/* ============================================================
   ULAŞ UÇRAK — PORTFOLIO
   Design direction: ground-station / telemetry aesthetic.
   Deep space navy, electric blue/cyan accent, monospace
   technical labels echoing satellite control interfaces.
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@400;500;600;700&family=IBM+Plex+Mono:wght@400;500;600&display=swap');

/* ============================================================
   DESIGN TOKENS
   ============================================================ */
:root {
    --bg: #f4f6fb;
    --bg-elevated: #ffffff;
    --text: #0d1b27;
    --text-muted: #5a6b7d;
    --accent: #0a84ff;
    --accent-2: #00c2c7;
    --border: #e2e8f2;
    --grid-line: rgba(10, 132, 255, 0.06);
    --shadow: 0 10px 40px rgba(13, 27, 39, 0.08);
    --shadow-strong: 0 20px 60px rgba(13, 27, 39, 0.14);

    --font-display: 'Space Grotesk', sans-serif;
    --font-mono: 'IBM Plex Mono', monospace;

    --speed: 0.35s;
    --ease: cubic-bezier(0.22, 1, 0.36, 1);
    --maxw: 1140px;
}

body.dark-theme {
    --bg: #070b14;
    --bg-elevated: #0e1626;
    --text: #e8eef7;
    --text-muted: #8595a8;
    --accent: #2e9bff;
    --accent-2: #00e0d4;
    --border: #1c2a3f;
    --grid-line: rgba(46, 155, 255, 0.07);
    --shadow: 0 10px 40px rgba(0, 0, 0, 0.4);
    --shadow-strong: 0 20px 60px rgba(0, 0, 0, 0.55);
}

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

html {
    scroll-behavior: smooth;
    scroll-padding-top: 90px;
}

body {
    font-family: var(--font-display);
    background-color: var(--bg);
    color: var(--text);
    line-height: 1.65;
    transition: background-color var(--speed) var(--ease), color var(--speed) var(--ease);
    overflow-x: hidden;
}

/* Faint engineering grid in the background */
body::before {
    content: "";
    position: fixed;
    inset: 0;
    background-image:
        linear-gradient(var(--grid-line) 1px, transparent 1px),
        linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
    background-size: 46px 46px;
    z-index: -1;
    pointer-events: none;
}

::selection {
    background: var(--accent);
    color: #fff;
}

/* ============================================================
   NAVBAR
   ============================================================ */
header {
    position: sticky;
    top: 0;
    z-index: 100;
    background-color: color-mix(in srgb, var(--bg) 82%, transparent);
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
    border-bottom: 1px solid var(--border);
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1.5rem;
    padding: 1rem 2rem;
    max-width: var(--maxw);
    margin: 0 auto;
}

.logo {
    font-family: var(--font-mono);
    font-size: 1.05rem;
    font-weight: 600;
    letter-spacing: -0.02em;
    color: var(--text);
    white-space: nowrap;
}

.logo::before {
    content: "◆ ";
    color: var(--accent);
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 1.75rem;
    flex-wrap: wrap;
    justify-content: flex-end;
}

.nav-links a {
    position: relative;
    text-decoration: none;
    color: var(--text-muted);
    font-size: 0.9rem;
    font-weight: 500;
    transition: color var(--speed) var(--ease);
}

.nav-links a::after {
    content: "";
    position: absolute;
    left: 0;
    bottom: -4px;
    width: 0;
    height: 2px;
    background: var(--accent);
    transition: width var(--speed) var(--ease);
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--text);
}

.nav-links a:hover::after,
.nav-links a.active::after {
    width: 100%;
}

#theme-toggle {
    background: none;
    border: 1px solid var(--border);
    border-radius: 10px;
    width: 42px;
    height: 42px;
    cursor: pointer;
    font-size: 1.1rem;
    color: var(--text);
    transition: border-color var(--speed) var(--ease), transform var(--speed) var(--ease);
    flex-shrink: 0;
}

#theme-toggle:hover {
    border-color: var(--accent);
    transform: rotate(-12deg);
}

/* ============================================================
   HERO
   ============================================================ */
#hero {
    min-height: calc(100vh - 74px);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    padding: 3rem 2rem;
    max-width: var(--maxw);
    margin: 0 auto;
    position: relative;
}

.hero-eyebrow {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    color: var(--accent);
    margin-bottom: 1.75rem;
    display: flex;
    align-items: center;
    gap: 0.6rem;
}

.hero-eyebrow::before {
    content: "";
    width: 7px;
    height: 7px;
    border-radius: 50%;
    background: var(--accent-2);
    animation: pulse 2.4s infinite;
}

@keyframes pulse {
    0% { box-shadow: 0 0 0 0 color-mix(in srgb, var(--accent-2) 60%, transparent); }
    70% { box-shadow: 0 0 0 10px transparent; }
    100% { box-shadow: 0 0 0 0 transparent; }
}

/* Profile avatar with rotating ring */
.avatar-wrap {
    position: relative;
    margin-bottom: 2rem;
    display: grid;
    place-items: center;
}

.hero-avatar {
    width: 150px;
    height: 150px;
    border-radius: 50%;
    object-fit: cover;
    border: 2px solid var(--border);
    padding: 5px;
    background: var(--bg-elevated);
    box-shadow: var(--shadow);
}

.avatar-wrap::before {
    content: "";
    position: absolute;
    width: 174px;
    height: 174px;
    border-radius: 50%;
    border: 1.5px dashed var(--accent);
    opacity: 0.4;
    animation: spin 22s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

#hero h1 {
    font-size: clamp(2.4rem, 6vw, 4.2rem);
    font-weight: 700;
    line-height: 1.05;
    letter-spacing: -0.03em;
    margin-bottom: 1.25rem;
    max-width: 14ch;
}

.highlight {
    color: var(--accent);
}

#hero > p {
    font-size: clamp(1.05rem, 2.2vw, 1.3rem);
    color: var(--text-muted);
    max-width: 52ch;
    margin-bottom: 2.5rem;
}

.hero-actions {
    display: flex;
    align-items: center;
    gap: 1rem;
    flex-wrap: wrap;
    justify-content: center;
}

/* ============================================================
   BUTTONS
   ============================================================ */
.btn {
    font-family: var(--font-display);
    font-size: 0.95rem;
    font-weight: 600;
    padding: 0.85rem 1.75rem;
    border-radius: 10px;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    cursor: pointer;
    border: 1px solid transparent;
    transition: transform var(--speed) var(--ease), box-shadow var(--speed) var(--ease),
        background-color var(--speed) var(--ease), color var(--speed) var(--ease),
        border-color var(--speed) var(--ease);
}

.btn-primary {
    background-color: var(--accent);
    color: #fff;
    box-shadow: 0 8px 24px color-mix(in srgb, var(--accent) 35%, transparent);
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 14px 32px color-mix(in srgb, var(--accent) 45%, transparent);
}

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

.btn-outline:hover {
    transform: translateY(-3px);
    border-color: var(--accent);
    color: var(--accent);
}

/* ============================================================
   SOCIAL LINKS
   ============================================================ */
.social-links {
    display: flex;
    gap: 0.75rem;
    margin: 2.25rem 0 0;
    justify-content: center;
}

.social-links a {
    display: grid;
    place-items: center;
    width: 44px;
    height: 44px;
    border-radius: 10px;
    border: 1px solid var(--border);
    color: var(--text-muted);
    background: var(--bg-elevated);
    transition: color var(--speed) var(--ease), transform var(--speed) var(--ease),
        border-color var(--speed) var(--ease);
}

.social-links a:hover {
    color: var(--accent);
    border-color: var(--accent);
    transform: translateY(-4px);
}

/* ============================================================
   SECTIONS
   ============================================================ */
section {
    max-width: var(--maxw);
    margin: 0 auto;
    padding: 5.5rem 2rem;
}

.section-head {
    display: flex;
    align-items: baseline;
    gap: 1rem;
    margin-bottom: 2.5rem;
}

.section-index {
    font-family: var(--font-mono);
    font-size: 0.85rem;
    color: var(--accent);
    font-weight: 500;
    white-space: nowrap;
}

section h2 {
    font-size: clamp(1.7rem, 4vw, 2.4rem);
    font-weight: 700;
    letter-spacing: -0.02em;
    white-space: nowrap;
}

.section-rule {
    flex: 1;
    height: 1px;
    background: var(--border);
    align-self: center;
}

/* Summary as a lead paragraph */
#summary p {
    font-size: clamp(1.15rem, 2.5vw, 1.5rem);
    font-weight: 400;
    line-height: 1.55;
    color: var(--text);
    max-width: 60ch;
    letter-spacing: -0.01em;
}

/* ============================================================
   CARD GRID
   ============================================================ */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.25rem;
}

.card {
    position: relative;
    background-color: var(--bg-elevated);
    padding: 1.75rem;
    border-radius: 16px;
    border: 1px solid var(--border);
    transition: transform var(--speed) var(--ease), box-shadow var(--speed) var(--ease),
        border-color var(--speed) var(--ease);
    overflow: hidden;
}

.card::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 3px;
    background: linear-gradient(90deg, var(--accent), var(--accent-2));
    transform: scaleX(0);
    transform-origin: left;
    transition: transform var(--speed) var(--ease);
}

.card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-strong);
    border-color: color-mix(in srgb, var(--accent) 30%, var(--border));
}

.card:hover::before {
    transform: scaleX(1);
}

.card h3 {
    font-size: 1.15rem;
    font-weight: 600;
    letter-spacing: -0.01em;
    margin-bottom: 0.4rem;
    color: var(--text);
}

.card p:not(.card-tag) {
    color: var(--text-muted);
    font-size: 0.95rem;
}

.card-tag {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    font-weight: 500;
    color: var(--accent);
    margin-bottom: 0.9rem;
    letter-spacing: -0.01em;
}

.card-wide {
    grid-column: span 2;
}

.card-featured::after {
    content: "★ FEATURED";
    position: absolute;
    top: 1rem;
    right: 1rem;
    font-family: var(--font-mono);
    font-size: 0.65rem;
    letter-spacing: 0.1em;
    color: var(--accent-2);
    opacity: 0.85;
}

/* Skills chips */
.chip-row {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-top: 0.25rem;
}

.chip {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    padding: 0.3rem 0.7rem;
    border-radius: 7px;
    background: color-mix(in srgb, var(--accent) 8%, transparent);
    border: 1px solid color-mix(in srgb, var(--accent) 18%, transparent);
    color: var(--text);
}

/* ============================================================
   CONTACT
   ============================================================ */
#contact {
    text-align: center;
}

#contact .section-head {
    justify-content: center;
}

.contact-cta {
    font-size: clamp(1.5rem, 4vw, 2.2rem);
    font-weight: 700;
    letter-spacing: -0.02em;
    margin-bottom: 1.5rem;
}

.contact-email {
    font-family: var(--font-mono);
    font-size: 1.1rem;
    color: var(--accent);
    text-decoration: none;
    border-bottom: 1px solid transparent;
    transition: border-color var(--speed) var(--ease);
}

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

/* ============================================================
   FOOTER
   ============================================================ */
footer {
    border-top: 1px solid var(--border);
    text-align: center;
    padding: 2.5rem 2rem;
    color: var(--text-muted);
    font-family: var(--font-mono);
    font-size: 0.82rem;
}

/* ============================================================
   SCROLL REVEAL
   ============================================================ */
.fade-in {
    opacity: 0;
    transform: translateY(28px);
    transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ============================================================
   BACK TO TOP
   ============================================================ */
#back-to-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 46px;
    height: 46px;
    border-radius: 12px;
    border: 1px solid var(--border);
    background: var(--bg-elevated);
    color: var(--text);
    font-size: 1.2rem;
    cursor: pointer;
    opacity: 0;
    pointer-events: none;
    transform: translateY(12px);
    transition: opacity var(--speed) var(--ease), transform var(--speed) var(--ease),
        border-color var(--speed) var(--ease);
    box-shadow: var(--shadow);
    z-index: 90;
}

#back-to-top.show {
    opacity: 1;
    pointer-events: auto;
    transform: translateY(0);
}

#back-to-top:hover {
    border-color: var(--accent);
    color: var(--accent);
}

/* ============================================================
   RESPONSIVE
   ============================================================ */
@media (max-width: 768px) {
    nav {
        flex-wrap: wrap;
        padding: 0.85rem 1.25rem;
        gap: 0.75rem 1rem;
    }

    .nav-links {
        order: 3;
        width: 100%;
        gap: 1rem;
        justify-content: center;
    }

    .card-wide {
        grid-column: span 1;
    }

    section {
        padding: 4rem 1.25rem;
    }

    .card-featured::after {
        display: none;
    }

    .section-head h2 {
        white-space: normal;
    }
}

@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
}