/**
 * MATHE-AUFGABEN.DE - Stylesheet
 * 
 * Design-Konzept: Spielerisch-mathematisch
 * - Geometrische Formen als Dekoration
 * - Frische, einladende Farben
 * - Klare Typografie für Lesbarkeit
 * - Subtile Animationen für Engagement
 */

/* =====================================================
   CSS VARIABLES
   ===================================================== */
:root {
    /* Hauptfarben */
    --color-primary: #4F46E5;
    --color-primary-dark: #4338CA;
    --color-primary-light: #818CF8;
    --color-primary-bg: #EEF2FF;
    
    /* Akzentfarben */
    --color-accent: #F59E0B;
    --color-accent-dark: #D97706;
    --color-success: #10B981;
    --color-success-bg: #D1FAE5;
    --color-error: #EF4444;
    --color-error-bg: #FEE2E2;
    --color-warning: #F59E0B;
    --color-info: #3B82F6;
    
    /* Schwierigkeits-Farben */
    --color-easy: #10B981;
    --color-medium: #F59E0B;
    --color-hard: #EF4444;
    --color-expert: #8B5CF6;
    
    /* Neutrale Farben */
    --color-text: #1F2937;
    --color-text-light: #6B7280;
    --color-text-muted: #9CA3AF;
    --color-bg: #FAFBFC;
    --color-bg-alt: #F3F4F6;
    --color-white: #FFFFFF;
    --color-border: #E5E7EB;
    --color-border-light: #F3F4F6;
    
    /* Schatten */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --shadow-glow: 0 0 20px rgba(79, 70, 229, 0.3);
    
    /* Typografie */
    --font-display: 'Space Mono', monospace;
    --font-body: 'Nunito', -apple-system, BlinkMacSystemFont, sans-serif;
    
    /* Abstände */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-full: 9999px;
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 350ms ease;
    
    /* Container */
    --container-max: 1200px;
    --container-padding: 1.5rem;
}

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-body);
    font-size: 1rem;
    line-height: 1.6;
    color: var(--color-text);
    background: var(--color-bg);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    position: relative;
    overflow-x: hidden;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

a {
    color: var(--color-primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

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

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    background: none;
}

input, textarea, select {
    font-family: inherit;
    font-size: inherit;
}

ul, ol {
    list-style: none;
}

/* Screen Reader Only */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* =====================================================
   UTILITIES
   ===================================================== */
.container {
    width: 100%;
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--container-padding);
}

.text-center { text-align: center; }
.text-muted { color: var(--color-text-light); }

/* =====================================================
   BACKGROUND DECORATION (Geometrische Formen)
   ===================================================== */
.bg-decoration {
    position: fixed;
    inset: 0;
    pointer-events: none;
    z-index: -1;
    overflow: hidden;
}

.shape {
    position: absolute;
    opacity: 0.5;
}

.shape-1 {
    top: 10%;
    left: -5%;
    width: 300px;
    height: 300px;
    background: linear-gradient(135deg, var(--color-primary-bg) 0%, transparent 70%);
    border-radius: 30% 70% 70% 30% / 30% 30% 70% 70%;
    animation: float 20s ease-in-out infinite;
}

.shape-2 {
    top: 60%;
    right: -10%;
    width: 400px;
    height: 400px;
    background: linear-gradient(225deg, rgba(245, 158, 11, 0.1) 0%, transparent 70%);
    border-radius: 70% 30% 30% 70% / 60% 40% 60% 40%;
    animation: float 25s ease-in-out infinite reverse;
}

.shape-3 {
    bottom: 10%;
    left: 20%;
    width: 200px;
    height: 200px;
    background: linear-gradient(45deg, rgba(16, 185, 129, 0.1) 0%, transparent 70%);
    clip-path: polygon(50% 0%, 100% 50%, 50% 100%, 0% 50%);
    animation: spin 30s linear infinite;
}

.shape-4 {
    top: 30%;
    right: 20%;
    width: 150px;
    height: 150px;
    border: 3px solid var(--color-primary-bg);
    border-radius: var(--radius-lg);
    transform: rotate(45deg);
    animation: float 15s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0) rotate(0deg); }
    50% { transform: translateY(-30px) rotate(5deg); }
}

@keyframes spin {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

/* =====================================================
   HEADER
   ===================================================== */
.site-header {
    background: var(--color-white);
    border-bottom: 1px solid var(--color-border-light);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow-sm);
}

.header-inner {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
    padding: var(--spacing-md) 0;
}

/* Logo */
.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    color: var(--color-text);
    font-weight: 700;
    flex-shrink: 0;
}

.logo:hover {
    color: var(--color-text);
}

.logo-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 44px;
    height: 44px;
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
    color: white;
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 700;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    transition: transform var(--transition-fast), box-shadow var(--transition-fast);
}

.logo:hover .logo-icon {
    transform: scale(1.05) rotate(-5deg);
    box-shadow: var(--shadow-glow);
}

.logo-text {
    display: flex;
    flex-direction: column;
    line-height: 1.1;
}

.logo-main {
    font-family: var(--font-display);
    font-size: 1.1rem;
}

.logo-sub {
    font-size: 0.75rem;
    color: var(--color-primary);
}

/* Search */
.search-wrapper {
    flex: 1;
    max-width: 500px;
    position: relative;
}

.search-form {
    display: flex;
    align-items: stretch;
    background: var(--color-bg-alt);
    border: 2px solid transparent;
    border-radius: var(--radius-full);
    transition: all var(--transition-fast);
}

.search-form:focus-within {
    background: var(--color-white);
    border-color: var(--color-primary);
    box-shadow: 0 0 0 4px var(--color-primary-bg);
}

.search-input {
    flex: 1;
    padding: var(--spacing-sm) var(--spacing-lg);
    background: transparent;
    border: none;
    outline: none;
    font-size: 0.95rem;
}

.search-input::placeholder {
    color: var(--color-text-muted);
}

.search-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 44px;
    color: var(--color-text-light);
    transition: color var(--transition-fast);
}

.search-btn:hover {
    color: var(--color-primary);
}

/* Navigation */
.main-nav {
    display: flex;
    align-items: center;
}

.nav-toggle {
    display: none;
    width: 40px;
    height: 40px;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 5px;
}

.nav-toggle-icon,
.nav-toggle-icon::before,
.nav-toggle-icon::after {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--color-text);
    border-radius: 2px;
    transition: all var(--transition-fast);
}

.nav-toggle-icon {
    position: relative;
}

.nav-toggle-icon::before,
.nav-toggle-icon::after {
    content: '';
    position: absolute;
    left: 0;
}

.nav-toggle-icon::before { top: -7px; }
.nav-toggle-icon::after { bottom: -7px; }

.nav-menu {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.nav-link {
    display: block;
    padding: var(--spacing-sm) var(--spacing-md);
    color: var(--color-text);
    font-weight: 600;
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
}

.nav-link:hover {
    color: var(--color-primary);
    background: var(--color-primary-bg);
}

.nav-highlight {
    background: linear-gradient(135deg, var(--color-accent), var(--color-accent-dark));
    color: white !important;
}

.nav-highlight:hover {
    background: linear-gradient(135deg, var(--color-accent-dark), var(--color-accent));
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

/* User Area */
.user-area {
    flex-shrink: 0;
}

.user-info {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.user-points {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-xs) var(--spacing-sm);
    background: var(--color-accent);
    color: white;
    font-weight: 700;
    font-size: 0.9rem;
    border-radius: var(--radius-full);
}

.user-avatar {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: var(--color-primary);
    color: white;
    font-weight: 700;
    border-radius: 50%;
    transition: transform var(--transition-fast);
}

.user-avatar:hover {
    transform: scale(1.1);
}

/* =====================================================
   BUTTONS
   ===================================================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-lg);
    font-weight: 700;
    font-size: 0.95rem;
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
    cursor: pointer;
}

.btn-primary {
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
    color: white;
    box-shadow: var(--shadow-md);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
    color: white;
}

.btn-secondary {
    background: var(--color-bg-alt);
    color: var(--color-text);
}

.btn-secondary:hover {
    background: var(--color-border);
}

.btn-outline {
    border: 2px solid var(--color-primary);
    color: var(--color-primary);
    background: transparent;
}

.btn-outline:hover {
    background: var(--color-primary);
    color: white;
}

.btn-success {
    background: linear-gradient(135deg, var(--color-success), #059669);
    color: white;
}

.btn-lg {
    padding: var(--spacing-md) var(--spacing-xl);
    font-size: 1.1rem;
    border-radius: var(--radius-lg);
}

.btn-sm {
    padding: var(--spacing-xs) var(--spacing-md);
    font-size: 0.875rem;
}

.btn-icon {
    width: 44px;
    height: 44px;
    padding: 0;
    border-radius: var(--radius-md);
}

/* =====================================================
   MAIN CONTENT
   ===================================================== */
.site-main {
    flex: 1;
    padding: var(--spacing-2xl) 0;
}

/* =====================================================
   HERO SECTION (Startseite)
   ===================================================== */
.hero {
    text-align: center;
    padding: var(--spacing-3xl) 0;
    margin-bottom: var(--spacing-2xl);
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-xs) var(--spacing-md);
    background: var(--color-primary-bg);
    color: var(--color-primary);
    font-weight: 600;
    font-size: 0.875rem;
    border-radius: var(--radius-full);
    margin-bottom: var(--spacing-lg);
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% { box-shadow: 0 0 0 0 rgba(79, 70, 229, 0.4); }
    50% { box-shadow: 0 0 0 10px rgba(79, 70, 229, 0); }
}

.hero-title {
    font-family: var(--font-display);
    font-size: clamp(2rem, 5vw, 3.5rem);
    font-weight: 700;
    line-height: 1.1;
    margin-bottom: var(--spacing-lg);
    color: var(--color-text);
}

.hero-title span {
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--color-text-light);
    max-width: 600px;
    margin: 0 auto var(--spacing-xl);
}

.hero-actions {
    display: flex;
    justify-content: center;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

/* =====================================================
   DAILY CARDS (Aufgabe/Rätsel des Tages)
   ===================================================== */
.daily-section {
    margin-bottom: var(--spacing-3xl);
}

.daily-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(min(100%, 450px), 1fr));
    gap: var(--spacing-xl);
}

.daily-card {
    background: var(--color-white);
    border-radius: var(--radius-xl);
    overflow: hidden;
    box-shadow: var(--shadow-lg);
    transition: transform var(--transition-base), box-shadow var(--transition-base);
    position: relative;
}

.daily-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
}

.daily-card-header {
    padding: var(--spacing-lg);
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
    color: white;
    position: relative;
    overflow: hidden;
}

.daily-card-header.raetsel {
    background: linear-gradient(135deg, var(--color-accent), var(--color-accent-dark));
}

.daily-card-header::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 200px;
    height: 200px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
}

.daily-label {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: 0.875rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    opacity: 0.9;
    margin-bottom: var(--spacing-sm);
}

.daily-title {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-xs);
}

.daily-meta {
    display: flex;
    gap: var(--spacing-md);
    font-size: 0.875rem;
    opacity: 0.9;
}

.daily-card-body {
    padding: var(--spacing-xl);
}

.daily-task {
    font-size: 1.1rem;
    line-height: 1.7;
    margin-bottom: var(--spacing-lg);
    padding: var(--spacing-lg);
    background: var(--color-bg-alt);
    border-radius: var(--radius-lg);
    border-left: 4px solid var(--color-primary);
}

.daily-card-header.raetsel + .daily-card-body .daily-task {
    border-left-color: var(--color-accent);
}

.daily-answer-form {
    display: flex;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
}

.daily-input {
    flex: 1;
    padding: var(--spacing-md);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    font-size: 1rem;
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.daily-input:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 4px var(--color-primary-bg);
}

.daily-card-footer {
    padding: var(--spacing-md) var(--spacing-xl);
    background: var(--color-bg-alt);
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.875rem;
}

.daily-timer {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    color: var(--color-text-light);
}

.daily-points {
    font-weight: 700;
    color: var(--color-primary);
}

/* Difficulty Badge */
.difficulty-badge {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: 2px 10px;
    font-size: 0.75rem;
    font-weight: 700;
    border-radius: var(--radius-full);
    text-transform: uppercase;
}

.difficulty-badge.leicht { background: rgba(16, 185, 129, 0.2); color: var(--color-easy); }
.difficulty-badge.mittel { background: rgba(245, 158, 11, 0.2); color: var(--color-medium); }
.difficulty-badge.schwer { background: rgba(239, 68, 68, 0.2); color: var(--color-hard); }
.difficulty-badge.knifflig { background: rgba(139, 92, 246, 0.2); color: var(--color-expert); }

/* =====================================================
   THEMEN ÜBERSICHT
   ===================================================== */
.section-header {
    text-align: center;
    margin-bottom: var(--spacing-2xl);
}

.section-title {
    font-family: var(--font-display);
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
}

.section-subtitle {
    color: var(--color-text-light);
    font-size: 1.1rem;
}

.topics-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: var(--spacing-lg);
}

.topic-card {
    background: var(--color-white);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    text-align: center;
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
    border: 2px solid transparent;
}

.topic-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--color-primary-light);
}

.topic-icon {
    font-size: 2.5rem;
    margin-bottom: var(--spacing-md);
    display: block;
}

.topic-name {
    font-weight: 700;
    font-size: 1.1rem;
    color: var(--color-text);
    margin-bottom: var(--spacing-xs);
}

.topic-count {
    font-size: 0.875rem;
    color: var(--color-text-muted);
}

/* =====================================================
   AUFGABEN LISTE
   ===================================================== */
.tasks-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.task-item {
    background: var(--color-white);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
    transition: all var(--transition-fast);
    border: 1px solid var(--color-border-light);
}

.task-item:hover {
    box-shadow: var(--shadow-md);
    border-color: var(--color-primary-light);
}

.task-icon {
    width: 50px;
    height: 50px;
    background: var(--color-primary-bg);
    color: var(--color-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    border-radius: var(--radius-md);
    flex-shrink: 0;
}

.task-content {
    flex: 1;
    min-width: 0;
}

.task-title {
    font-weight: 700;
    font-size: 1.1rem;
    color: var(--color-text);
    margin-bottom: var(--spacing-xs);
}

.task-meta {
    display: flex;
    gap: var(--spacing-md);
    font-size: 0.875rem;
    color: var(--color-text-light);
}

.task-action {
    flex-shrink: 0;
}

/* =====================================================
   FEEDBACK MESSAGES
   ===================================================== */
.feedback {
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    margin-top: var(--spacing-md);
    animation: slideIn 0.3s ease;
}

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

.feedback-success {
    background: var(--color-success-bg);
    border: 2px solid var(--color-success);
    color: #065F46;
}

.feedback-error {
    background: var(--color-error-bg);
    border: 2px solid var(--color-error);
    color: #991B1B;
}

.feedback-title {
    font-weight: 700;
    font-size: 1.1rem;
    margin-bottom: var(--spacing-sm);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.feedback-text {
    line-height: 1.6;
}

/* =====================================================
   FOOTER
   ===================================================== */
.site-footer {
    background: var(--color-text);
    color: rgba(255, 255, 255, 0.8);
    padding: var(--spacing-3xl) 0 var(--spacing-xl);
    margin-top: auto;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-2xl);
    margin-bottom: var(--spacing-2xl);
}

.footer-title {
    color: white;
    font-size: 1.1rem;
    font-weight: 700;
    margin-bottom: var(--spacing-lg);
}

.footer-text {
    font-size: 0.95rem;
    line-height: 1.7;
    margin-bottom: var(--spacing-lg);
}

.footer-links li {
    margin-bottom: var(--spacing-sm);
}

.footer-links a {
    color: rgba(255, 255, 255, 0.7);
    font-size: 0.95rem;
    transition: color var(--transition-fast);
}

.footer-links a:hover {
    color: white;
}

.footer-social {
    display: flex;
    gap: var(--spacing-md);
}

.social-link {
    font-size: 1.5rem;
    transition: transform var(--transition-fast);
}

.social-link:hover {
    transform: scale(1.2);
}

.footer-bottom {
    padding-top: var(--spacing-xl);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    text-align: center;
}

.copyright {
    font-size: 0.875rem;
    margin-bottom: var(--spacing-xs);
}

.footer-tagline {
    font-family: var(--font-display);
    font-size: 0.875rem;
    color: var(--color-primary-light);
}

/* =====================================================
   RESPONSIVE
   ===================================================== */
@media (max-width: 768px) {
    :root {
        --container-padding: 1rem;
    }
    
    .header-inner {
        flex-wrap: wrap;
    }
    
    .search-wrapper {
        order: 3;
        max-width: 100%;
        width: 100%;
        margin-top: var(--spacing-md);
    }
    
    .nav-toggle {
        display: flex;
    }
    
    .nav-menu {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: var(--color-white);
        flex-direction: column;
        padding: var(--spacing-md);
        box-shadow: var(--shadow-lg);
        border-top: 1px solid var(--color-border);
    }
    
    .nav-menu.active {
        display: flex;
    }
    
    .nav-link {
        padding: var(--spacing-md);
    }
    
    .hero-title {
        font-size: 1.75rem;
    }
    
    .hero-actions {
        flex-direction: column;
        align-items: stretch;
    }
    
    .daily-grid {
        grid-template-columns: 1fr;
    }
    
    .task-item {
        flex-direction: column;
        text-align: center;
    }
    
    .task-meta {
        justify-content: center;
    }
}

/* =====================================================
   PRINT STYLES
   ===================================================== */
@media print {
    .site-header,
    .site-footer,
    .bg-decoration,
    .daily-answer-form,
    .btn {
        display: none !important;
    }
    
    body {
        background: white;
        color: black;
    }
    
    .daily-card {
        box-shadow: none;
        border: 1px solid #ccc;
    }
}