:root {
    --primary-color: #2563EB;
    /* Royal Blue */
    --secondary-color: #0F172A;
    /* Slate 900 */
    --accent-color: #38BDF8;
    /* Sky Blue */
    --text-color: #334155;
    /* Slate 700 */
    --bg-color: #F8FAFC;
    /* Slate 50 */
    --white: #ffffff;
    --gray-100: #F1F5F9;
    --gray-200: #E2E8F0;
    --transition: all 0.3s ease;
}

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

body {
    font-family: 'Inter', 'Noto Sans KR', sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
    overflow-x: hidden;
}

a {
    text-decoration: none;
    color: inherit;
}

ul {
    list-style: none;
}

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

/* Header */
header {
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
}

header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--secondary-color);
    letter-spacing: -0.5px;
}

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

.nav-links a {
    font-weight: 500;
    font-size: 0.95rem;
    color: var(--secondary-color);
    transition: var(--transition);
}

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

.btn-primary {
    background-color: var(--primary-color);
    color: var(--white) !important;
    padding: 10px 24px;
    border-radius: 6px;
    font-weight: 600;
    transition: var(--transition);
    display: inline-block;
}

.btn-primary:hover {
    background-color: #1d4ed8;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.2);
}

.btn-secondary {
    background-color: transparent;
    color: var(--secondary-color) !important;
    padding: 10px 24px;
    border-radius: 6px;
    font-weight: 600;
    border: 1px solid var(--gray-200);
    transition: var(--transition);
    display: inline-block;
}

.btn-secondary:hover {
    background-color: var(--gray-100);
    border-color: var(--gray-300);
}

/* Hero Section */
#hero {
    padding: 160px 0 100px;
    background: linear-gradient(135deg, #F8FAFC 0%, #E0F2FE 100%);
    text-align: center;
}

.hero-content h1 {
    font-size: 3.5rem;
    line-height: 1.2;
    color: var(--secondary-color);
    margin-bottom: 24px;
    font-weight: 800;
    letter-spacing: -1px;
}

.hero-content p {
    font-size: 1.25rem;
    color: #64748B;
    margin-bottom: 40px;
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
}

.hero-btns {
    display: flex;
    gap: 16px;
    justify-content: center;
}

/* Sections General */
section {
    padding: 100px 0;
}

.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-header h2 {
    font-size: 2.5rem;
    color: var(--secondary-color);
    margin-bottom: 16px;
    font-weight: 700;
}

.section-header p {
    font-size: 1.1rem;
    color: #64748B;
}

/* Services */
.service-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.service-card {
    background: var(--white);
    padding: 40px;
    border-radius: 16px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
    transition: var(--transition);
    border: 1px solid var(--gray-100);
}

.service-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.05);
    border-color: var(--primary-color);
}

.service-card .icon {
    font-size: 3rem;
    margin-bottom: 24px;
}

.service-card h3 {
    font-size: 1.5rem;
    margin-bottom: 16px;
    color: var(--secondary-color);
}

/* Tech Stack */
#tech-stack {
    background-color: var(--white);
}

.tech-category {
    margin-bottom: 40px;
}

.tech-category h3 {
    font-size: 1.25rem;
    color: var(--secondary-color);
    margin-bottom: 20px;
    border-left: 4px solid var(--primary-color);
    padding-left: 12px;
}

.tech-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
    gap: 20px;
}

.tech-item {
    background-color: var(--gray-100);
    border-radius: 12px;
    padding: 20px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 12px;
    transition: var(--transition);
    border: 1px solid transparent;
}

.tech-item:hover {
    background-color: var(--white);
    transform: translateY(-5px);
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    border-color: var(--primary-color);
}

.tech-item i {
    font-size: 3rem;
    transition: var(--transition);
}

.tech-item:hover i {
    transform: scale(1.1);
}

.custom-icon {
    width: 48px;
    height: 48px;
    transition: var(--transition);
}

.tech-item:hover .custom-icon {
    transform: scale(1.1);
}

.tech-item span {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--secondary-color);
    text-align: center;
}

/* Projects Section */
#projects {
    background-color: var(--bg-color);
}

.project-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(500px, 1fr));
    gap: 30px;
}

.project-card {
    background: var(--white);
    border-radius: 16px;
    overflow: hidden;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
    border: 1px solid var(--gray-200);
    transition: var(--transition);
    display: flex;
    flex-direction: column;
}

.project-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
    border-color: var(--primary-color);
}

.project-content {
    padding: 32px;
    display: flex;
    flex-direction: column;
    height: 100%;
}

.project-content h3 {
    font-size: 1.5rem;
    color: var(--secondary-color);
    margin-bottom: 12px;
    font-weight: 700;
}

.project-desc {
    color: #64748B;
    margin-bottom: 24px;
    line-height: 1.6;
}

.project-features {
    list-style: disc;
    padding-left: 20px;
    margin-bottom: 24px;
    color: var(--text-color);
}

.project-features li {
    margin-bottom: 8px;
    font-size: 0.95rem;
}

.project-tech {
    margin-top: auto;
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.project-tech span {
    background-color: var(--gray-100);
    color: var(--secondary-color);
    padding: 4px 12px;
    border-radius: 6px;
    font-size: 0.85rem;
    font-weight: 500;
}

@media (max-width: 768px) {
    .project-grid {
        grid-template-columns: 1fr;
    }
}

/* Experience / Why Us */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
}

.feature-item {
    background: var(--secondary-color);
    color: var(--white);
    padding: 30px;
    border-radius: 12px;
}

.feature-item h4 {
    font-size: 1.2rem;
    margin-bottom: 12px;
    color: var(--accent-color);
}

.feature-item p {
    color: #94A3B8;
    font-size: 0.95rem;
}

/* Contact */
#contact {
    background-color: var(--primary-color);
    color: var(--white);
    text-align: center;
}

.contact-wrapper h2 {
    font-size: 2.5rem;
    margin-bottom: 20px;
}

.contact-wrapper p {
    font-size: 1.2rem;
    margin-bottom: 40px;
    opacity: 0.9;
}

.contact-wrapper .btn-primary.large {
    background-color: var(--white);
    color: var(--primary-color) !important;
    font-size: 1.1rem;
    padding: 16px 40px;
}

.contact-wrapper .btn-primary.large:hover {
    background-color: var(--gray-100);
}

/* Footer */
footer {
    background-color: var(--secondary-color);
    color: #94A3B8;
    padding: 40px 0;
    text-align: center;
}

.footer-logo {
    color: var(--white);
    font-weight: 700;
    font-size: 1.2rem;
    margin-bottom: 10px;
}

.copyright {
    font-size: 0.9rem;
}

.gsi-material-button {
    -moz-user-select: none;
    -webkit-user-select: none;
    -ms-user-select: none;
    -webkit-appearance: none;
    background-color: WHITE;
    background-image: none;
    border: 1px solid #747775;
    -webkit-border-radius: 4px;
    border-radius: 4px;
    -webkit-box-sizing: border-box;
    box-sizing: border-box;
    color: #1f1f1f;
    cursor: pointer;
    font-family: 'Roboto', arial, sans-serif;
    font-size: 14px;
    height: 40px;
    letter-spacing: 0.25px;
    outline: none;
    overflow: hidden;
    padding: 0;
    position: relative;
    text-align: center;
    -webkit-transition: background-color .218s, border-color .218s, box-shadow .218s;
    transition: background-color .218s, border-color .218s, box-shadow .218s;
    vertical-align: middle;
    white-space: nowrap;
    width: 40px;
    max-width: 400px;
    min-width: min-content;
}

.gsi-material-button .gsi-material-button-icon {
    height: 20px;
    margin-right: 12px;
    min-width: 20px;
    width: 20px;
    margin: 0;
    padding: 9px;
}

.gsi-material-button .gsi-material-button-content-wrapper {
    -webkit-align-items: center;
    align-items: center;
    display: flex;
    -webkit-flex-direction: row;
    flex-direction: row;
    -webkit-flex-wrap: nowrap;
    flex-wrap: nowrap;
    height: 100%;
    justify-content: space-between;
    position: relative;
    width: 100%;
}

.gsi-material-button .gsi-material-button-contents {
    -webkit-flex-grow: 1;
    flex-grow: 1;
    font-family: 'Roboto', arial, sans-serif;
    font-weight: 500;
    overflow: hidden;
    text-overflow: ellipsis;
    vertical-align: top;
}

.gsi-material-button .gsi-material-button-state {
    -webkit-transition: opacity .218s;
    transition: opacity .218s;
    bottom: 0;
    left: 0;
    opacity: 0;
    position: absolute;
    right: 0;
    top: 0;
}

.gsi-material-button:disabled {
    cursor: default;
    background-color: #ffffff61;
    border-color: #1f1f1f1f;
}

.gsi-material-button:disabled .gsi-material-button-contents {
    opacity: 38%;
}

.gsi-material-button:disabled .gsi-material-button-icon {
    opacity: 38%;
}

.gsi-material-button:not(:disabled):active .gsi-material-button-state,
.gsi-material-button:not(:disabled):focus .gsi-material-button-state {
    background-color: #303030;
    opacity: 12%;
}

.gsi-material-button:not(:disabled):hover {
    -webkit-box-shadow: 0 1px 2px 0 rgba(60, 64, 67, .30), 0 1px 3px 1px rgba(60, 64, 67, .15);
    box-shadow: 0 1px 2px 0 rgba(60, 64, 67, .30), 0 1px 3px 1px rgba(60, 64, 67, .15);
}

.gsi-material-button:not(:disabled):hover .gsi-material-button-state {
    background-color: #303030;
    opacity: 8%;
}


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

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

    .hero-btns {
        flex-direction: column;
    }

    .section-header h2 {
        font-size: 2rem;
    }
}