* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}


/* =====================================================
   BASIS
   ===================================================== */

body {
    background-color: var(--color-background);
    color: var(--color-text);

    font-family:
        Inter,
        system-ui,
        -apple-system,
        BlinkMacSystemFont,
        "Segoe UI",
        sans-serif;

    line-height: 1.6;
}


/* =====================================================
   NAVIGATION
   ===================================================== */

nav {
    margin-top: 30px;
}

nav a {
    color: var(--color-primary);
    text-decoration: none;

    margin: 0 10px;

    transition: color var(--transition-fast);
}

nav a:hover {
    color: var(--color-primary-hover);
}


/* =====================================================
   MAIN / SECTIONS
   ===================================================== */

main {
    max-width: 1000px;
    margin: 0 auto;

    padding: 60px 20px;
}

section {
    margin-bottom: 80px;
    padding: 30px;

    background-color: var(--color-surface);
    border-radius: var(--radius-lg);
}

section h2 {
    margin-bottom: 20px;

    font-size: 2rem;
    color: var(--color-primary);
}

section p {
    color: var(--color-text-muted);
}


/* =====================================================
   HEADER
   ===================================================== */

header {
    min-height: 100vh;

    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;

    text-align: center;

    padding: 40px 20px;
}

header h1 {
    font-size: 5rem;
    color: var(--color-primary);
}

header p {
    max-width: 650px;
    margin-top: 10px;

    font-size: 1.2rem;
    color: var(--color-text-muted);
}

header article {
    background-color: var(--color-surface-soft);

    padding: 20px;
    margin-top: 10px;
    margin-bottom: 10px;

    border-radius: var(--radius-md);
    border-left: 4px solid var(--color-primary);
}

header h3 {
    margin-bottom: 10px;

    color: var(--color-text);
    font-size: 1.3rem;
}


/* =====================================================
   LINKS
   ===================================================== */

#links ul {
    list-style: none;

    display: flex;
    align-items: center;
    flex-direction: row;
    gap: 10px;

    background-color: var(--color-surface-soft);

    padding: 10px 15px;
    margin-bottom: 10px;

    border-radius: var(--radius-md);
}

#links a {
    display: inline-block;

    margin-top: 15px;
    padding: 10px 16px;

    background-color: var(--color-primary);
    color: var(--color-on-primary);

    text-decoration: none;
    border-radius: var(--radius-md);

    transition:
        transform var(--transition-fast),
        box-shadow var(--transition-fast),
        background-color var(--transition-fast);
}

#links a:hover {
    background-color: var(--color-primary-hover);

    transform: translateY(-2px);
    box-shadow: 0 6px 15px rgba(0, 0, 0, 0.35);
}

#links a:active {
    background-color: var(--color-primary-active);
}

#links h3 {
    margin-bottom: 10px;

    color: var(--color-text);
    font-size: 1.3rem;
}


/* =====================================================
   SKILLS
   ===================================================== */

#skills ul {
    list-style: none;
}


/* Skillname + Status */

.skill-header {
    display: flex;
    justify-content: space-between;
    align-items: center;

    width: 100%;

    padding: 0;
    border: 0;

    background: transparent;
    color: inherit;
    font: inherit;

    text-align: left;
    cursor: pointer;
}

.skill-header span {
    font-size: 1.1rem;
    font-weight: bold;
}

.skill-header small {
    background-color: var(--color-surface);

    padding: 5px 10px;

    border-radius: var(--radius-sm);

    color: var(--color-text-muted);
}

#skills .skill-header[aria-expanded="true"] + p {
    max-height: 150px;

    opacity: 1;

    margin-top: 15px;

    transform: translateY(0);
}

#skills li {
    background-color: var(--color-surface-soft);

    margin-bottom: 10px;
    padding: 15px 20px;

    border-radius: var(--radius-md);
    border-left: 4px solid var(--color-primary);
}


/* Beschreibung eingeklappt */

#skills li p {
    max-height: 0;

    opacity: 0;
    overflow: hidden;

    margin: 0;

    transform: translateY(-5px);

    transition:
        max-height var(--transition-normal),
        opacity var(--transition-normal),
        margin var(--transition-normal),
        transform var(--transition-normal);
}


/* =====================================================
   PROJEKTE
   ===================================================== */

#projects article {
    background-color: var(--color-surface-soft);

    padding: 20px;

    border-radius: var(--radius-md);
    border-left: 4px solid var(--color-primary);

    transition:
        transform var(--transition-fast),
        box-shadow var(--transition-fast);
}

#projects article:hover {
    transform: translateY(-5px);

    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.35);
}

#projects article + article {
    margin-top: 15px;
}

#projects h3 {
    margin-bottom: 10px;

    color: var(--color-text);
    font-size: 1.3rem;
}


/* =====================================================
   ZERTIFIKATE
   ===================================================== */

#certificates article {
    background-color: var(--color-surface-soft);

    padding: 20px;

    border-radius: var(--radius-md);
    border-left: 4px solid var(--color-primary);

    transition:
        transform var(--transition-fast),
        box-shadow var(--transition-fast);
}

#certificates article:hover {
    transform: translateY(-5px);

    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.35);
}

#certificates a {
    display: inline-block;

    margin-top: 15px;
    padding: 10px 16px;

    background-color: var(--color-primary);
    color: var(--color-on-primary);

    text-decoration: none;
    border-radius: var(--radius-md);

    transition:
        transform var(--transition-fast),
        box-shadow var(--transition-fast),
        background-color var(--transition-fast);
}

#certificates a:hover {
    background-color: var(--color-primary-hover);

    transform: translateY(-2px);
    box-shadow: 0 6px 15px rgba(0, 0, 0, 0.35);
}

#certificates a:active {
    background-color: var(--color-primary-active);
}

#certificates article + article {
    margin-top: 15px;
}

#certificates h3 {
    margin-bottom: 10px;

    color: var(--color-text);
    font-size: 1.3rem;
}