
    display: block;
    margin: 0 auto 1rem auto;
    border-radius: 12px;
    object-fit: cover;
}

/* Footer */
footer {
    text-align: center;
    padding: 2rem;
    background-color: #f8f9fa;
    margin-top: 4rem;
}

/* Responsive adjustments */
@media (max-width: 768px) {
    nav ul {
        flex-direction: column;
        align-items: center;
    }

    nav ul li {
        margin: 0.5rem 0;
    }

    .profile-content {
        flex-direction: column;
        text-align: center;
    }

    .section {
        padding: 2rem 1rem;
    }

    .app-showcase {
        flex-direction: column;
        align-items: center;
    }

    .app-description-features {
        padding-left: 0;
        width: 100%;
    }

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

    .download-buttons {
        flex-direction: column;
    }

    main {
        margin-top: 100px;
    }
}

@media (max-width: 900px) {
    .app-image {
        min-height: 400px;
    }
}

.youtube-shorts-wrapper {
    position: relative;
    width: 100%;
    max-width: 400px;
    height: 700px;
    margin: 0 auto;
    background: #000;
    border-radius: 16px;
    overflow: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
}
.youtube-shorts-wrapper iframe {
    width: 400px;
    height: 700px;
    border: 0;
    transform: scale(1.35);
}
@media (max-width: 500px) {
    .youtube-shorts-wrapper,
    .youtube-shorts-wrapper iframe {
        width: 100vw;
        height: 60vw;
        min-height: 350px;
        max-width: 100vw;
    }
    .youtube-shorts-wrapper iframe {
        transform: scale(1.1);
    }
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}
.project-card {
    background: #fff;
    border-radius: 12px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.08);
    padding: 2rem 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 1rem;
    transition: transform 0.2s, box-shadow 0.2s;
}
.project-card:hover {
    transform: translateY(-4px) scale(1.02);
    box-shadow: 0 6px 20px rgba(0,0,0,0.13);
}
.project-tags {
    margin-top: 0.5rem;
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}
.project-tags span {
    background: #f1f3f6;
    color: #2c3e50;
    border-radius: 999px;
    padding: 0.3em 1em;
    font-size: 0.95em;
    font-weight: 500;
    box-shadow: 0 1px 2px rgba(0,0,0,0.04);
    margin-bottom: 0.2em;
    display: inline-block;
}

.contact-section {
    max-width: 500px;
    margin: 3rem auto;
    background: #fff;
    border-radius: 16px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.07);
    padding: 2.5rem 2rem;
    text-align: center;
}
.contact-list {
    margin-top: 2rem;
    display: flex;
    flex-direction: column;
    gap: 1.2rem;
}
.contact-item {
    display: flex;
    align-items: center;
    gap: 0.7em;
    font-size: 1.15em;
    justify-content: center;
}
.contact-item i {
    font-size: 1.5em;
    color: #e74c3c;
}
.contact-item a {
    color: #2c3e50;
    text-decoration: none;
    font-weight: 500;
    transition: color 0.2s;
}
.contact-item a:hover {
    color: #007bff;
}

.nav-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 2rem;
    cursor: pointer;
    position: absolute;
    left: 1rem;
    top: 1rem;
    z-index: 1100;
}

@media (max-width: 768px) {
    .nav-toggle {
        display: block;
    }
    nav ul.nav-menu {
        display: none;
        flex-direction: column;
        position: fixed;
        top: 60px;
        left: 0;
        width: 100vw;
        background: #fff;
        box-shadow: 0 2px 10px rgba(0,0,0,0.08);
        z-index: 1050;
        padding: 2rem 0;
        transition: all 0.3s;
    }
    nav ul.nav-menu.open {
        display: flex;
    }
    nav ul li {
        margin: 1.2rem 0;
    }
}

@media (min-width: 769px) {
    .nav-toggle {
        display: none !important;
    }
    nav ul.nav-menu {
        display: flex !important;
        position: static;
        flex-direction: row;
        box-shadow: none;
        padding: 1rem;
        width: auto;
        background: none;
    }
    nav ul li {
        margin: 0 1.5rem;
    }
}