:root {
    --bg-dark: #0b0f19;
    --bg-card: #141b2d;
    --bg-card-hover: #1b253d;
    --accent-cyan: #05ffc5;
    --accent-blue: #00f2fe;
    --accent-purple: #bb86fc;
    --accent-gold: #ffd700;
    --text-light: #f5f7fa;
    --text-muted: #8fa0dd;
    --border-tech: rgba(0, 242, 254, 0.15);
    --border-tech-active: rgba(5, 255, 197, 0.6);
    --transition-smooth: all 0.4s cubic-bezier(0.16, 1, 0.3, 1);
    --radius-lg: 20px;
    --radius-md: 14px;
    --radius-sm: 8px;
    --shadow-glow: 0 0 20px rgba(0, 242, 254, 0.08);
    --shadow-glow-active: 0 0 25px rgba(5, 255, 197, 0.2);
}

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

body {
    font-family: 'Outfit', 'Noto Sans KR', sans-serif;
    background-color: var(--bg-dark);
    color: var(--text-light);
    line-height: 1.65;
    overflow-x: hidden;
}

/* --- Header --- */
header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    padding: 20px 5%;
    background: rgba(11, 15, 25, 0.85);
    backdrop-filter: blur(12px);
    z-index: 100;
    border-bottom: 1px solid rgba(0, 242, 254, 0.08);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.header-logo {
    font-weight: 900;
    font-size: 1.15rem;
    letter-spacing: 2px;
    color: var(--text-light);
    display: flex;
    align-items: center;
    gap: 10px;
}

.header-logo span {
    font-size: 0.72rem;
    background: linear-gradient(135deg, var(--accent-blue), var(--accent-cyan));
    color: var(--bg-dark);
    padding: 2px 8px;
    border-radius: 4px;
    font-weight: 800;
}

.header-links {
    display: flex;
    gap: 12px;
}

.btn-header-link {
    font-size: 0.72rem;
    font-weight: 800;
    text-decoration: none;
    color: var(--text-light);
    padding: 8px 16px;
    border: 1px solid rgba(0, 242, 254, 0.25);
    border-radius: 30px;
    transition: var(--transition-smooth);
    letter-spacing: 1px;
}

.btn-header-link:hover {
    background: rgba(0, 242, 254, 0.05);
    border-color: var(--accent-blue);
    box-shadow: 0 0 10px rgba(0, 242, 254, 0.2);
}

.btn-header-accent {
    background: linear-gradient(135deg, var(--accent-blue), var(--accent-cyan));
    color: var(--bg-dark);
    border-color: transparent;
}

.btn-header-accent:hover {
    transform: translateY(-1px);
    box-shadow: 0 0 15px rgba(5, 255, 197, 0.4);
}

/* --- Container Layout --- */
.wrapper {
    max-width: 1200px;
    margin: 140px auto 80px auto;
    padding: 0 24px;
}

/* --- Project Overview Hero --- */
.project-hero {
    text-align: center;
    margin-bottom: 70px;
    opacity: 0;
    transform: translateY(20px);
    animation: fade-up-in 0.8s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

@keyframes fade-up-in {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.project-category {
    font-size: 0.8rem;
    font-weight: 800;
    color: var(--accent-cyan);
    text-transform: uppercase;
    letter-spacing: 3px;
    margin-bottom: 12px;
}

.project-title {
    font-size: 2.8rem;
    font-weight: 900;
    line-height: 1.2;
    background: linear-gradient(135deg, var(--text-light) 50%, var(--text-muted));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 20px;
}

.project-subtitle {
    font-size: 1.1rem;
    color: var(--text-muted);
    max-width: 750px;
    margin: 0 auto 30px auto;
    font-weight: 400;
}

/* --- Metadata Cards --- */
.meta-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
    background: var(--bg-card);
    border: 1px solid var(--border-tech);
    border-radius: var(--radius-md);
    padding: 24px;
    box-shadow: var(--shadow-glow);
    margin-bottom: 80px;
}

.meta-item {
    text-align: center;
    border-right: 1px solid rgba(0, 242, 254, 0.08);
}

.meta-item:last-child {
    border-right: none;
}

.meta-lbl {
    font-size: 0.72rem;
    font-weight: 800;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 1.5px;
    margin-bottom: 6px;
}

.meta-val {
    font-size: 1.05rem;
    font-weight: 800;
    color: var(--accent-blue);
}

/* --- Section Styling --- */
section {
    margin-bottom: 100px;
}

.section-header {
    margin-bottom: 40px;
}

.section-num {
    font-size: 0.85rem;
    color: var(--accent-cyan);
    font-weight: 800;
    letter-spacing: 2px;
    margin-bottom: 6px;
    display: block;
}

.section-title {
    font-size: 2rem;
    font-weight: 900;
    color: var(--text-light);
    display: flex;
    align-items: center;
    gap: 12px;
}

.section-title i {
    color: var(--accent-blue);
    font-size: 1.6rem;
}

/* --- Segment 1: Tech Introduction --- */
.tech-intro-box {
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    gap: 50px;
    align-items: center;
    background: var(--bg-card);
    border: 1px solid var(--border-tech);
    border-radius: var(--radius-lg);
    padding: 50px;
    box-shadow: var(--shadow-glow);
}

.intro-left h3 {
    font-size: 1.5rem;
    color: var(--accent-blue);
    margin-bottom: 20px;
}

.intro-left p {
    color: var(--text-muted);
    font-size: 1rem;
    margin-bottom: 18px;
}

.intro-left strong {
    color: var(--text-light);
}

.stats-card {
    background: rgba(11, 15, 25, 0.6);
    border: 1px solid var(--border-tech);
    border-radius: var(--radius-md);
    padding: 30px;
    text-align: center;
    box-shadow: inset 0 0 15px rgba(0, 242, 254, 0.05);
}

.sc-icon {
    font-size: 2.2rem;
    color: var(--accent-cyan);
    margin-bottom: 15px;
}

.sc-number {
    font-size: 2.5rem;
    font-weight: 900;
    color: var(--text-light);
    line-height: 1.1;
    margin-bottom: 8px;
}

.sc-lbl {
    font-size: 0.75rem;
    font-weight: 800;
    color: var(--text-muted);
    text-transform: uppercase;
}

/* --- Segment 2: Interactive Flowchart Layout --- */
.flowchart-grid {
    display: grid;
    grid-template-columns: 1.15fr 0.85fr;
    gap: 40px;
    align-items: start;
}

.flowchart-nodes {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.flow-node {
    background: var(--bg-card);
    border: 1px solid var(--border-tech);
    border-radius: var(--radius-md);
    padding: 20px 24px;
    display: flex;
    align-items: center;
    gap: 20px;
    cursor: pointer;
    position: relative;
    transition: var(--transition-smooth);
}

.flow-node:hover {
    background: var(--bg-card-hover);
    transform: translateX(6px);
    border-color: var(--accent-blue);
    box-shadow: var(--shadow-glow);
}

.flow-node.active {
    background: var(--bg-card-hover);
    border-color: var(--accent-cyan);
    box-shadow: var(--shadow-glow-active);
    transform: translateX(12px);
}

.node-icon {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: rgba(0, 242, 254, 0.08);
    border: 1px solid rgba(0, 242, 254, 0.3);
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 1.25rem;
    color: var(--accent-blue);
    transition: var(--transition-smooth);
}

.flow-node.active .node-icon {
    background: var(--accent-cyan);
    color: var(--bg-dark);
    border-color: var(--accent-cyan);
}

.node-details {
    flex: 1;
}

.node-step {
    font-size: 0.68rem;
    font-weight: 900;
    color: var(--accent-cyan);
    letter-spacing: 1px;
    margin-bottom: 2px;
    display: block;
}

.node-details h4 {
    font-size: 1.05rem;
    color: var(--text-light);
    margin-bottom: 2px;
}

.node-details p {
    font-size: 0.85rem;
    color: var(--text-muted);
}

/* Glowing connector arrows */
.node-arrow {
    position: absolute;
    bottom: -22px;
    left: 48px;
    font-size: 1rem;
    color: rgba(0, 242, 254, 0.4);
    pointer-events: none;
    z-index: 2;
    animation: bounce-arrow 1.5s infinite;
}

@keyframes bounce-arrow {

    0%,
    100% {
        transform: translateY(0);
        opacity: 0.4;
    }

    50% {
        transform: translateY(4px);
        opacity: 1;
    }
}

/* Specs Details Panel */
.flowchart-info-panel {
    position: sticky;
    top: 100px;
    background: var(--bg-card);
    border: 1px solid var(--border-tech);
    border-radius: var(--radius-lg);
    padding: 30px;
    min-height: 480px;
    box-shadow: var(--shadow-glow);
    overflow: hidden;
}

.panel-inner {
    position: relative;
    height: 100%;
}

.panel-card {
    display: none;
    opacity: 0;
    transform: translateY(20px);
    transition: var(--transition-smooth);
}

.panel-card.active {
    display: block;
    opacity: 1;
    transform: translateY(0);
}

.panel-badge {
    display: inline-block;
    font-size: 0.68rem;
    font-weight: 800;
    background: rgba(0, 242, 254, 0.1);
    color: var(--accent-blue);
    padding: 4px 10px;
    border-radius: 4px;
    margin-bottom: 15px;
    letter-spacing: 1px;
    border: 1px solid rgba(0, 242, 254, 0.2);
}

.panel-badge.badge-purple {
    background: rgba(187, 134, 252, 0.1);
    color: var(--accent-purple);
    border-color: rgba(187, 134, 252, 0.2);
}

.panel-badge.badge-green {
    background: rgba(5, 255, 197, 0.1);
    color: var(--accent-cyan);
    border-color: rgba(5, 255, 197, 0.2);
}

.panel-badge.badge-gold {
    background: rgba(255, 215, 0, 0.1);
    color: var(--accent-gold);
    border-color: rgba(255, 215, 0, 0.2);
}

.panel-card h3 {
    font-size: 1.4rem;
    color: var(--text-light);
    margin-bottom: 12px;
}

.panel-desc {
    font-size: 0.92rem;
    color: var(--text-muted);
    margin-bottom: 24px;
}

.code-box {
    background: #060913;
    border: 1px solid rgba(255, 255, 255, 0.06);
    border-radius: var(--radius-sm);
    padding: 16px;
    overflow-x: auto;
}

.code-lbl {
    display: block;
    font-size: 0.65rem;
    font-weight: 800;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 8px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
    padding-bottom: 6px;
}

.code-box pre {
    margin: 0;
}

.code-box code {
    font-family: monospace;
    font-size: 0.8rem;
    color: #e2e8f0;
}

/* --- Segment 3: Core Features Breakdown --- */
.tech-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.tech-card {
    background: var(--bg-card);
    border: 1px solid var(--border-tech);
    border-radius: var(--radius-md);
    padding: 30px;
    transition: var(--transition-smooth);
    box-shadow: var(--shadow-glow);
}

.tech-card:hover {
    transform: translateY(-5px);
    background: var(--bg-card-hover);
    border-color: var(--accent-cyan);
}

.tc-icon-wrap {
    width: 50px;
    height: 50px;
    border-radius: 12px;
    background: rgba(0, 242, 254, 0.06);
    border: 1px solid rgba(0, 242, 254, 0.2);
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 1.35rem;
    color: var(--accent-cyan);
    margin-bottom: 20px;
    transition: var(--transition-smooth);
}

.tech-card:hover .tc-icon-wrap {
    background: var(--accent-cyan);
    color: var(--bg-dark);
}

.tech-card h3 {
    font-size: 1.15rem;
    color: var(--text-light);
    margin-bottom: 12px;
}

.tech-card p {
    font-size: 0.88rem;
    color: var(--text-muted);
}

/* --- Segment 4: Developer's Story --- */
.story-container {
    background: linear-gradient(135deg, var(--bg-card), rgba(20, 27, 45, 0.4));
    border: 1px solid var(--border-tech);
    color: var(--text-light);
    border-radius: var(--radius-lg);
    padding: 60px;
    display: grid;
    grid-template-columns: 0.35fr 0.65fr;
    gap: 50px;
    align-items: center;
    box-shadow: var(--shadow-glow);
}

.story-left {
    text-align: center;
    border-right: 1px solid rgba(0, 242, 254, 0.12);
    padding-right: 50px;
}

.story-avatar-wrap {
    width: 100px;
    height: 100px;
    border-radius: 50%;
    background: var(--bg-dark);
    margin: 0 auto 20px auto;
    border: 2px solid var(--accent-cyan);
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 2.5rem;
    color: var(--accent-cyan);
    box-shadow: 0 0 15px rgba(5, 255, 197, 0.2);
}

.story-left h4 {
    font-size: 1.15rem;
    font-weight: 800;
    letter-spacing: 1.5px;
    margin-bottom: 4px;
}

.story-left p {
    font-size: 0.72rem;
    color: var(--accent-blue);
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 2px;
}

.story-right h3 {
    font-size: 1.5rem;
    margin-bottom: 24px;
    line-height: 1.4;
    color: var(--accent-cyan);
}

.story-right p {
    font-size: 0.95rem;
    line-height: 1.7;
    color: var(--text-muted);
    margin-bottom: 16px;
}

.story-right p strong {
    color: var(--text-light);
}

.story-right p:last-child {
    margin-bottom: 0;
}

/* --- Footer CTA --- */
.bottom-cta {
    text-align: center;
    margin-top: 80px;
    border-top: 1px solid rgba(0, 242, 254, 0.08);
    padding-top: 60px;
}

.cta-title {
    font-size: 1.8rem;
    font-weight: 900;
    color: var(--text-light);
    margin-bottom: 8px;
    letter-spacing: 1px;
}

.cta-subtitle {
    font-size: 0.95rem;
    color: var(--text-muted);
    margin-bottom: 30px;
}

.cta-btn-group {
    display: flex;
    justify-content: center;
    gap: 20px;
}

.btn-cta-link {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
    font-weight: 800;
    font-size: 0.95rem;
    padding: 16px 36px;
    border-radius: 40px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.02);
    transition: var(--transition-smooth);
}

.btn-renewal {
    background: linear-gradient(135deg, var(--accent-blue), var(--accent-cyan));
    color: var(--bg-dark);
    border: none;
}

.btn-renewal:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(5, 255, 197, 0.4);
}

/* --- Mobile Responsiveness --- */
@media (max-width: 992px) {
    .wrapper {
        margin-top: 100px;
    }

    .project-title {
        font-size: 2.2rem;
    }

    .meta-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 15px;
    }

    .meta-item {
        border-right: none;
    }

    .meta-item:nth-child(odd) {
        border-right: 1px solid rgba(0, 242, 254, 0.08);
    }

    .tech-intro-box {
        grid-template-columns: 1fr;
        padding: 30px;
        gap: 30px;
    }

    .flowchart-grid {
        grid-template-columns: 1fr;
        gap: 30px;
    }

    .flowchart-info-panel {
        position: relative;
        top: 0;
        min-height: auto;
    }

    .tech-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }

    .story-container {
        grid-template-columns: 1fr;
        padding: 40px;
        gap: 30px;
    }

    .story-left {
        border-right: none;
        padding-right: 0;
        border-bottom: 1px solid rgba(0, 242, 254, 0.12);
        padding-bottom: 30px;
    }
}

/* --- Footer Copyright --- */
footer {
    border-top: 1px solid rgba(0, 242, 254, 0.05);
    background: #060913;
    padding: 30px 24px;
    text-align: center;
    margin-top: 80px;
}

.footer-inner p {
    font-size: 0.75rem;
    color: rgba(143, 160, 221, 0.6);
    letter-spacing: 0.5px;
}