/* ============================================
   CSS CUSTOM PROPERTIES (THEME SYSTEM)
   ============================================ */
:root {
    --bg:             #0d1520;
    --bg-alt:         #111827;
    --bg-card:        #141e2e;
    --bg-skill:       #1a2235;
    --text:           #f0f0f0;
    --text-sub:       #c8d0e0;
    --text-muted:     #b0b0b0;
    --text-dim:       #888;
    --accent:         #4f8ef7;
    --accent-rgb:     79, 142, 247;
    --border:         #2a3550;
    --border-footer:  #222;
}

[data-theme="light"] {
    --bg:             #f7f8fa;
    --bg-alt:         #eef0f5;
    --bg-card:        #ffffff;
    --bg-skill:       #eef3ff;
    --text:           #1a1a2e;
    --text-sub:       #333344;
    --text-muted:     #555566;
    --text-dim:       #666;
    --accent:         #4f8ef7;
    --accent-rgb:     79, 142, 247;
    --border:         #c8d4e8;
    --border-footer:  #e0e0e0;
}

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background-color: var(--bg);
    color: var(--text);
    line-height: 1.6;
    transition: background-color 0.25s, color 0.25s;
}

h1, h2, h3 {
    line-height: 1.2;
    font-weight: 700;
}

h1 { font-size: 2rem; }
h2 { font-size: 1.3rem; }

a {
    color: var(--accent);
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

/* ============================================
   CONTROLS (LANGUAGE + THEME TOGGLES)
   ============================================ */
.controls {
    position: fixed;
    top: 1.5rem;
    right: 1.5rem;
    display: flex;
    gap: 0.5rem;
    z-index: 100;
}

.lang-toggle,
.theme-toggle {
    background: transparent;
    border: 2px solid var(--accent);
    color: var(--accent);
    padding: 0.4rem 0.8rem;
    font-size: 0.85rem;
    font-weight: 700;
    cursor: pointer;
    border-radius: 4px;
    transition: background-color 0.2s, color 0.2s;
    line-height: 1;
}

.lang-toggle:hover,
.theme-toggle:hover {
    background-color: var(--accent);
    color: var(--bg);
}

.theme-toggle {
    padding: 0.3rem 0.45rem;
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-toggle .material-symbols-outlined {
    font-size: 1.1rem;
}

/* ============================================
   HERO HEADER
   ============================================ */
.exp-hero {
    background-color: var(--bg);
    background-image: radial-gradient(circle, rgba(var(--accent-rgb), 0.10) 1px, transparent 1px);
    background-size: 28px 28px;
    border-bottom: 1px solid var(--border);
    padding: 5rem 1.5rem 3.5rem;
    position: relative;
    overflow: hidden;
}

.exp-hero::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 700px;
    height: 300px;
    background: radial-gradient(ellipse, rgba(var(--accent-rgb), 0.06) 0%, transparent 70%);
    pointer-events: none;
}

.exp-hero-content {
    max-width: 900px;
    margin: 0 auto;
    position: relative;
    z-index: 1;
}

.back-link {
    display: block;
    font-size: 0.9rem;
    color: var(--text-dim);
    margin-bottom: 1.25rem;
    transition: color 0.2s;
}

.back-link:hover {
    color: var(--accent);
    text-decoration: none;
}

.exp-company-name {
    display: block;
    padding: 0.3rem 1rem;
    background-color: rgba(var(--accent-rgb), 0.12);
    border: 1px solid rgba(var(--accent-rgb), 0.35);
    border-radius: 100px;
    font-size: 0.85rem;
    color: var(--accent);
    letter-spacing: 0.04em;
    margin-bottom: 1rem;
    width: fit-content;
}

.exp-hero-content h1 {
    color: var(--text);
    margin-bottom: 0.5rem;
}

.exp-period-label {
    color: var(--text-dim);
    font-size: 0.95rem;
}

/* ============================================
   MAIN CONTENT
   ============================================ */
main {
    max-width: 900px;
    margin: 0 auto;
}

.exp-section {
    padding: 4rem 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 2.5rem;
}

.exp-block h2 {
    position: relative;
    padding-bottom: 0.5rem;
    margin-bottom: 1rem;
    color: var(--accent);
    font-size: 1rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
}

.exp-block h2::after {
    content: '';
    position: absolute;
    left: 0;
    bottom: 0;
    width: 2rem;
    height: 2px;
    background-color: var(--accent);
    border-radius: 2px;
    opacity: 0.5;
}

.exp-block p {
    color: var(--text-sub);
    max-width: 700px;
    font-size: 1rem;
}

/* ============================================
   TECH SECTION
   ============================================ */
.tech-section {
    background-color: var(--bg-alt);
    padding: 3.5rem 1.5rem;
    margin: 0;
    max-width: 100%;
}

.tech-section h2 {
    position: relative;
    max-width: 900px;
    margin: 0 auto 1.5rem;
    padding-bottom: 0.5rem;
    font-size: 1rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-dim);
}

.tech-chips {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    max-width: 900px;
    margin: 0 auto;
}

.tech-chip {
    padding: 0.5rem 1.1rem;
    background-color: var(--bg-skill);
    border: 1px solid var(--border);
    border-radius: 100px;
    font-size: 0.9rem;
    color: var(--text-sub);
}

/* ============================================
   CTA SECTION
   ============================================ */
.cta-section {
    padding: 4rem 1.5rem;
    text-align: center;
    border-top: 1px solid var(--border);
}

.cta-section p {
    color: var(--text-muted);
    margin-bottom: 1.5rem;
    font-size: 1.1rem;
}

.cta-button {
    display: inline-block;
    padding: 0.75rem 2rem;
    background-color: var(--accent);
    color: var(--bg);
    font-weight: 700;
    border-radius: 4px;
    text-decoration: none;
    transition: opacity 0.2s;
}

.cta-button:hover {
    opacity: 0.85;
    text-decoration: none;
}

/* ============================================
   FOOTER
   ============================================ */
.footer {
    text-align: center;
    padding: 2.5rem 1.5rem;
    border-top: 1px solid var(--border-footer);
    font-size: 0.9rem;
    color: var(--text-dim);
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    margin-top: 0.75rem;
}

/* ============================================
   RESPONSIVE
   ============================================ */
@media (max-width: 768px) {
    h1 { font-size: 1.6rem; }

    .exp-hero {
        padding: 4rem 1.25rem 2.5rem;
    }

    .exp-section {
        padding: 3rem 1.25rem;
        gap: 2rem;
    }

    .tech-section {
        padding: 2.5rem 1.25rem;
    }

    .cta-section {
        padding: 3rem 1.25rem;
    }
}