/* ==========================================================================
   Stud.App 2.0 — studapp2.de Test-Flight-Webseite
   Design-Tokens übernommen aus DESIGN_LANGUAGE.md & studapp2.de-onepager.html
   Brand-Akzent Campus Indigo · 4-Punkt-Spacing · Aurora-Gradient
   ========================================================================== */

:root {
    --accent       : #5D3DC0;
    --accent-strong: #4928A3;
    --accent-soft  : #EFEBFB;
    --on-accent    : #ffffff;

    --course-1: #2ECDBE;   /* Türkis */
    --course-2: #2ECC71;   /* Grün   */
    --course-3: #F5B041;   /* Gelb-Orange */
    --course-5: #E91E63;   /* Pink   */

    --bg          : #FAFAFA;
    --bg-elevated : #FFFFFF;
    --bg-tint     : #F2F2F4;
    --line        : #E6E6EA;

    --text        : #1C1C1E;
    --text-2      : #4A4A52;
    --text-3      : #6B6B73;

    --success: #16A34A;
    --warning: #F59E0B;
    --danger : #DC2626;

    --aurora: linear-gradient(135deg,
        var(--course-1)   0%,
        var(--course-2)  25%,
        var(--accent)    50%,
        var(--course-5)  75%,
        var(--course-3) 100%);

    --aurora-soft: linear-gradient(135deg,
        rgba(46, 205, 190, 0.18)   0%,
        rgba(46, 204, 113, 0.13)  25%,
        rgba(93,  61, 192, 0.18)  50%,
        rgba(233, 30,  99, 0.13)  75%,
        rgba(245, 176, 65,  0.16) 100%);

    --r-button: 10px;
    --r-card  : 14px;
    --r-sheet : 18px;
    --r-modal : 24px;

    --sp-xxs: 2px;  --sp-xs: 4px;   --sp-s : 8px;   --sp-m : 12px;
    --sp-l : 16px;  --sp-xl: 24px;  --sp-xxl: 32px; --sp-xxxl: 48px;

    --shadow-low : 0 1px 2px rgba(28, 28, 32, 0.04), 0 8px 24px rgba(28, 28, 32, 0.06);
    --shadow-mid : 0 4px 16px rgba(28, 28, 32, 0.10);

    --font-rounded: ui-rounded, "SF Pro Rounded", system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    --font-text   : -apple-system, BlinkMacSystemFont, "SF Pro Text", system-ui, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    --font-mono   : ui-monospace, "SF Mono", Menlo, Consolas, monospace;
}

@media (prefers-color-scheme: dark) {
    :root {
        --accent       : #7D5EE8;
        --accent-strong: #9F84FF;
        --accent-soft  : #1E1735;
        --on-accent    : #ffffff;

        --bg          : #0E0E12;
        --bg-elevated : #18181E;
        --bg-tint     : #1F1F26;
        --line        : #2A2A33;

        --text  : #F2F2F5;
        --text-2: #B7B7C0;
        --text-3: #8B8B95;

        --aurora-soft: linear-gradient(135deg,
            rgba(54,  224, 207, 0.14)  0%,
            rgba(75,  223, 136, 0.10) 25%,
            rgba(125, 94,  232, 0.22) 50%,
            rgba(255, 71,  133, 0.12) 75%,
            rgba(255, 194, 98,  0.13) 100%);

        --shadow-low : 0 0 0 0.5px rgba(255, 255, 255, 0.06);
        --shadow-mid : 0 0 0 0.5px rgba(255, 255, 255, 0.10);
    }
}

/* ==========================================================================
   Reset + Typo-Baseline
   ========================================================================== */
*, *::before, *::after { box-sizing: border-box; }

html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; }
    *, *::before, *::after {
        animation-duration: 0.001ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.001ms !important;
    }
}

body {
    margin: 0;
    font-family: var(--font-text);
    color: var(--text);
    background: var(--bg);
    line-height: 1.55;
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
}

h1, h2, h3, h4 {
    font-family: var(--font-rounded);
    letter-spacing: -0.02em;
    line-height: 1.2;
    margin: 0 0 var(--sp-m) 0;
    color: var(--text);
}

h1 { font-size: clamp(2rem, 4.6vw + 1rem, 3.4rem); font-weight: 700; line-height: 1.15; }
h2 { font-size: clamp(1.5rem, 2vw + 1rem, 2.2rem); font-weight: 700; }
h3 { font-size: 1.15rem; font-weight: 600; }
h4 { font-size: 1rem; font-weight: 600; }

p { margin: 0 0 var(--sp-m) 0; color: var(--text-2); }
ul, ol { margin: 0 0 var(--sp-m) 0; padding-left: var(--sp-xl); color: var(--text-2); }
li { margin-bottom: var(--sp-xs); }

a { color: var(--accent); text-decoration: none; }
a:hover, a:focus-visible { text-decoration: underline; }

:focus-visible {
    outline: 3px solid var(--accent);
    outline-offset: 2px;
    border-radius: 4px;
}

/* Skip-Link für Tastatur-Navigation */
.skip {
    position: absolute; left: -10000px; top: var(--sp-m); z-index: 100;
    background: var(--accent); color: var(--on-accent);
    padding: var(--sp-s) var(--sp-l); border-radius: var(--r-button);
    font-weight: 600;
}
.skip:focus { left: var(--sp-m); }

/* ==========================================================================
   Layout-Container
   ========================================================================== */
.container {
    width: 100%;
    max-width: 960px;
    margin: 0 auto;
    padding: 0 var(--sp-l);
}
.container.narrow { max-width: 720px; }

section { padding: var(--sp-xxxl) 0; }
@media (min-width: 720px) { section { padding: 72px 0; } }

/* ==========================================================================
   Top-Bar
   ========================================================================== */
.topbar {
    position: sticky; top: 0; z-index: 50;
    background: color-mix(in srgb, var(--bg) 85%, transparent);
    backdrop-filter: saturate(180%) blur(12px);
    -webkit-backdrop-filter: saturate(180%) blur(12px);
    border-bottom: 1px solid var(--line);
}
.topbar-inner {
    display: flex; align-items: center; gap: var(--sp-l);
    padding: var(--sp-m) var(--sp-l);
    max-width: 960px; margin: 0 auto;
}
.brand {
    display: inline-flex; align-items: center; gap: var(--sp-s);
    font-family: var(--font-rounded); font-weight: 700;
    color: var(--text); text-decoration: none;
    font-size: 1.05rem;
}
.brand:hover { text-decoration: none; }
.brand-mark {
    width: 28px; height: 28px; border-radius: 8px;
    background: var(--aurora);
    box-shadow: var(--shadow-low);
    flex: 0 0 28px;
}

.nav { margin-left: auto; display: none; gap: var(--sp-l); }
@media (min-width: 720px) { .nav { display: inline-flex; } }
.nav a { color: var(--text-2); font-weight: 500; font-size: 0.95rem; }
.nav a:hover { color: var(--text); text-decoration: none; }
.nav a[aria-current="page"] { color: var(--accent); }

/* ==========================================================================
   Buttons
   ========================================================================== */
.btn {
    display: inline-flex; align-items: center; justify-content: center;
    gap: var(--sp-s);
    min-height: 44px; padding: 10px var(--sp-xl);
    border-radius: var(--r-button);
    font-family: var(--font-text); font-weight: 600; font-size: 1rem;
    border: 1px solid transparent; cursor: pointer;
    transition: transform 180ms ease, box-shadow 180ms ease, background 180ms ease;
    white-space: nowrap; line-height: 1;
    text-align: center;
}
.btn-primary {
    background: var(--accent); color: var(--on-accent);
    box-shadow: var(--shadow-low);
}
.btn-primary:hover {
    background: var(--accent-strong); color: var(--on-accent);
    text-decoration: none; transform: translateY(-1px); box-shadow: var(--shadow-mid);
}
.btn-secondary {
    background: transparent; color: var(--accent);
    border-color: var(--accent);
}
.btn-secondary:hover { background: var(--accent-soft); text-decoration: none; }
.btn-row { display: flex; flex-wrap: wrap; gap: var(--sp-m); }

.btn svg { width: 18px; height: 18px; fill: currentColor; flex: 0 0 18px; }

/* ==========================================================================
   Hero
   ========================================================================== */
.hero {
    position: relative; overflow: hidden;
    padding-top: var(--sp-xxxl); padding-bottom: var(--sp-xxxl);
}
.hero::before {
    content: ""; position: absolute; inset: -10% -10% auto -10%;
    height: 70%;
    background: var(--aurora-soft);
    filter: blur(40px); opacity: 0.9;
    pointer-events: none; z-index: 0;
}
.hero-inner { position: relative; z-index: 1; }

.eyebrow {
    display: inline-flex; align-items: center; gap: var(--sp-s);
    padding: 6px var(--sp-m);
    background: var(--bg-elevated);
    border: 1px solid var(--line);
    border-radius: 999px;
    font-size: 0.85rem; color: var(--text-2);
    margin-bottom: var(--sp-l);
}
.eyebrow .dot {
    width: 8px; height: 8px; border-radius: 50%;
    background: var(--aurora);
    flex: 0 0 8px;
}

.hero h1 .accent {
    background: var(--aurora);
    -webkit-background-clip: text; background-clip: text;
    color: transparent;
}
.hero p.lead {
    font-size: clamp(1.05rem, 0.6vw + 1rem, 1.2rem);
    color: var(--text-2);
    max-width: 58ch;
    margin-bottom: var(--sp-xl);
}

.hero-meta {
    display: flex; flex-wrap: wrap; gap: var(--sp-m);
    margin-top: var(--sp-xl);
    font-size: 0.9rem; color: var(--text-3);
}
.hero-meta .sep { color: var(--line); }

/* ==========================================================================
   Section Heading
   ========================================================================== */
.section-head { max-width: 60ch; margin-bottom: var(--sp-xl); }
.section-head .kicker {
    display: inline-block;
    font-size: 0.8rem; font-weight: 600; letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--accent);
    margin-bottom: var(--sp-s);
}

/* ==========================================================================
   Testsysteme — zwei große Karten mit Versions-Badge
   ========================================================================== */
.testsystems {
    display: grid; gap: var(--sp-l);
    grid-template-columns: 1fr;
}
@media (min-width: 720px) {
    .testsystems { grid-template-columns: 1fr 1fr; }
}

.testsystem {
    background: var(--bg-elevated);
    border: 1px solid var(--line);
    border-radius: var(--r-card);
    padding: var(--sp-xl);
    display: flex; flex-direction: column; gap: var(--sp-m);
    position: relative; overflow: hidden;
}
.testsystem::before {
    content: ""; position: absolute; inset: 0;
    background: var(--aurora-soft); opacity: 0.35;
    pointer-events: none; z-index: 0;
}
.testsystem > * { position: relative; z-index: 1; }

.testsystem .ver {
    display: inline-flex; align-items: center; gap: var(--sp-xs);
    font-family: var(--font-rounded); font-weight: 700;
    font-size: 0.85rem; letter-spacing: 0.02em;
    padding: 4px var(--sp-s);
    border-radius: 999px;
    background: var(--accent-soft); color: var(--accent);
    align-self: flex-start;
}
.testsystem h3 { margin: 0; font-size: 1.25rem; }
.testsystem p { margin: 0; color: var(--text-2); font-size: 0.95rem; }

.testsystem .credentials {
    background: var(--bg-tint);
    border: 1px solid var(--line);
    border-radius: var(--r-button);
    padding: var(--sp-m);
    font-family: var(--font-mono);
    font-size: 0.85rem;
    color: var(--text-2);
    line-height: 1.6;
}
.testsystem .credentials strong {
    display: inline-block; min-width: 70px;
    color: var(--text); font-family: var(--font-text); font-weight: 600;
}
.testsystem .btn-row { margin-top: auto; padding-top: var(--sp-s); }

/* ==========================================================================
   Trust-Strip (Privacy by Design)
   ========================================================================== */
.trust {
    background: var(--bg-tint);
    border-top: 1px solid var(--line);
    border-bottom: 1px solid var(--line);
    position: relative; overflow: hidden;
}
.trust::before {
    content: ""; position: absolute; inset: 0;
    background: var(--aurora-soft); opacity: 0.5;
    pointer-events: none;
}
.trust .container { position: relative; }
.trust-grid {
    display: grid; gap: var(--sp-l);
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}
.trust-item {
    background: var(--bg-elevated);
    border: 1px solid var(--line);
    border-radius: var(--r-card);
    padding: var(--sp-l);
}
.trust-item h3 { font-size: 1rem; margin-bottom: var(--sp-xs); }
.trust-item p { margin: 0; font-size: 0.92rem; }

/* ==========================================================================
   FAQ
   ========================================================================== */
.faq { display: grid; gap: var(--sp-m); }
.faq details {
    background: var(--bg-elevated);
    border: 1px solid var(--line);
    border-radius: var(--r-card);
    padding: var(--sp-l) var(--sp-xl);
}
.faq summary {
    font-family: var(--font-rounded); font-weight: 600; font-size: 1.05rem;
    cursor: pointer; list-style: none;
    display: flex; justify-content: space-between; align-items: center; gap: var(--sp-m);
    color: var(--text);
    min-height: 28px;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after {
    content: "+"; font-weight: 400; font-size: 1.4rem; line-height: 1;
    color: var(--accent); transition: transform 200ms ease;
    flex: 0 0 auto;
}
.faq details[open] summary::after { content: "–"; }
.faq details p { margin: var(--sp-m) 0 0 0; color: var(--text-2); }
.faq details ul { margin: var(--sp-s) 0 0 0; color: var(--text-2); }

/* ==========================================================================
   Legal-Content (Impressum, Datenschutz, Support — Body-Layout)
   ========================================================================== */
.legal-page {
    padding-top: var(--sp-xl); padding-bottom: var(--sp-xxxl);
}
.legal-page .lead {
    color: var(--text-2); font-size: 1.05rem;
    margin-bottom: var(--sp-xl);
    max-width: 65ch;
}
.legal-page h2 {
    margin-top: var(--sp-xxl); margin-bottom: var(--sp-m);
    font-size: 1.5rem;
}
.legal-page h2:first-of-type { margin-top: 0; }
.legal-page h3 {
    margin-top: var(--sp-xl); margin-bottom: var(--sp-s);
    font-size: 1.1rem;
}
.legal-page p { max-width: 70ch; }
.legal-page ul, .legal-page ol { max-width: 70ch; }

.legal-page .placeholder {
    display: inline-block;
    background: color-mix(in srgb, var(--warning) 18%, transparent);
    color: var(--warning);
    border: 1px dashed var(--warning);
    border-radius: 4px;
    padding: 1px 6px;
    font-family: var(--font-mono); font-size: 0.85em;
    font-weight: 600;
}
@media (prefers-color-scheme: dark) {
    .legal-page .placeholder {
        background: color-mix(in srgb, var(--warning) 24%, transparent);
        color: #FFCB6B;
        border-color: #FFCB6B;
    }
}

.legal-page table {
    width: 100%;
    border-collapse: collapse;
    margin: var(--sp-m) 0 var(--sp-l);
    font-size: 0.94rem;
}
.legal-page th, .legal-page td {
    text-align: left;
    padding: var(--sp-s) var(--sp-m);
    border-bottom: 1px solid var(--line);
    vertical-align: top;
}
.legal-page th {
    font-family: var(--font-rounded); font-weight: 600;
    color: var(--text); background: var(--bg-tint);
}
.legal-page td { color: var(--text-2); }

.legal-page .note {
    background: var(--accent-soft);
    border-left: 3px solid var(--accent);
    border-radius: var(--r-button);
    padding: var(--sp-m) var(--sp-l);
    margin: var(--sp-l) 0;
    color: var(--text-2);
    font-size: 0.95rem;
}
.legal-page .note strong { color: var(--text); }

.legal-page .meta {
    color: var(--text-3); font-size: 0.9rem;
    margin-top: var(--sp-xxl);
    padding-top: var(--sp-l);
    border-top: 1px solid var(--line);
}

/* ==========================================================================
   Footer
   ========================================================================== */
footer {
    border-top: 1px solid var(--line);
    padding: var(--sp-xxl) 0;
    background: var(--bg-tint);
    font-size: 0.9rem; color: var(--text-3);
}
.footer-inner {
    display: grid; gap: var(--sp-l);
    grid-template-columns: 1fr;
}
@media (min-width: 720px) {
    .footer-inner { grid-template-columns: 2fr 1fr 1fr; }
}
.footer-brand p { margin-top: var(--sp-s); max-width: 38ch; color: var(--text-3); }
.footer-col h4 {
    font-family: var(--font-rounded); font-weight: 600; font-size: 0.95rem;
    color: var(--text); margin: 0 0 var(--sp-s) 0;
}
.footer-col ul { list-style: none; padding: 0; margin: 0; display: grid; gap: var(--sp-xs); }
.footer-col a { color: var(--text-2); }

.legal-strip {
    margin-top: var(--sp-xl);
    padding-top: var(--sp-l);
    border-top: 1px solid var(--line);
    display: flex; flex-wrap: wrap; gap: var(--sp-m);
    justify-content: space-between; align-items: center;
}

/* ==========================================================================
   Helpers
   ========================================================================== */
.visually-hidden {
    position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
    overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0;
}

/* noscript-Fallback für E-Mail-Adressen — wird nur sichtbar, wenn JavaScript
 * ausgeschaltet ist. Hält Stud.App § 5 TMG-konform erreichbar.
 */
.email-fallback {
    display: block;
    margin-top: var(--sp-s);
    padding: var(--sp-s) var(--sp-m);
    background: var(--bg-tint);
    border: 1px solid var(--line);
    border-radius: var(--r-button);
    font-size: 0.9rem;
    color: var(--text-2);
}
.email-fallback strong { color: var(--text); font-family: var(--font-mono); }