/* ============================================================
   Base
   ============================================================ */

:root {
    --color-dark: #222;
    --color-nav: rgba(30, 30, 30, 0.88);
    --color-blue: #2177c8;
    --color-blue-dark: #1860a8;
    --color-text: #1a1a1a;
    --color-muted: #555;
    --color-surface: #f5f7fa;
    --color-card-bg: #ffffff;
    --color-card-border: #d0d7e0;
    --color-badge-bg: #e8f0fb;
    --color-badge-border: #c0d5f0;
    --color-badge-text: #1860a8;
    --color-divider: #e2e6eb;
    --nav-height: 52px;
    --content-max: 860px;
    --font: 'Source Sans 3', sans-serif;
}

/* Dark mode — respects OS preference unless overridden by toggle */
@media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) {
        --color-dark: #e8e8e8;
        --color-nav: rgba(10, 10, 18, 0.92);
        --color-text: #e0e0e8;
        --color-muted: #9aa0ac;
        --color-surface: #0f1117;
        --color-card-bg: #1a1d2a;
        --color-card-border: #2e3348;
        --color-badge-bg: #1a2540;
        --color-badge-border: #2a3d6a;
        --color-badge-text: #7ab3e8;
        --color-divider: #1e2230;
    }
}

/* Explicit dark preference set by toggle */
[data-theme="dark"] {
    --color-dark: #e8e8e8;
    --color-nav: rgba(10, 10, 18, 0.92);
    --color-text: #e0e0e8;
    --color-muted: #9aa0ac;
    --color-surface: #0f1117;
    --color-card-bg: #1a1d2a;
    --color-card-border: #2e3348;
    --color-badge-bg: #1a2540;
    --color-badge-border: #2a3d6a;
    --color-badge-text: #7ab3e8;
    --color-divider: #1e2230;
}

/* Explicit light preference set by toggle */
[data-theme="light"] {
    --color-dark: #222;
    --color-nav: rgba(30, 30, 30, 0.88);
    --color-text: #1a1a1a;
    --color-muted: #555;
    --color-surface: #f5f7fa;
    --color-card-bg: #ffffff;
    --color-card-border: #d0d7e0;
    --color-badge-bg: #e8f0fb;
    --color-badge-border: #c0d5f0;
    --color-badge-text: #1860a8;
    --color-divider: #e2e6eb;
}

*, *::before, *::after {
    box-sizing: border-box;
}

:root {
    scroll-behavior: smooth;
}

html, body {
    margin: 0;
    min-height: 100vh;
    font-family: var(--font);
    color: var(--color-text);
    background: var(--color-surface);
}

/* ============================================================
   Top Navigation
   ============================================================ */

.topnav {
    background-color: var(--color-nav);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    overflow: hidden;
    position: sticky;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 100;
    height: var(--nav-height);
    display: flex;
    align-items: stretch;
}

.topnav a,
.topnav .brand {
    display: flex;
    align-items: center;
    color: #f2f2f2;
    text-align: center;
    padding: 0 1em;
    text-decoration: none;
    font-size: 1em;
    white-space: nowrap;
    transition: background-color 0.2s;
}

.topnav .brand {
    font-weight: 900;
    letter-spacing: 0.04em;
}

.topnav a:hover {
    background-color: var(--color-blue);
    color: white;
}

.topnav a.active {
    background-color: var(--color-blue);
    color: white;
}

.topnav a:hover.active {
    background-color: var(--color-blue-dark);
}

/* Spacer pushes icon to the right */
.topnav::after {
    content: '';
    flex: 1;
}

/* Hamburger icon button */
.topnav .icon {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0 12px;
    height: var(--nav-height);
    flex-direction: column;
    justify-content: center;
    gap: 5px;
    transition: background-color 0.2s;
    align-self: stretch;
}

.topnav .icon:hover {
    background-color: var(--color-blue);
}

.bar1,
.bar2,
.bar3 {
    width: 24px;
    height: 3px;
    background-color: #f2f2f2;
    border-radius: 2px;
    transition: 0.35s;
    pointer-events: none;
}

/* Hamburger → X animation */
.responsive .bar1 {
    transform: translate(0, 8px) rotate(-45deg);
}

.responsive .bar2 {
    opacity: 0;
    transform: scaleX(0);
}

.responsive .bar3 {
    transform: translate(0, -8px) rotate(45deg);
}

/* ============================================================
   Mobile nav
   ============================================================ */

@media screen and (max-width: 640px) {
    .topnav {
        flex-wrap: wrap;
        height: auto;
        min-height: var(--nav-height);
    }

    .topnav a:not(.brand) {
        display: none;
    }

    .topnav .icon {
        display: flex;
        margin-left: auto;
    }

    .topnav::after {
        display: none;
    }

    .topnav.responsive {
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
    }

    .topnav.responsive a:not(.brand) {
        display: flex;
        width: 100%;
        text-align: left;
        padding: 0.85em 1.25em;
        border-top: 1px solid var(--color-divider);
    }

    .topnav.responsive .icon {
        position: absolute;
        right: 0;
        top: 0;
        height: var(--nav-height);
    }
}

/* ============================================================
   Hero
   ============================================================ */

.hero {
    min-height: 100svh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    background: linear-gradient(135deg, #1a1a2e 0%, #16213e 40%, #1860a8 100%);
    padding: 2rem 1.5rem;
    scroll-margin-top: var(--nav-height);
}

.hero-content {
    max-width: 600px;
}

.hero h1 {
    margin: 0 0 0.35em;
    font-size: clamp(2.2rem, 6vw, 4rem);
    font-weight: 900;
    color: #ffffff;
    letter-spacing: 0.02em;
    line-height: 1.1;
}

.hero-tagline {
    margin: 0 0 2rem;
    font-size: clamp(1rem, 2.5vw, 1.25rem);
    color: rgba(255,255,255,0.75);
    letter-spacing: 0.03em;
}

.hero-cta {
    display: inline-block;
    background: var(--color-blue);
    color: #fff;
    text-decoration: none;
    padding: 0.75em 2em;
    border-radius: 2em;
    font-size: 1.05rem;
    font-weight: 700;
    transition: background-color 0.2s, transform 0.15s;
}

.hero-cta:hover {
    background: var(--color-blue-dark);
    transform: translateY(-2px);
}

/* ============================================================
   Main content sections
   ============================================================ */

main {
    max-width: var(--content-max);
    margin: 0 auto;
    padding: 0 1.5rem;
}

.content {
    padding: 3em 0;
    border-bottom: 1px solid var(--color-divider);
}

.content:last-child {
    border-bottom: none;
}

section {
    scroll-margin-top: calc(var(--nav-height) + 1rem);
}

h2 {
    margin: 0 0 0.6em;
    font-size: 1.75rem;
    font-weight: 900;
    color: var(--color-dark);
}

p {
    line-height: 1.7;
    color: var(--color-muted);
    margin: 0 0 1.25em;
}

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

p a:hover {
    text-decoration: underline;
}

/* ============================================================
   Technology badges
   ============================================================ */

.badge-list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5em;
    margin-top: 1.25em;
}

.badge {
    display: inline-block;
    background: var(--color-badge-bg);
    color: var(--color-badge-text);
    font-size: 0.875rem;
    font-weight: 700;
    padding: 0.3em 0.85em;
    border-radius: 2em;
    border: 1.5px solid var(--color-badge-border);
    letter-spacing: 0.02em;
}

/* ============================================================
   Contact buttons
   ============================================================ */

.contact-links {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75em;
    margin-top: 0.5em;
}

.contact-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5em;
    background: var(--color-card-bg);
    color: var(--color-text);
    text-decoration: none;
    padding: 0.65em 1.25em;
    border-radius: 0.5em;
    font-size: 1rem;
    font-weight: 700;
    border: 1.5px solid var(--color-card-border);
    transition: border-color 0.2s, box-shadow 0.2s, transform 0.15s, background-color 0.2s;
}

.contact-btn svg {
    width: 18px;
    height: 18px;
    flex-shrink: 0;
}

.contact-btn:hover {
    border-color: var(--color-blue);
    box-shadow: 0 4px 12px rgba(33,119,200,0.15);
    transform: translateY(-2px);
    color: var(--color-blue);
}

/* ============================================================
   Footer
   ============================================================ */

.botnav {
    background-color: var(--color-nav);
    overflow: hidden;
    width: 100%;
    display: flex;
    align-items: center;
}

.botnav a {
    display: block;
    color: #f2f2f2;
    text-align: center;
    padding: 14px 16px;
    text-decoration: none;
    font-size: 0.9em;
    transition: background-color 0.2s;
}

.botnav a:hover {
    background-color: var(--color-blue);
    color: white;
}

#copyright {
    margin-left: auto;
    color: rgba(242,242,242,0.55);
    padding: 14px 16px;
    font-size: 0.9em;
}

/* ============================================================
   Language visibility
   ============================================================ */

:lang(en-US) {
    display: none;
}

:lang(de-DE) {
    display: block;
}

/* ============================================================
   Service sub-blocks
   ============================================================ */

h3 {
    margin: 0 0 0.4em;
    font-size: 1.15rem;
    font-weight: 700;
    color: var(--color-dark);
}

.service-block {
    padding: 1.5em 0;
    border-top: 1px solid var(--color-divider);
}

.service-block:first-of-type {
    border-top: none;
    padding-top: 0.5em;
}

/* ============================================================
   Theme toggle button
   ============================================================ */

#theme-toggle {
    background: none;
    border: none;
    cursor: pointer;
    padding: 0 14px;
    height: var(--nav-height);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #f2f2f2;
    transition: background-color 0.2s;
    flex-shrink: 0;
}

#theme-toggle:hover {
    background-color: var(--color-blue);
}

#theme-toggle svg {
    width: 20px;
    height: 20px;
    pointer-events: none;
}

/* ============================================================
   Error pages
   ============================================================ */

.error-page {
    min-height: calc(100svh - var(--nav-height));
}

.error-code {
    margin: 0 0 0.1em;
    font-size: clamp(4rem, 18vw, 8rem);
    font-weight: 900;
    color: rgba(255,255,255,0.2);
    line-height: 1;
    letter-spacing: -0.02em;
}

/* ============================================================
   Theme toggle icon visibility
   ============================================================ */

/* Light mode: show moon, hide sun */
.icon-sun { display: none; }
.icon-moon { display: block; }

/* Dark mode: show sun, hide moon */
[data-theme="dark"] .icon-sun,
@media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) .icon-sun { display: block; }
}

[data-theme="dark"] .icon-sun { display: block; }
[data-theme="dark"] .icon-moon { display: none; }

@media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) #theme-toggle .icon-sun { display: block; }
    :root:not([data-theme="light"]) #theme-toggle .icon-moon { display: none; }
}