/* ===================================
   CSS CUSTOM PROPERTIES
   =================================== */
:root {
    /* Dark Theme (Default) */
    --bg-primary: #0a0a0b;
    --bg-secondary: #111113;
    --bg-tertiary: #1a1a1f;
    --bg-card: #141418;
    --bg-card-hover: #1a1a20;
    --bg-code: #0d1117;

    --text-primary: #e4e4e7;
    --text-secondary: #a1a1aa;
    --text-tertiary: #71717a;
    --text-muted: #52525b;

    --accent: #3b82f6;
    --accent-hover: #2563eb;
    --accent-subtle: rgba(59, 130, 246, 0.1);
    --accent-border: rgba(59, 130, 246, 0.2);

    --border: #27272a;
    --border-light: #1e1e22;

    --code-keyword: #ff7b72;
    --code-string: #a5d6ff;
    --code-class: #79c0ff;
    --code-method: #d2a8ff;
    --code-comment: #8b949e;

    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.5);

    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;

    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

    --nav-height: 72px;
    --container-max: 1120px;
}

/* Light Theme */
[data-theme="light"] {
    --bg-primary: #fafafa;
    --bg-secondary: #f4f4f5;
    --bg-tertiary: #e4e4e7;
    --bg-card: #ffffff;
    --bg-card-hover: #f9f9fb;
    --bg-code: #f6f8fa;

    --text-primary: #18181b;
    --text-secondary: #52525b;
    --text-tertiary: #71717a;
    --text-muted: #a1a1aa;

    --accent: #2563eb;
    --accent-hover: #1d4ed8;
    --accent-subtle: rgba(37, 99, 235, 0.06);
    --accent-border: rgba(37, 99, 235, 0.15);

    --border: #e4e4e7;
    --border-light: #f0f0f2;

    --code-keyword: #cf222e;
    --code-string: #0a3069;
    --code-class: #0550ae;
    --code-method: #8250df;
    --code-comment: #6e7781;

    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.1);
}

/* ===================================
   RESET & BASE
   =================================== */
*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    scroll-padding-top: var(--nav-height);
}

body {
    font-family: var(--font-sans);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    transition: background-color 0.3s ease, color 0.3s ease;
}

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

ul, ol {
    list-style: none;
}

img {
    max-width: 100%;
    display: block;
}

code {
    font-family: var(--font-mono);
    font-size: 0.85em;
    background: var(--accent-subtle);
    color: var(--accent);
    padding: 2px 6px;
    border-radius: 4px;
}

strong {
    font-weight: 600;
    color: var(--text-primary);
}

/* ===================================
   LAYOUT
   =================================== */
.container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 24px;
}

/* ===================================
   NAVBAR
   =================================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    height: var(--nav-height);
    background: rgba(10, 10, 11, 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-light);
    transition: background-color 0.3s ease, border-color 0.3s ease;
}

[data-theme="light"] .navbar {
    background: rgba(250, 250, 250, 0.85);
}

.nav-container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 24px;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-logo {
    font-family: var(--font-mono);
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
    letter-spacing: -0.5px;
}

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

.nav-menu {
    display: flex;
    align-items: center;
    gap: 8px;
}

.nav-link {
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    padding: 8px 16px;
    border-radius: var(--radius-sm);
    transition: color 0.2s ease, background-color 0.2s ease;
}

.nav-link:hover {
    color: var(--text-primary);
    background: var(--accent-subtle);
}

.theme-toggle {
    background: none;
    border: 1px solid var(--border);
    color: var(--text-secondary);
    width: 38px;
    height: 38px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    transition: border-color 0.2s ease, color 0.2s ease, background-color 0.2s ease;
    margin-left: 8px;
}

.theme-toggle:hover {
    border-color: var(--accent);
    color: var(--accent);
    background: var(--accent-subtle);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}

.hamburger-line {
    display: block;
    width: 22px;
    height: 2px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: transform 0.3s ease, opacity 0.3s ease;
}

/* ===================================
   HERO
   =================================== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding-top: var(--nav-height);
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 64px;
    align-items: center;
    padding: 80px 24px;
}

.hero-greeting {
    font-family: var(--font-mono);
    font-size: 0.875rem;
    color: var(--accent);
    font-weight: 500;
    margin-bottom: 12px;
    letter-spacing: 0.5px;
}

.hero-name {
    font-size: 3.5rem;
    font-weight: 800;
    line-height: 1.1;
    letter-spacing: -2px;
    margin-bottom: 8px;
    color: var(--text-primary);
}

.hero-role {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-tertiary);
    margin-bottom: 24px;
    letter-spacing: -0.5px;
}

.hero-tagline {
    font-size: 1.05rem;
    color: var(--text-secondary);
    line-height: 1.8;
    max-width: 520px;
    margin-bottom: 36px;
}

.hero-actions {
    display: flex;
    gap: 16px;
    margin-bottom: 48px;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    font-size: 0.9rem;
    font-weight: 600;
    padding: 12px 28px;
    border-radius: var(--radius-sm);
    border: none;
    cursor: pointer;
    transition: all 0.2s ease;
    font-family: var(--font-sans);
}

.btn-primary {
    background: var(--accent);
    color: #ffffff;
}

.btn-primary:hover {
    background: var(--accent-hover);
    transform: translateY(-1px);
    box-shadow: 0 4px 16px rgba(59, 130, 246, 0.3);
}

.btn-secondary {
    background: transparent;
    color: var(--text-secondary);
    border: 1px solid var(--border);
}

.btn-secondary:hover {
    border-color: var(--text-tertiary);
    color: var(--text-primary);
    background: var(--bg-tertiary);
}

.hero-indicators {
    display: flex;
    align-items: center;
    gap: 24px;
}

.indicator {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.indicator-value {
    font-family: var(--font-mono);
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
}

.indicator-label {
    font-size: 0.75rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.indicator-divider {
    width: 1px;
    height: 36px;
    background: var(--border);
}

/* Code Block */
.hero-visual {
    display: flex;
    justify-content: center;
}

.code-block {
    background: var(--bg-code);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    width: 100%;
    max-width: 480px;
    box-shadow: var(--shadow-lg);
}

.code-header {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 14px 20px;
    border-bottom: 1px solid var(--border-light);
}

.code-dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
}

.dot-red { background: #ff5f57; }
.dot-yellow { background: #ffbd2e; }
.dot-green { background: #27c93f; }

.code-filename {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--text-tertiary);
    margin-left: 8px;
}

.code-content {
    padding: 20px 24px;
    font-family: var(--font-mono);
    font-size: 0.8rem;
    line-height: 1.9;
    overflow-x: auto;
    color: var(--text-secondary);
}

.code-content code {
    background: none;
    padding: 0;
    font-size: inherit;
    color: inherit;
}

.code-keyword { color: var(--code-keyword); }
.code-string { color: var(--code-string); }
.code-class { color: var(--code-class); }
.code-method { color: var(--code-method); }

/* ===================================
   SECTION COMMON
   =================================== */
section {
    padding: 100px 0;
}

.section-header {
    margin-bottom: 56px;
}

.section-tag {
    font-family: var(--font-mono);
    font-size: 0.85rem;
    color: var(--accent);
    font-weight: 500;
    display: block;
    margin-bottom: 12px;
}

.section-title {
    font-size: 2.25rem;
    font-weight: 700;
    letter-spacing: -1.5px;
    color: var(--text-primary);
}

.section-subtitle {
    margin-top: 12px;
    font-size: 1rem;
    color: var(--text-secondary);
    max-width: 600px;
    line-height: 1.7;
}

/* ===================================
   ABOUT
   =================================== */
.about {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-light);
    border-bottom: 1px solid var(--border-light);
}

.about-content {
    max-width: 780px;
}

.about-text {
    font-size: 1.02rem;
    color: var(--text-secondary);
    margin-bottom: 20px;
    line-height: 1.85;
}

.about-principles {
    margin-top: 40px;
    display: grid;
    grid-template-columns: 1fr;
    gap: 24px;
}

.principle {
    display: flex;
    gap: 16px;
    padding: 24px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    transition: border-color 0.2s ease;
}

.principle:hover {
    border-color: var(--accent-border);
}

.principle-icon {
    font-size: 1.4rem;
    flex-shrink: 0;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.principle h4 {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 6px;
}

.principle p {
    font-size: 0.875rem;
    color: var(--text-secondary);
    line-height: 1.7;
}

/* ===================================
   PROJECTS
   =================================== */
.projects-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 32px;
}

.project-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.project-card:hover {
    border-color: var(--accent-border);
    box-shadow: var(--shadow-md);
}

.project-featured {
    border-color: var(--accent-border);
}

.project-card-header {
    padding: 32px 32px 0;
}

.project-label {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 12px;
}

.project-badge {
    font-family: var(--font-mono);
    font-size: 0.7rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.8px;
    padding: 4px 10px;
    border-radius: 4px;
    background: var(--accent-subtle);
    color: var(--accent);
    border: 1px solid var(--accent-border);
}

.project-number {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    color: var(--text-muted);
    font-weight: 500;
}

.project-title {
    font-size: 1.4rem;
    font-weight: 700;
    letter-spacing: -0.5px;
    color: var(--text-primary);
}

.project-card-body {
    padding: 24px 32px 32px;
}

.project-section {
    margin-bottom: 24px;
}

.project-section-title {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--accent);
    margin-bottom: 10px;
}

.project-description {
    font-size: 0.95rem;
    color: var(--text-secondary);
    line-height: 1.8;
}

.project-logic-list {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.project-logic-list li {
    display: flex;
    gap: 12px;
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.75;
}

.logic-marker {
    flex-shrink: 0;
    width: 6px;
    height: 6px;
    background: var(--accent);
    border-radius: 50%;
    margin-top: 10px;
}

.project-tech {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 20px;
}

.tech-tag {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    font-weight: 500;
    padding: 5px 12px;
    background: var(--bg-tertiary);
    color: var(--text-secondary);
    border-radius: 4px;
    border: 1px solid var(--border);
    transition: border-color 0.2s ease, color 0.2s ease;
}

.tech-tag:hover {
    border-color: var(--accent-border);
    color: var(--accent);
}

.project-links {
    display: flex;
    gap: 16px;
}

.project-link {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--text-secondary);
    padding: 8px 0;
    transition: color 0.2s ease;
}

.project-link:hover {
    color: var(--accent);
}

.project-link svg {
    transition: transform 0.2s ease;
}

.project-link:hover svg {
    transform: translateY(-1px);
}

/* ===================================
   SKILLS
   =================================== */
.skills {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-light);
    border-bottom: 1px solid var(--border-light);
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
}

.skill-group {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 32px;
    transition: border-color 0.2s ease;
}

.skill-group:hover {
    border-color: var(--accent-border);
}

.skill-group-header {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 28px;
    padding-bottom: 16px;
    border-bottom: 1px solid var(--border);
}

.skill-group-icon {
    color: var(--accent);
    font-size: 0.7rem;
}

.skill-group-title {
    font-size: 1rem;
    font-weight: 700;
    letter-spacing: -0.3px;
    color: var(--text-primary);
}

.skill-list {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.skill-item {
    display: flex;
    flex-direction: column;
    gap: 3px;
}

.skill-name {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-primary);
}

.skill-detail {
    font-size: 0.8rem;
    color: var(--text-tertiary);
    line-height: 1.5;
}

/* ===================================
   CONTACT
   =================================== */
.contact {
    padding: 100px 0 80px;
}

.contact-content {
    max-width: 640px;
    margin: 0 auto;
    text-align: center;
}

.contact-content .section-header {
    margin-bottom: 24px;
}

.contact-content .section-subtitle {
    margin: 12px auto 0;
}

.contact-text {
    font-size: 1.02rem;
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 48px;
}

.contact-links {
    display: flex;
    flex-direction: column;
    gap: 16px;
    max-width: 420px;
    margin: 0 auto;
}

.contact-link-card {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 20px 24px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    transition: border-color 0.2s ease, background-color 0.2s ease;
    text-align: left;
}

.contact-link-card:hover {
    border-color: var(--accent-border);
    background: var(--bg-card-hover);
}

.contact-link-icon {
    flex-shrink: 0;
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--accent-subtle);
    border-radius: var(--radius-sm);
    color: var(--accent);
}

.contact-link-info {
    display: flex;
    flex-direction: column;
    gap: 2px;
    min-width: 0;
}

.contact-link-label {
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.contact-link-value {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-primary);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

/* ===================================
   FOOTER
   =================================== */
.footer {
    border-top: 1px solid var(--border-light);
    padding: 32px 0;
}

.footer-content {
    text-align: center;
}

.footer-text {
    font-size: 0.875rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.footer-subtext {
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-top: 4px;
}

/* ===================================
   SCROLL REVEAL
   =================================== */
.reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ===================================
   RESPONSIVE
   =================================== */
@media (max-width: 1024px) {
    .hero-content {
        grid-template-columns: 1fr;
        gap: 48px;
        padding: 60px 24px;
    }

    .hero-name {
        font-size: 2.75rem;
    }

    .hero-visual {
        order: -1;
    }

    .code-block {
        max-width: 100%;
    }

    .skills-grid {
        grid-template-columns: 1fr;
        gap: 24px;
    }
}

@media (max-width: 768px) {
    :root {
        --nav-height: 64px;
    }

    .nav-toggle {
        display: flex;
    }

    .nav-menu {
        position: fixed;
        top: var(--nav-height);
        left: 0;
        right: 0;
        bottom: 0;
        background: var(--bg-primary);
        flex-direction: column;
        align-items: center;
        justify-content: center;
        gap: 16px;
        opacity: 0;
        visibility: hidden;
        transition: opacity 0.3s ease, visibility 0.3s ease;
    }

    .nav-menu.active {
        opacity: 1;
        visibility: visible;
    }

    .nav-link {
        font-size: 1.1rem;
        padding: 12px 24px;
    }

    .theme-toggle {
        margin-left: 0;
        margin-top: 8px;
    }

    /* Hamburger animation */
    .nav-toggle.active .hamburger-line:nth-child(1) {
        transform: rotate(45deg) translate(5px, 5px);
    }

    .nav-toggle.active .hamburger-line:nth-child(2) {
        opacity: 0;
    }

    .nav-toggle.active .hamburger-line:nth-child(3) {
        transform: rotate(-45deg) translate(5px, -5px);
    }

    .hero {
        min-height: auto;
        padding-top: calc(var(--nav-height) + 20px);
    }

    .hero-content {
        padding: 40px 20px 60px;
    }

    .hero-name {
        font-size: 2.2rem;
        letter-spacing: -1px;
    }

    .hero-role {
        font-size: 1.2rem;
    }

    .hero-tagline {
        font-size: 0.95rem;
    }

    .hero-actions {
        flex-direction: column;
        gap: 12px;
    }

    .btn {
        justify-content: center;
        width: 100%;
    }

    .hero-indicators {
        gap: 16px;
    }

    .indicator-value {
        font-size: 0.9rem;
    }

    .indicator-label {
        font-size: 0.65rem;
    }

    .code-content {
        font-size: 0.7rem;
        padding: 16px 18px;
    }

    section {
        padding: 72px 0;
    }

    .section-title {
        font-size: 1.75rem;
        letter-spacing: -1px;
    }

    .project-card-header {
        padding: 24px 24px 0;
    }

    .project-card-body {
        padding: 20px 24px 24px;
    }

    .project-title {
        font-size: 1.2rem;
    }

    .project-logic-list li {
        font-size: 0.85rem;
    }

    .about-principles {
        gap: 16px;
    }

    .principle {
        padding: 20px;
    }

    .contact-link-card {
        padding: 16px 20px;
    }
}

@media (max-width: 480px) {
    .hero-name {
        font-size: 1.85rem;
    }

    .hero-indicators {
        flex-wrap: wrap;
        gap: 12px;
    }

    .indicator-divider {
        display: none;
    }

    .indicator {
        background: var(--bg-card);
        border: 1px solid var(--border);
        padding: 10px 16px;
        border-radius: var(--radius-sm);
    }

    .project-card-header {
        padding: 20px 20px 0;
    }

    .project-card-body {
        padding: 16px 20px 20px;
    }

    .skill-group {
        padding: 24px;
    }
}