:root {
    /* Color Palette - Dark (Default) */
    --bg-color: #121212;
    --text-primary: #f1faee;
    --text-secondary: #a8dadc;
    --text-muted: rgba(255, 255, 255, 0.8);
    --text-dim: rgba(255, 255, 255, 0.65);

    --accent-blue: #457b9d;
    --accent-red: #e63946;

    --filter-bg: rgba(255, 255, 255, 0.06);
    --filter-border: rgba(255, 255, 255, 0.12);
    --filter-hover: rgba(255, 255, 255, 0.2);
    --filter-active-bg: rgba(255, 255, 255, 0.25);

    --header-border: rgba(255, 255, 255, 0.1);
    --nav-active-color: #f1faee;
    --nav-inactive-color: rgba(255, 255, 255, 0.4);

    --receipt-shadow: 0 10px 40px rgba(0,0,0,0.5);
    --card-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
    --receipt-border: 1px solid rgba(255, 255, 255, 0.05);

    /* Typography - Standardized */
    --font-main: 'Inter', -apple-system, sans-serif;
    --font-mono: 'JetBrains Mono', monospace;

    --fs-xs: 0.8rem;
    --fs-sm: 0.9rem;
    --fs-base: 1rem;
    --fs-md: 1.1rem;
    --fs-lg: 1.4rem;
    --fs-xl: 2.2rem;
    --fs-xxl: 3.2rem;

    /* Group Colors - Standardized */
    --color-rot: #e63946;
    --color-schwarz: #1d3557;
    --color-blau: #457b9d;

    /* Spacing - Standardized */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 2.5rem;
    --spacing-xxl: 3rem;
}

body.light-mode {
    --bg-color: #fcfcfc;
    --text-primary: #1d3557;
    --text-secondary: #457b9d;
    --text-muted: rgba(0, 0, 0, 0.75);
    --text-dim: rgba(0, 0, 0, 0.6);

    --filter-bg: rgba(0, 0, 0, 0.03);
    --filter-border: rgba(0, 0, 0, 0.08);
    --filter-hover: rgba(0, 0, 0, 0.06);
    --filter-active-bg: rgba(0, 0, 0, 0.1);

    --header-border: rgba(0, 0, 0, 0.08);
    --nav-active-color: #1d3557;
    --nav-inactive-color: rgba(0, 0, 0, 0.4);

    --receipt-shadow: 0 4px 15px rgba(0, 0, 0, 0.05);
    --receipt-border: 1px solid rgba(0, 0, 0, 0.05);

    --color-schwarz: #1d3557;
}

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

body {
    font-family: var(--font-main);
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.6;
    padding: var(--spacing-lg) var(--spacing-sm);
    transition: background-color 0.3s ease, color 0.3s ease;
    animation: fadeIn 0.4s ease-in-out;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.container {
    max-width: 1200px;
    margin: 0 auto;
}

/* Navigation */
.nav-toggle {
    display: flex;
    justify-content: center;
    margin-bottom: var(--spacing-lg);
    gap: var(--spacing-sm);
    position: relative;
    z-index: 10;
}

.nav-link {
    text-decoration: none;
    font-size: var(--fs-sm);
    font-weight: 700;
    color: var(--nav-inactive-color);
    padding: var(--spacing-xs) 1.2rem;
    transition: all 0.2s ease;
    border-bottom: 3px solid transparent;
    font-family: var(--font-mono);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.nav-link:hover { color: var(--text-primary); }
.nav-link.active {
    color: var(--nav-active-color);
    border-bottom-color: var(--accent-blue);
}

/* Page Header */
.page-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.page-header h1 {
    font-family: var(--font-mono);
    font-size: var(--fs-xxl);
    font-weight: 850;
    margin-bottom: var(--spacing-xs);
    letter-spacing: -0.02em;
}

.page-header p {
    font-size: var(--fs-md);
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

.brand-logo {
    font-family: var(--font-mono);
    font-weight: 900;
    letter-spacing: -0.04em;
    font-size: 2.6rem;
    color: var(--text-primary);
    text-transform: uppercase;
    text-decoration: none;
    position: absolute;
    top: 2.5rem;
    left: max(var(--spacing-md), 1.5rem);
    z-index: 1000;
    line-height: 1;
    transform: scaleY(1.15);
    transform-origin: top left;
}


/* Theme Toggle */
.theme-toggle {
    position: fixed;
    top: 1.5rem;
    right: 1.5rem;
    background: var(--filter-bg);
    border: 1px solid var(--filter-border);
    color: var(--text-primary);
    width: 40px;
    height: 40px;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    transition: all 0.3s ease;
    backdrop-filter: blur(8px);
}

.theme-toggle:hover {
    transform: scale(1.1);
    background: var(--filter-hover);
}

/* Common Components - Filter Bar */
.filter-bar {
    display: flex;
    justify-content: center;
    gap: var(--spacing-xs);
    margin-bottom: var(--spacing-xl);
    flex-wrap: wrap;
    opacity: 0.9;
}

.filter-btn {
    background: var(--filter-bg);
    border: 2px solid var(--filter-border);
    color: var(--text-muted);
    padding: var(--spacing-xs) 1.2rem;
    border-radius: 8px;
    cursor: pointer;
    font-size: var(--fs-sm);
    font-weight: 700;
    transition: all 0.2s ease;
    font-family: var(--font-mono);
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

.filter-btn:hover {
    background: var(--filter-hover);
    color: var(--text-primary);
    border-color: #555;
}

.filter-btn.active {
    background: var(--filter-active-bg);
    color: var(--text-primary);
    border-color: var(--text-dim);
}

/* Group-specific filter colors */
.filter-btn[data-group="ROT"].active,
.filter-btn[data-filter-group="ROT"].active,
.filter-btn.color-rot.active {
    border-color: var(--color-rot);
    color: var(--color-rot);
    background: rgba(230, 57, 70, 0.08);
}

.filter-btn[data-group="SCHWARZ"].active,
.filter-btn[data-filter-group="SCHWARZ"].active,
.filter-btn.color-schwarz.active {
    border-color: var(--color-schwarz);
    color: var(--color-schwarz);
    background: rgba(29, 53, 87, 0.08);
}

body.light-mode .filter-btn.color-schwarz.active {
    border-color: var(--color-schwarz);
    color: var(--color-schwarz);
}

body.dark-mode .filter-btn.color-schwarz.active {
    border-color: #f1faee;
    color: #f1faee;
    background: rgba(241, 250, 238, 0.08);
}

.filter-btn[data-group="BLAU"].active,
.filter-btn[data-filter-group="BLAU"].active,
.filter-btn.color-blau.active {
    border-color: var(--color-blau);
    color: var(--color-blau);
    background: rgba(69, 123, 157, 0.08);
}

/* Status filter colors */
.filter-btn.color-funded.active {
    border-color: #a8dadc;
    color: #a8dadc;
    background: rgba(168, 218, 220, 0.15);
}

.filter-btn.color-unfunded.active {
    border-color: #888;
    color: #888;
    background: rgba(136, 136, 136, 0.08);
}

/* Unified Intro & Dropdown Components */
.intro-section {
    max-width: 800px;
    margin: 0 auto var(--spacing-lg);
    text-align: center;
}

.intro-section p {
    margin-bottom: var(--spacing-sm);
    font-size: var(--fs-base);
    color: var(--text-dim);
    line-height: 1.7;
}

.intro-section p.philosophy {
    font-size: 1.05rem;
    color: var(--text-primary);
    display: inline; /* For merging */
}

.stats-line-compact {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    margin: 1.5rem 0 2rem;
    font-family: var(--font-mono);
    font-size: 0.85rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-weight: 700;
}

.stats-line-compact .label {
    opacity: 0.6;
}

.stats-line-compact .badges {
    display: flex;
    gap: 0.4rem;
}

.intro-section .highlight {
    color: var(--text-primary);
    font-weight: 700;
}

.intro-dropdown {
    max-width: 800px;
    margin: 0 auto var(--spacing-xl);
    text-align: left;
    background: rgba(255, 255, 255, 0.04);
    border: 1.5px solid rgba(255, 255, 255, 0.12);
    border-radius: 12px;
    transition: all 0.3s ease;
    backdrop-filter: blur(10px);
    overflow: hidden;
    list-style: none;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

body.light-mode .intro-dropdown {
    background: rgba(69, 123, 157, 0.04);
    border-color: rgba(69, 123, 157, 0.2);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
}

.intro-dropdown summary {
    padding: var(--spacing-md) var(--spacing-lg);
    cursor: pointer;
    font-weight: 700;
    font-size: var(--fs-md);
    color: var(--text-primary);
    display: flex;
    align-items: center;
    justify-content: space-between;
    list-style: none;
    transition: all 0.2s ease;
    font-family: var(--font-mono);
    letter-spacing: 0.02em;
    user-select: none;
}

.intro-dropdown summary::before {
    content: '💡';
    margin-right: var(--spacing-sm);
    font-size: var(--fs-md);
    opacity: 0.7;
}

.intro-dropdown summary::-webkit-details-marker { display: none; }
.intro-dropdown summary:hover {
    background: rgba(255, 255, 255, 0.07);
    color: var(--accent-blue);
}

body.light-mode .intro-dropdown summary:hover {
    background: rgba(69, 123, 157, 0.08);
    color: var(--accent-blue);
}

.intro-dropdown summary::after {
    content: '▼';
    font-family: var(--font-mono);
    font-size: var(--fs-sm);
    opacity: 0.6;
    transition: transform 0.3s ease, opacity 0.2s ease;
    margin-left: var(--spacing-sm);
}

.intro-dropdown summary:hover::after {
    opacity: 1;
}

.intro-dropdown[open] summary {
    background: rgba(255, 255, 255, 0.06);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

body.light-mode .intro-dropdown[open] summary {
    background: rgba(69, 123, 157, 0.06);
    border-bottom: 1px solid rgba(69, 123, 157, 0.15);
}

.intro-dropdown[open] summary::after {
    transform: rotate(180deg);
}

.intro-dropdown .dropdown-content {
    padding: var(--spacing-lg);
    font-size: var(--fs-base);
    color: var(--text-muted);
    line-height: 1.6;
    animation: slideDown 0.3s ease-out;
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.tech-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-md);
    margin: 0;
}

.tech-grid.single-column {
    grid-template-columns: 1fr;
    max-width: 650px;
    margin: 0 auto;
    gap: var(--spacing-md);
}

.tech-item.highlight-step {
    background: rgba(255, 255, 255, 0.03);
    padding: var(--spacing-md);
    border-radius: 10px;
    border-left: 4px solid var(--accent-blue);
    transition: all 0.2s ease;
    position: relative;
}

.tech-item.highlight-step::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 4px;
    background: linear-gradient(180deg, var(--accent-blue), rgba(69, 123, 157, 0.3));
    border-radius: 4px 0 0 4px;
}

.tech-item.highlight-step:hover {
    background: rgba(255, 255, 255, 0.05);
    transform: translateX(4px);
}

body.light-mode .tech-item.highlight-step {
    background: rgba(69, 123, 157, 0.03);
}

body.light-mode .tech-item.highlight-step:hover {
    background: rgba(69, 123, 157, 0.06);
}

.tech-item h4 {
    font-family: var(--font-mono);
    font-size: var(--fs-base);
    color: var(--text-primary);
    margin-bottom: var(--spacing-xs);
    text-transform: uppercase;
    letter-spacing: 0.03em;
    font-weight: 800;
}

.tech-item p {
    font-size: var(--fs-sm);
    color: var(--text-muted);
    line-height: 1.6;
    margin: 0;
}

.tech-item p strong {
    color: var(--text-primary);
    font-weight: 700;
}

/* Receipt Components - Shared across pages */
.receipt {
    transition: opacity 0.3s ease, transform 0.3s ease;
}

.receipt.hidden {
    display: none;
}

.receipt-edge {
    height: 14px;
    background: #faf6ef;
    position: relative;
}

.receipt-edge.top {
    border-radius: 6px 6px 0 0;
    mask-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 200 12'%3E%3Cpath d='M0,12 Q5,0 10,12 Q15,0 20,12 Q25,0 30,12 Q35,0 40,12 Q45,0 50,12 Q55,0 60,12 Q65,0 70,12 Q75,0 80,12 Q85,0 90,12 Q95,0 100,12 Q105,0 110,12 Q115,0 120,12 Q125,0 130,12 Q135,0 140,12 Q145,0 150,12 Q155,0 160,12 Q165,0 170,12 Q175,0 180,12 Q185,0 190,12 Q195,0 200,12 L200,12 L0,12 Z' fill='white'/%3E%3C/svg%3E");
    -webkit-mask-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 200 12'%3E%3Cpath d='M0,12 Q5,0 10,12 Q15,0 20,12 Q25,0 30,12 Q35,0 40,12 Q45,0 50,12 Q55,0 60,12 Q65,0 70,12 Q75,0 80,12 Q85,0 90,12 Q95,0 100,12 Q105,0 110,12 Q115,0 120,12 Q125,0 130,12 Q135,0 140,12 Q145,0 150,12 Q155,0 160,12 Q165,0 170,12 Q175,0 180,12 Q185,0 190,12 Q195,0 200,12 L200,12 L0,12 Z' fill='white'/%3E%3C/svg%3E");
    mask-size: 100% 100%;
    -webkit-mask-size: 100% 100%;
}

.receipt-edge.bottom {
    border-radius: 0 0 6px 6px;
    mask-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 200 12'%3E%3Cpath d='M0,0 L200,0 L200,0 Q195,12 190,0 Q185,12 180,0 Q175,12 170,0 Q165,12 160,0 Q155,12 150,0 Q145,12 140,0 Q135,12 130,0 Q125,12 120,0 Q115,12 110,0 Q105,12 100,0 Q95,12 90,0 Q85,12 80,0 Q75,12 70,0 Q65,12 60,0 Q55,12 50,0 Q45,12 40,0 Q35,12 30,0 Q25,12 20,0 Q15,12 10,0 Q5,12 0,0 Z' fill='white'/%3E%3C/svg%3E");
    -webkit-mask-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 200 12'%3E%3Cpath d='M0,0 L200,0 L200,0 Q195,12 190,0 Q185,12 180,0 Q175,12 170,0 Q165,12 160,0 Q155,12 150,0 Q145,12 140,0 Q135,12 130,0 Q125,12 120,0 Q115,12 110,0 Q105,12 100,0 Q95,12 90,0 Q85,12 80,0 Q75,12 70,0 Q65,12 60,0 Q55,12 50,0 Q45,12 40,0 Q35,12 30,0 Q25,12 20,0 Q15,12 10,0 Q5,12 0,0 Z' fill='white'/%3E%3C/svg%3E");
    mask-size: 100% 100%;
    -webkit-mask-size: 100% 100%;
}

.receipt-body {
    background: #ffffff;
    padding: var(--spacing-sm) 1.5rem;
    font-family: var(--font-mono);
    color: #1d3557;
    position: relative;
    isolation: isolate;
    box-shadow: var(--receipt-shadow);
    border: var(--receipt-border);
    font-size: var(--fs-base);
}

.receipt-body::before {
    content: '';
    position: absolute;
    inset: 0;
    z-index: 0;
    background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.03'/%3E%3C/svg%3E");
    pointer-events: none;
}

.receipt-body > * {
    position: relative;
    z-index: 1;
}

.receipt-header {
    text-align: center;
    margin-bottom: var(--spacing-xs);
}

.divider {
    height: 1.5px;
    background: rgba(0, 0, 0, 0.1);
    margin: var(--spacing-xs) 0;
}

.divider.dashed {
    border-top: 1.5px dashed rgba(0, 0, 0, 0.15);
    background: transparent;
    height: 0;
}

.divider.double {
    height: 4px;
    border-top: 1.5px solid #444;
    border-bottom: 1.5px solid #444;
    background: transparent;
    margin: var(--spacing-sm) 0;
}

.group-badge {
    font-size: 0.75rem;
    font-weight: 800;
    color: #fff;
    padding: 0.25rem 0.6rem;
    border-radius: 4px;
    letter-spacing: 0.05em;
    display: inline-block;
    vertical-align: middle;
}

/* Responsiveness - Standardized breakpoints */
@media (max-width: 1200px) {
    .page-header h1 {
        font-size: 2.8rem !important;
        font-weight: 850;
    }
}

@media (max-width: 850px) {
    body {
        padding: var(--spacing-md) var(--spacing-sm);
    }

    .page-header h1 {
        font-size: 2.4rem !important;
        font-weight: 850;
    }

    .nav-toggle {
        margin-bottom: var(--spacing-md);
    }

    .filter-bar {
        margin-bottom: var(--spacing-lg);
    }

    .receipt-body {
        padding: var(--spacing-sm) 1.25rem;
    }
}

@media (max-width: 600px) {
    body {
        padding: var(--spacing-md) var(--spacing-sm);
    }

    .page-header {
        margin-top: var(--spacing-lg);
    }

    .page-header h1 {
        font-size: 2.6rem !important;
        margin-bottom: 0.2rem !important;
        letter-spacing: -0.01em;
    }

    .page-header p {
        font-size: 0.95rem !important;
        line-height: 1.4 !important;
    }

    .brand-logo {
        font-size: 1.8rem !important;
        top: 1.8rem;
        left: 1.2rem;
    }

    .theme-toggle {
        top: var(--spacing-sm);
        right: var(--spacing-sm);
        width: 34px;
        height: 34px;
        font-size: 0.85rem;
    }

    .nav-toggle {
        gap: var(--spacing-xs);
        margin-bottom: var(--spacing-md);
        margin-top: 4.5rem;
        border-top: 1px solid var(--filter-border);
        padding-top: var(--spacing-sm);
    }

    .nav-link {
        font-size: 0.75rem;
        padding: 0.4rem 0.8rem;
    }

    .intro-dropdown {
        margin-bottom: var(--spacing-lg);
        border-radius: 8px;
    }

    .intro-dropdown summary {
        padding: var(--spacing-sm) var(--spacing-md);
        font-size: var(--fs-sm);
    }

    .intro-dropdown summary::before {
        font-size: var(--fs-sm);
        margin-right: var(--spacing-xs);
    }

    .intro-dropdown .dropdown-content {
        padding: var(--spacing-md);
    }

    .tech-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-sm);
    }

    .tech-item.highlight-step {
        padding: var(--spacing-sm);
    }

    .tech-item h4 {
        font-size: var(--fs-sm);
    }

    .tech-item p {
        font-size: var(--fs-xs);
    }
}

@media (max-width: 420px) {
    .receipt-body {
        padding: var(--spacing-sm);
    }
}

/* Projects Page Specific Components (Shared if needed) */
.intro-stats {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1.5rem;
    margin: 1rem 0 2.5rem;
}

.stat-badge {
    font-size: 0.95rem;
    font-weight: 600;
    background: var(--filter-bg);
    padding: 0.5rem 1.2rem;
    border-radius: 20px;
    border: 1px solid var(--filter-border);
}

.stat-group-breakdown {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.75rem;
}

.stat-group-breakdown .label {
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    opacity: 0.6;
    font-weight: 700;
}

.stat-group-breakdown .badges {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 0.6rem;
}

.intro-lead {
    margin-bottom: 1.5rem;
    color: var(--text-primary);
    font-size: 1rem;
    line-height: 1.6;
    font-style: italic;
    opacity: 0.9;
}

.success-criteria {
    margin-top: 2.5rem;
    padding-top: 2rem;
    border-top: 1px solid var(--filter-border);
}

.success-criteria h4 {
    font-family: var(--font-mono);
    font-size: 0.95rem;
    color: var(--text-primary);
    margin-bottom: 1.5rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.criteria-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
}

.criteria-item {
    background: rgba(var(--text-primary-rgb, 255, 255, 255), 0.03);
    padding: 1.25rem;
    border-radius: 12px;
    border: 1px solid var(--filter-border);
}
body.light-mode .criteria-item {
    background: rgba(0, 0, 0, 0.02);
}

.criteria-item .title {
    font-size: 1rem;
    font-weight: 800;
    color: var(--text-primary);
    margin-bottom: 0.75rem;
    font-family: var(--font-mono);
    letter-spacing: 0.02em;
}

.criteria-item p {
    font-size: 0.95rem;
    margin: 0;
    line-height: 1.5;
    color: var(--text-muted);
}