/* ─── Design Tokens ─────────────────────────────────────── */
:root {
    --red:        #d82e26;
    --red-dark:   #b01f18;
    --red-light:  #f04039;
    --red-glow:   rgba(216, 46, 38, 0.18);
    --red-subtle: rgba(216, 46, 38, 0.06);
    --ink:        #0f0f0f;
    --ink-muted:  #4a4a4a;
    --surface:    #ffffff;
    --surface-2:  #f7f7f7;
    --border:     rgba(0, 0, 0, 0.07);
    --shadow-sm:  0 2px 8px rgba(0, 0, 0, 0.06);
    --shadow-md:  0 8px 32px rgba(0, 0, 0, 0.10);
    --shadow-lg:  0 20px 60px rgba(0, 0, 0, 0.14);
    --shadow-red: 0 8px 32px rgba(216, 46, 38, 0.22);
    --radius-sm:  8px;
    --radius-md:  14px;
    --radius-lg:  22px;
    --radius-pill:999px;
    --ease:       cubic-bezier(.4, 0, .2, 1);
    --ease-spring:cubic-bezier(.34, 1.56, .64, 1);
}

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

/* ─── Font Faces ─────────────────────────────────────────── */
@font-face {
    font-family: 'AvenirNext';
    src: url('fonts/AvenirNextCyr-Thin.ttf');
    font-weight: 100;
}
@font-face {
    font-family: 'AvenirNext';
    src: url('fonts/AvenirNextCyr-Light.ttf');
    font-weight: 300;
}

/* ─── Base ───────────────────────────────────────────────── */
html {
    scroll-behavior: smooth;
}

body {
    min-height: 100vh;
    background-color: var(--surface);
    font-family: 'AvenirNext', system-ui, sans-serif;
    font-weight: 300;
    color: var(--ink);
    padding-top: 80px;
    -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4, h5 {
    color: var(--ink);
    letter-spacing: -0.02em;
    line-height: 1.2;
}

p {
    color: var(--ink-muted);
    line-height: 1.75;
}

/* ─── Header ─────────────────────────────────────────────── */
header {
    height: 80px;
    background: rgba(255, 255, 255, 0.72);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    border-bottom: 1px solid var(--border);
    display: flex;
    justify-content: flex-end;
    align-items: center;
    transition: background 0.3s var(--ease), box-shadow 0.3s var(--ease);
}

header:hover {
    background: rgba(255, 255, 255, 0.92);
    box-shadow: var(--shadow-md);
}

header a:first-child {
    margin-right: auto;
}

.headerLogo {
    height: 70%;
    padding-left: 28px;
}

.headerLogo img {
    height: 100%;
    width: auto;
    filter: drop-shadow(0 2px 6px rgba(0,0,0,0.08));
}

/* ─── Nav ────────────────────────────────────────────────── */
header nav {
    display: flex;
    align-items: stretch;
    height: 100%;
}

nav ul {
    width: 100%;
    padding-right: 24px;
    list-style: none;
    display: flex;
    align-items: center;
    gap: 2px;
    height: 100%;
}

nav a {
    padding: 8px 16px;
    text-decoration: none;
    display: flex;
    align-items: center;
    color: var(--ink);
    font-weight: 600;
    font-size: 0.875rem;
    letter-spacing: 0.07em;
    text-transform: uppercase;
    border-radius: var(--radius-pill);
    transition: color 0.2s var(--ease), background 0.2s var(--ease);
}

nav a:hover {
    color: var(--red);
    background: var(--red-subtle);
}

/* ─── Sidebar (mobile menu) ──────────────────────────────── */
.sidebar {
    position: fixed;
    top: 0;
    right: 0;
    height: 100vh;
    width: 260px;
    z-index: 999;
    background: rgba(255, 255, 255, 0.94);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    border-left: 1px solid var(--border);
    box-shadow: -20px 0 60px rgba(0, 0, 0, 0.10);
    display: none;
    flex-direction: column;
    align-items: flex-start;
    justify-content: flex-start;
    padding: 16px 12px 16px 44px;
    gap: 20px;
}

.sidebar li {
    width: 100%;
}

.sidebar a {
    padding: 8px 16px;
    display: inline-flex;
    align-items: center;
    border-radius: var(--radius-pill);
    font-size: 0.875rem;
    font-weight: 600;
    letter-spacing: 0.07em;
    text-transform: uppercase;
    color: var(--ink);
}

.menuButton {
    display: none;
}

/* ─── Buttons ────────────────────────────────────────────── */
.button-self {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: linear-gradient(135deg, var(--red), var(--red-dark));
    border: none;
    border-radius: var(--radius-pill);
    color: white;
    text-decoration: none;
    cursor: pointer;
    padding: 13px 30px;
    font-family: inherit;
    font-weight: 600;
    font-size: 0.9rem;
    letter-spacing: 0.04em;
    box-shadow: var(--shadow-red);
    transition: transform 0.2s var(--ease-spring),
                box-shadow 0.2s var(--ease),
                filter 0.2s var(--ease);
}

.button-self:hover {
    transform: translateY(-2px) scale(1.02);
    box-shadow: 0 12px 40px rgba(216, 46, 38, 0.35);
    filter: brightness(1.08);
}

.button-self:active {
    transform: translateY(0) scale(0.98);
}

/* ─── Carousel ───────────────────────────────────────────── */
.carousel-indiv-height {
    position: relative;
    height: calc(100vw * 0.42);
    min-height: 260px;
    display: flex;
}

.carousel-pic {
    position: relative;
    overflow: hidden;
    height: 100%;
    width: 100%;
}

.carousel-pic::after {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(
        to bottom,
        transparent 30%,
        rgba(15, 15, 15, 0.55) 100%
    );
    pointer-events: none;
}

.carousel-caption {
    z-index: 2;
}

.carousel-caption h5 {
    font-size: clamp(0.75rem, 2vw, 1.2rem);
    font-weight: 300;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    text-shadow: 0 2px 20px rgba(0,0,0,0.3);
    color: white;
}

/* ─── Flip Cards ─────────────────────────────────────────── */
.flip-box {
    transform-style: preserve-3d;
    perspective: 1000px;
    cursor: pointer;
}

.flip-box-front, .flip-box-back {
    background-size: cover;
    background-position: center;
    border-radius: var(--radius-lg);
    min-height: 400px;
    transition: transform 0.75s cubic-bezier(.4, .2, .2, 1);
    backface-visibility: hidden;
    box-shadow: var(--shadow-lg);
}

.flip-box-front {
    transform: rotateY(0deg);
    transform-style: preserve-3d;
}

.flip-box-header {
    display: flex;
    justify-content: center;
}

.flip-back-col {
    background-color: var(--surface);
}

.flip-box:hover .flip-box-front {
    transform: rotateY(-180deg);
    transform-style: preserve-3d;
}

.flip-box-back {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    transform: rotateY(180deg);
    transform-style: preserve-3d;
}

.flip-box:hover .flip-box-back {
    transform: rotateY(0deg);
    transform-style: preserve-3d;
}

.flip-box .inner-front {
    position: absolute;
    left: 0;
    width: 100%;
    padding: 60px;
    outline: 1px solid transparent;
    perspective: inherit;
    z-index: 2;
    transform: translateY(-50%) translateZ(60px) scale(.94);
    top: 70%;
}

.flip-box .inner-front-about {
    position: absolute;
    left: 0;
    width: 100%;
    padding: 60px;
    outline: 1px solid transparent;
    perspective: inherit;
    z-index: 2;
    transform: translateY(-50%) translateZ(60px) scale(.94);
    top: 85%;
}

.flip-box .inner-back {
    position: absolute;
    left: 0;
    width: 100%;
    padding: 40px;
    outline: 1px solid transparent;
    perspective: inherit;
    z-index: 2;
    transform: translateY(-50%) translateZ(60px) scale(.94);
    top: 50%;
}

.flip-box .inner-back h2 {
    color: var(--ink);
    font-weight: 700;
    margin-bottom: 4px;
}

.flip-box .inner-back h4 {
    color: var(--red);
    font-weight: 400;
    font-size: 0.95rem;
    letter-spacing: 0.02em;
}

.flip-box .inner-back p {
    margin-top: 12px;
    font-size: 0.9rem;
    color: var(--ink-muted);
    line-height: 1.7;
}

.flip-box .inner-front h2 {
    font-weight: 700;
    color: white;
}

/* ─── Contact Form ───────────────────────────────────────── */
.form-area {
    padding-top: 7%;
    padding-bottom: 10%;
}

.row.single-form {
    box-shadow: var(--shadow-lg);
    border-radius: var(--radius-lg);
    overflow: hidden;
}

.contact-left {
    background: linear-gradient(145deg, var(--red), var(--red-dark));
    height: 100%;
    padding: 10% 10%;
    border-radius: 0;
}

.contact-left h2 {
    color: white;
    font-weight: 700;
}

.contact-left p {
    color: rgba(255, 255, 255, 0.85);
    line-height: 1.7;
}

.contact-right {
    padding: 5% 5%;
    position: relative;
    background: var(--surface);
}

.recaptcha-notice {
    margin-top: 12px;
    font-size: 0.75rem;
    color: var(--ink-muted, #888);
    line-height: 1.4;
}

.recaptcha-notice a {
    color: inherit;
    text-decoration: underline;
}

.grecaptcha-badge {
    visibility: hidden !important;
    opacity: 0 !important;
}

/* ─── Courses / Accordion ────────────────────────────────── */
.containerKurse {
    width: 60vw;
    margin: auto;
    padding-top: 3%;
    display: flex;
    justify-content: center;
    flex-direction: column;
    align-items: center;
}

.nav-link {
    color: var(--red);
    font-weight: 600;
}

.nav-link:hover {
    color: var(--red-dark);
}

.accordion-button {
    color: var(--red);
    font-weight: 600;
    width: 60vw;
    border-radius: var(--radius-sm) !important;
    transition: background 0.2s var(--ease), color 0.2s var(--ease);
}

.accordion-button:not(.collapsed) {
    color: white;
    font-weight: 700;
    background: linear-gradient(135deg, var(--red), var(--red-dark));
    box-shadow: var(--shadow-red);
    width: 100%;
}

.accordion-button:focus {
    outline: none;
    box-shadow: 0 0 0 3px var(--red-glow);
}

.accordion-button:hover {
    color: white;
    font-weight: 700;
    background: linear-gradient(135deg, var(--red), var(--red-dark));
    width: 100%;
}

/* ─── Carousel dot connector ────────────────────────────── */
.caption-dot {
    opacity: 0.85;
    font-size: 0.85em;
    vertical-align: middle;
    letter-spacing: 0;
}

/* ─── Middle Strip ───────────────────────────────────────── */
.middle-strip {
    width: 100%;
    height: 22vh;
    overflow: hidden;
    position: relative;
}

.middle-strip::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(
        to right,
        rgba(216, 46, 38, 0.25),
        transparent 40%,
        transparent 60%,
        rgba(216, 46, 38, 0.25)
    );
    z-index: 1;
    pointer-events: none;
}

.middle-strip img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center;
    display: block;
}

/* ─── Footer ─────────────────────────────────────────────── */
footer {
    background: var(--surface-2);
    border-top: 1px solid var(--border);
    height: auto;
    padding: 40px 24px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 10px;
    margin-top: 5%;
}

.footer-social {
    display: flex;
    gap: 14px;
    margin-bottom: 4px;
}

.footer-social-link {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 42px;
    height: 42px;
    border-radius: 50%;
    background: var(--red-subtle);
    color: var(--red);
    border: 1px solid rgba(216, 46, 38, 0.15);
    transition: background 0.2s var(--ease), color 0.2s var(--ease), transform 0.2s var(--ease-spring);
    text-decoration: none;
}

.footer-social-link:hover {
    background: var(--red);
    color: white;
    transform: translateY(-2px);
}

.footer-email {
    color: var(--red);
    font-weight: 600;
    text-underline-offset: 3px;
    transition: opacity 0.2s;
    text-decoration: underline;
}

.footer-email:hover {
    opacity: 0.75;
}

footer p {
    font-size: 0.82rem;
    color: var(--ink-muted);
}

/* ─── Social Hub (Blog-Seite) ────────────────────────────── */
.social-hub {
    display: flex;
    gap: 28px;
    justify-content: center;
    flex-wrap: wrap;
    padding: 40px 24px 60px;
    max-width: 800px;
    margin: 0 auto;
}

.social-card {
    display: flex;
    align-items: flex-start;
    gap: 20px;
    flex: 1;
    min-width: 260px;
    max-width: 360px;
    padding: 28px 26px;
    border-radius: var(--radius-lg);
    text-decoration: none;
    border: 1px solid var(--border);
    box-shadow: var(--shadow-sm);
    background: var(--surface);
    transition: transform 0.22s var(--ease-spring), box-shadow 0.22s var(--ease);
}

.social-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

.social-card__icon {
    flex-shrink: 0;
    width: 56px;
    height: 56px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
}

.social-card--linkedin .social-card__icon {
    background: #e8f0fb;
    color: #0a66c2;
}

.social-card--instagram .social-card__icon {
    background: #fde8f0;
    color: #c13584;
}

.social-card__body {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.social-card__platform {
    font-weight: 700;
    font-size: 1rem;
    color: var(--ink);
    letter-spacing: -0.01em;
}

.social-card__desc {
    font-size: 0.875rem;
    color: var(--ink-muted);
    line-height: 1.6;
    margin: 0;
}

.social-card__cta {
    font-size: 0.82rem;
    font-weight: 600;
    margin-top: 4px;
}

.social-card--linkedin .social-card__cta  { color: #0a66c2; }
.social-card--instagram .social-card__cta { color: #c13584; }

/* ─── SRC Logo ───────────────────────────────────────────── */
.LogoSRC {
    display: inline-block;
}

.LogoSRC img {
    max-height: 120px;
    width: auto;
}

/* ─── Utility ────────────────────────────────────────────── */
.color-white {
    color: white;
}

.zert-link {
    color: var(--red);
    font-weight: 600;
    text-decoration: underline;
    text-underline-offset: 3px;
}

.logo_about {
    height: 200px;
}

.team-photo-div {
    position: relative;
    height: calc(100vw * 0.35);
    min-height: 200px;
    display: flex;
}

/* Section accent dividers */
.section-label {
    display: inline-block;
    font-size: 0.7rem;
    font-weight: 700;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--red);
    margin-bottom: 12px;
}

/* Subtle red-tinted card backgrounds */
.card-red-hint {
    background: var(--red-subtle);
    border: 1px solid rgba(216, 46, 38, 0.12);
    border-radius: var(--radius-md);
}

/* ─── Nav Dropdown ───────────────────────────────────────── */
.nav-has-dropdown {
    position: relative;
}

.nav-has-dropdown > a::after {
    content: '';
    display: inline-block;
    width: 6px;
    height: 6px;
    border-right: 1.5px solid currentColor;
    border-bottom: 1.5px solid currentColor;
    transform: rotate(45deg) translateY(-2px);
    margin-left: 6px;
    transition: transform 0.2s var(--ease);
}

.nav-has-dropdown:hover > a::after {
    transform: rotate(-135deg) translateY(-2px);
}

.nav-dropdown {
    visibility: hidden;
    opacity: 0;
    pointer-events: none;
    position: absolute;
    top: calc(100% + 6px);
    left: 0;
    width: max-content;
    min-width: 160px;
    background: rgba(255, 255, 255, 0.96);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-md);
    padding: 6px 2px;
    list-style: none;
    z-index: 1000;
    transition: opacity 0.15s var(--ease), visibility 0s 0.5s;
}

.nav-dropdown::before {
    content: '';
    position: absolute;
    top: -10px;
    left: 0;
    right: 0;
    height: 10px;
}

.nav-has-dropdown:hover .nav-dropdown {
    visibility: visible;
    opacity: 1;
    pointer-events: auto;
    transition: opacity 0.15s var(--ease), visibility 0s 0s;
}

.nav-dropdown li {
    width: 100%;
}

.nav-dropdown li a {
    display: block;
    padding: 5px 14px;
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--ink);
    white-space: nowrap;
    transition: background 0.15s var(--ease), color 0.15s var(--ease);
}

.nav-dropdown li a:hover {
    background: var(--red-subtle);
    color: var(--red);
}

/* Mobile sidebar accordion */
.sidebar-expandable-row {
    display: flex;
    align-items: center;
    width: 100%;
}

.sidebar-expandable-row > a {
    flex: 1;
}

.sidebar-chevron {
    background: none;
    border: none;
    cursor: pointer;
    padding: 10px 16px;
    color: var(--ink-muted);
    display: flex;
    align-items: center;
    transition: color 0.2s var(--ease);
}

.sidebar-chevron svg {
    transition: transform 0.25s var(--ease);
}

.sidebar-expandable.open .sidebar-chevron {
    color: var(--red);
}

.sidebar-expandable.open .sidebar-chevron svg {
    transform: rotate(180deg);
}

.sidebar-submenu {
    list-style: none;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.28s var(--ease);
    padding: 0;
}

.sidebar-expandable.open .sidebar-submenu {
    max-height: 200px;
    padding-top: 4px;
}

.sidebar-expandable.open {
    margin-bottom: 16px;
}

.sidebar-submenu li a {
    padding-left: 44px !important;
}

/* ─── Responsive ─────────────────────────────────────────── */
@media (max-width: 767px) {
    .hideOnMobile {
        display: none;
    }

    .menuButton {
        display: block;
    }

    nav ul {
        padding-right: 0;
    }

    .containerKurse {
        width: 90vw;
    }

    .accordion-button {
        width: 90vw;
    }

    body {
        padding-top: 70px;
    }
}

@media (max-width: 490px) {
    .sidebar {
        width: 100vw;
    }
}