/* === CSS Variables === */
:root {
    --color-alkalimetall: #ff6b6b;
    --color-erdalkalimetall: #ffa94d;
    --color-uebergangsmetall: #ffd43b;
    --color-metall: #69db7c;
    --color-halbmetall: #38d9a9;
    --color-nichtmetall: #4dabf7;
    --color-halogen: #9775fa;
    --color-edelgas: #da77f2;
    --color-lanthanoid: #e599f7;
    --color-actinoid: #faa2c1;

    --bg: #1a1a2e;
    --bg-light: #16213e;
    --text: #eee;
    --text-muted: #aaa;
    --modal-bg: #0f3460;
    --cell-bg: rgba(255,255,255,0.06);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, sans-serif;
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
    padding: 1rem;
}

/* === Header === */
header {
    text-align: center;
    padding: 1rem 0 1.5rem;
}

header h1 {
    font-size: 1.8rem;
    font-weight: 300;
    letter-spacing: 0.05em;
}

/* === Periodic Table Grid === */
.periodic-table {
    display: grid;
    grid-template-columns: repeat(18, 1fr);
    grid-template-rows: repeat(10, auto);
    gap: clamp(2px, 0.3vw, 6px);
    margin: 0 auto;
    padding: 0 0.5rem;
}

/* === Element Cell === */
.element-cell {
    aspect-ratio: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    border-radius: 4px;
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    padding: 2px;
    position: relative;
    min-width: 0;
    background: var(--cell-bg);
    border: 2px solid transparent;
    font-size: clamp(0.7rem, 1.6vw, 1.6rem);
}

.element-cell:hover,
.element-cell:focus-visible {
    transform: scale(1.15);
    z-index: 10;
    box-shadow: 0 4px 20px rgba(0,0,0,0.5);
}

.element-cell:focus-visible {
    outline: 2px solid #fff;
    outline-offset: 2px;
}

.element-cell .ordnungszahl {
    font-size: 0.65em;
    opacity: 0.8;
    line-height: 1;
}

.element-cell .symbol {
    font-size: 1.2em;
    font-weight: 700;
    line-height: 1.2;
}

.element-cell .name {
    font-size: 0.55em;
    opacity: 0.8;
    line-height: 1;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    max-width: 100%;
}

.element-cell .masse {
    font-size: 0.5em;
    opacity: 0.6;
    line-height: 1;
}

/* === Category Colors (border-color) === */
.element-cell.alkalimetall { border-color: var(--color-alkalimetall); background: rgba(255,107,107,0.15); }
.element-cell.erdalkalimetall { border-color: var(--color-erdalkalimetall); background: rgba(255,169,77,0.15); }
.element-cell.uebergangsmetall { border-color: var(--color-uebergangsmetall); background: rgba(255,212,59,0.15); }
.element-cell.metall { border-color: var(--color-metall); background: rgba(105,219,124,0.15); }
.element-cell.halbmetall { border-color: var(--color-halbmetall); background: rgba(56,217,169,0.15); }
.element-cell.nichtmetall { border-color: var(--color-nichtmetall); background: rgba(77,171,247,0.15); }
.element-cell.halogen { border-color: var(--color-halogen); background: rgba(151,117,250,0.15); }
.element-cell.edelgas { border-color: var(--color-edelgas); background: rgba(218,119,242,0.15); }
.element-cell.lanthanoid { border-color: var(--color-lanthanoid); background: rgba(229,153,247,0.15); }
.element-cell.actinoid { border-color: var(--color-actinoid); background: rgba(250,162,193,0.15); }

/* === Marker Cells (57-71, 89-103) === */
.marker-cell {
    aspect-ratio: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 4px;
    font-size: clamp(0.55rem, 1vw, 1.1rem);
    font-weight: 700;
    min-width: 0;
    letter-spacing: -0.02em;
}

.marker-cell.lanthanoid-marker {
    border: 2px dashed var(--color-lanthanoid);
    color: var(--color-lanthanoid);
}

.marker-cell.actinoid-marker {
    border: 2px dashed var(--color-actinoid);
    color: var(--color-actinoid);
}

/* === Spacer Row 8 === */
.spacer-row {
    grid-column: 1 / -1;
    grid-row: 8;
    height: 1.5rem;
}

/* === Legend === */
.legend {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 0.8rem;
    margin: 1.5rem auto 1rem;
    padding: 1rem;
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    font-size: 0.8rem;
}

.legend-color {
    width: 14px;
    height: 14px;
    border-radius: 3px;
    flex-shrink: 0;
}

/* === Footnote === */
.footnote {
    text-align: center;
    font-size: 0.85rem;
    color: var(--text-muted);
    margin: 0 auto 1.5rem;
}

/* === Modal Overlay === */
.modal-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.7);
    z-index: 1000;
    justify-content: center;
    align-items: center;
    padding: 1rem;
    overflow-y: auto;
}

.modal-overlay.active {
    display: flex;
}

.modal-content {
    background: var(--modal-bg);
    border-radius: 12px;
    max-width: 600px;
    width: 100%;
    max-height: 90vh;
    overflow-y: auto;
    padding: 2rem;
    position: relative;
    box-shadow: 0 20px 60px rgba(0,0,0,0.5);
    animation: modalIn 0.25s ease;
}

@keyframes modalIn {
    from { opacity: 0; transform: translateY(20px) scale(0.95); }
    to { opacity: 1; transform: translateY(0) scale(1); }
}

.modal-close {
    position: absolute;
    top: 0.8rem;
    right: 1rem;
    background: none;
    border: none;
    color: var(--text);
    font-size: 2rem;
    cursor: pointer;
    line-height: 1;
    opacity: 0.7;
    transition: opacity 0.2s;
}

.modal-close:hover { opacity: 1; }

/* Modal Header */
.modal-header {
    display: flex;
    align-items: center;
    gap: 1.5rem;
    margin-bottom: 1.5rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid rgba(255,255,255,0.1);
}

.modal-symbol {
    font-size: 4rem;
    font-weight: 700;
    min-width: 5rem;
    height: 5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 10px;
    background: rgba(255,255,255,0.08);
}

.modal-title h2 {
    font-size: 1.6rem;
    margin-bottom: 0.3rem;
}

.modal-ordnungszahl,
.modal-masse {
    font-size: 0.9rem;
    color: var(--text-muted);
}

.modal-kategorie-badge {
    display: inline-block;
    padding: 0.2rem 0.6rem;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 600;
    margin-top: 0.4rem;
    text-transform: capitalize;
}

/* Modal Sections */
.modal-section {
    margin-bottom: 1.2rem;
}

.modal-section h3 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 0.6rem;
    padding-bottom: 0.3rem;
    border-bottom: 1px solid rgba(255,255,255,0.08);
    color: var(--text-muted);
}

.modal-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: 0.5rem;
}

.modal-prop {
    display: flex;
    flex-direction: column;
    padding: 0.4rem 0;
}

.modal-prop .label {
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-bottom: 0.15rem;
}

.modal-prop .value {
    font-size: 0.95rem;
    font-weight: 500;
}

.modal-list {
    list-style: none;
    padding: 0;
}

.modal-list li {
    padding: 0.3rem 0;
    font-size: 0.9rem;
}

.modal-list li::before {
    content: "• ";
    opacity: 0.5;
}

.modal-beschreibung {
    margin-top: 0.6rem;
    font-size: 0.9rem;
    line-height: 1.5;
    color: var(--text-muted);
}

/* === Responsive === */

/* Breakpoint 1200px */
@media (max-width: 1200px) {
    .periodic-table {
        gap: 2px;
    }

    .element-cell .symbol {
        font-size: 1em;
    }

    .element-cell .name {
        font-size: 0.45em;
    }
}

/* Breakpoint 768px */
@media (max-width: 768px) {
    body {
        padding: 0.5rem;
    }

    header h1 {
        font-size: 1.3rem;
    }

    .periodic-table {
        gap: 1px;
    }

    .element-cell {
        padding: 1px;
        border-width: 1px;
    }

    .element-cell .ordnungszahl {
        font-size: 0.45em;
    }

    .element-cell .symbol {
        font-size: 0.85em;
    }

    .element-cell .name,
    .element-cell .masse {
        display: none;
    }

    .marker-cell {
        font-size: 0.5em;
    }

    .modal-content {
        padding: 1.2rem;
        max-height: 95vh;
    }

    .modal-symbol {
        font-size: 2.5rem;
        min-width: 3.5rem;
        height: 3.5rem;
    }

    .modal-title h2 {
        font-size: 1.2rem;
    }

    .modal-grid {
        grid-template-columns: 1fr 1fr;
    }
}

/* Breakpoint 480px */
@media (max-width: 480px) {
    header h1 {
        font-size: 1rem;
    }

    .element-cell .ordnungszahl {
        display: none;
    }

    .element-cell .symbol {
        font-size: 0.7em;
    }

    .element-cell {
        aspect-ratio: auto;
        min-height: 24px;
    }

    .modal-content {
        width: 100%;
        border-radius: 8px;
        padding: 1rem;
    }

    .modal-header {
        flex-direction: column;
        text-align: center;
        gap: 0.8rem;
    }

    .modal-grid {
        grid-template-columns: 1fr;
    }

    .legend {
        gap: 0.4rem;
    }

    .legend-item {
        font-size: 0.7rem;
    }
}