/* ====================================
   FRANZÖSISCHE GESCHÄFTSKORRESPONDENZ
   E-Book Stylesheet
   ==================================== */

/* Google Fonts Import */
@import url('https://fonts.googleapis.com/css2?family=Orbitron:wght@400;500;600;700;800;900&family=Inter:wght@300;400;500;600;700&display=swap');

/* CSS Variables - Dark Mode (Default) */
:root {
    --bs-dark: #0F172A;
    --bs-accent: #3B82F6;
    --bs-highlight: #06B6D4;
    --bs-success: #10B981;
    --bs-warning: #F59E0B;
    --bs-light: #F1F5F9;
    --bs-danger: #EF4444;
    --bs-text: #F8FAFC;
    --bg-primary: #0F172A;
    --bg-secondary: #1E293B;
    --bg-glass: rgba(15, 23, 42, 0.7);
    --border-color: rgba(255, 255, 255, 0.1);
    --text-primary: #F8FAFC;
    --text-secondary: rgba(248, 250, 252, 0.8);
    
    /* Typography Variables */
    --font-heading: 'Orbitron', sans-serif;
    --font-body: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: 'JetBrains Mono', 'Courier New', monospace;
}

/* Light Mode Variables */
[data-theme="light"] {
    --bs-dark: #FFFFFF;
    --bs-accent: #3B82F6;
    --bs-highlight: #06B6D4;
    --bs-success: #10B981;
    --bs-warning: #F59E0B;
    --bs-light: #1F2937;
    --bs-danger: #EF4444;
    --bs-text: #1F2937;
    --bg-primary: #F9FAFB;
    --bg-secondary: #FFFFFF;
    --bg-glass: rgba(255, 255, 255, 0.95);
    --border-color: rgba(0, 0, 0, 0.1);
    --text-primary: #1F2937;
    --text-secondary: #4B5563;
}

/* Light Mode: Override Bootstrap's .text-light class to be dark text */
[data-theme="light"] .text-light {
    color: #1F2937 !important;
}

/* Light Mode: Ensure all headings are dark/black */
[data-theme="light"] h1,
[data-theme="light"] h2,
[data-theme="light"] h3,
[data-theme="light"] h4,
[data-theme="light"] h5,
[data-theme="light"] h6 {
    color: #1F2937 !important;
}

/* Base Styles */
body {
    font-family: var(--font-body);
    font-size: clamp(1rem, 1vw + 0.75rem, 1.125rem);
    line-height: 1.7;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    position: relative;
    overflow-x: hidden;
    font-weight: 400;
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* Dark Mode Grid Background */
body:not([data-theme="light"]) {
    background-image: linear-gradient(rgba(255, 255, 255, 0.03) 1px, transparent 1px),
                      linear-gradient(90deg, rgba(255, 255, 255, 0.03) 1px, transparent 1px);
    background-size: 20px 20px;
}

/* Light Mode Subtle Background */
body[data-theme="light"] {
    background-image: linear-gradient(rgba(0, 0, 0, 0.02) 1px, transparent 1px),
                      linear-gradient(90deg, rgba(0, 0, 0, 0.02) 1px, transparent 1px);
    background-size: 20px 20px;
}

/* Typography Hierarchy - Orbitron for Headings */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    color: var(--bs-light);
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 1rem;
    letter-spacing: 0.02em;
}

h1 {
    font-size: clamp(2rem, 4vw + 1rem, 3.5rem);
    font-weight: 900;
    letter-spacing: -0.02em;
    margin-bottom: 1.5rem;
}

h2 {
    font-size: clamp(1.75rem, 3vw + 0.75rem, 2.75rem);
    font-weight: 800;
    margin-bottom: 1.25rem;
}

h3 {
    font-size: clamp(1.5rem, 2.5vw + 0.5rem, 2.25rem);
    font-weight: 700;
}

h4 {
    font-size: clamp(1.25rem, 2vw + 0.5rem, 1.75rem);
    font-weight: 600;
}

h5 {
    font-size: clamp(1.125rem, 1.5vw + 0.5rem, 1.5rem);
    font-weight: 600;
}

h6 {
    font-size: clamp(1rem, 1vw + 0.5rem, 1.25rem);
    font-weight: 600;
}

/* Body Text */
p {
    margin-bottom: 1rem;
    color: var(--bs-text);
    line-height: 1.7;
}

li {
    color: var(--bs-text);
    line-height: 1.6;
    margin-bottom: 0.5rem;
}

/* Strong emphasis */
strong, b {
    font-weight: 600;
}

/* Subtle emphasis */
em, i {
    font-style: italic;
}

/* Links */
a {
    color: var(--bs-accent);
    text-decoration: none;
    transition: color 0.3s;
}

a:hover {
    color: var(--bs-highlight);
}

/* Glass Effect */
.bg-glass {
    background-color: var(--bg-glass);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    transition: background-color 0.3s ease, border-color 0.3s ease;
}

/* Light Mode Glass Shadow */
[data-theme="light"] .bg-glass {
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

/* Gradient Text */
.text-gradient {
    background: linear-gradient(to right, var(--bs-accent), var(--bs-highlight));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    font-family: var(--font-heading);
}

/* Main Title Override */
.display-3,
.display-4 {
    font-family: var(--font-heading) !important;
    font-weight: 900 !important;
    letter-spacing: -0.02em;
}

/* Chapter Cards */
.chapter-card {
    transition: all 0.3s ease;
    height: 100%;
}

.chapter-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px -5px rgba(59, 130, 246, 0.1);
    border: 1px solid rgba(59, 130, 246, 0.2);
}

/* Accordion Styles */
.accordion-button {
    background-color: var(--bg-glass) !important;
    color: var(--text-primary) !important;
    border: none !important;
    box-shadow: none !important;
    transition: background-color 0.3s ease, color 0.3s ease !important;
}

.accordion-button:not(.collapsed) {
    color: var(--bs-accent) !important;
    background-color: rgba(59, 130, 246, 0.1) !important;
}

[data-theme="light"] .accordion-button {
    background-color: var(--bg-glass) !important;
}

.accordion-button::after {
    background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16' fill='%23F1F5F9'%3e%3cpath fill-rule='evenodd' d='M1.646 4.646a.5.5 0 0 1 .708 0L8 10.293l5.646-5.647a.5.5 0 0 1 .708.708l-6 6a.5.5 0 0 1-.708 0l-6-6a.5.5 0 0 1 0-.708z'/%3e%3c/svg%3e");
}

.accordion-button:not(.collapsed)::after {
    background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16' fill='%233B82F6'%3e%3cpath fill-rule='evenodd' d='M7.646 4.646a.5.5 0 0 1 .708 0l6 6a.5.5 0 0 1-.708.708L8 5.707l-5.646 5.647a.5.5 0 0 1-.708-.708l6-6z'/%3e%3c/svg%3e");
}

.accordion-item {
    background-color: transparent;
    border: 1px solid var(--border-color);
    margin-bottom: 0.5rem;
    transition: border-color 0.3s ease;
}

.accordion-body {
    background-color: var(--bg-glass);
    transition: background-color 0.3s ease;
}

[data-theme="light"] .accordion-body {
    color: var(--text-primary);
}

/* Fix: Accordion body headings should be white */
.accordion-body h1,
.accordion-body h2,
.accordion-body h3,
.accordion-body h4,
.accordion-body h5,
.accordion-body h6 {
    color: var(--bs-light) !important;
}

/* Letter Examples */
.letter-example {
    white-space: pre-line;
    font-family: var(--font-mono);
    font-size: clamp(0.875rem, 0.5vw + 0.75rem, 1rem);
    line-height: 1.8;
    color: var(--text-primary);
    padding: clamp(1rem, 2vw, 1.5rem);
    background-color: var(--bg-glass);
    border-radius: 0.5rem;
    border-left: 3px solid var(--bs-accent);
    transition: background-color 0.3s ease, color 0.3s ease;
}

[data-theme="light"] .letter-example {
    background-color: rgba(249, 250, 251, 0.9);
    border-left: 3px solid var(--bs-accent);
}

/* Vocabulary Tables */
.vocab-table {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0;
    border-radius: 0.5rem;
    overflow: hidden;
}

.vocab-table th {
    background-color: var(--bs-accent);
    color: var(--bs-dark);
    font-family: var(--font-heading);
    font-weight: 700;
    font-size: clamp(0.875rem, 0.5vw + 0.75rem, 1rem);
    text-align: left;
    padding: clamp(0.75rem, 1vw, 1rem) clamp(1rem, 1.5vw, 1.25rem);
    letter-spacing: 0.05em;
    text-transform: uppercase;
}

.vocab-table td {
    padding: clamp(0.75rem, 1vw, 1rem) clamp(1rem, 1.5vw, 1.25rem);
    border-top: 1px solid rgba(200, 200, 200, 0.3);
    color: #1F2937 !important;
    font-family: var(--font-body);
    font-size: clamp(0.875rem, 0.5vw + 0.75rem, 1rem);
    line-height: 1.6;
    vertical-align: top;
}

.vocab-table tr {
    background-color: #FFFFFF !important;
}

.vocab-table tr:nth-child(even) {
    background-color: #F9FAFB !important;
}

/* Phrase Collections */
.phrase-group {
    margin-bottom: clamp(1.5rem, 3vw, 2rem);
}

.phrase-title {
    font-family: var(--font-heading);
    color: var(--bs-accent);
    margin-bottom: 1rem;
    font-weight: 700;
    font-size: clamp(1.125rem, 1.5vw + 0.5rem, 1.5rem);
}

.phrase-french,
.phrase-german {
    font-family: var(--font-body);
    font-size: clamp(0.9375rem, 0.5vw + 0.75rem, 1.0625rem);
    line-height: 1.7;
}

.phrase-item {
    margin-bottom: 1rem;
    padding: 0.75rem;
    border-radius: 0.5rem;
    background-color: var(--bg-glass);
    transition: background-color 0.3s ease;
}

.phrase-item:hover {
    background-color: rgba(59, 130, 246, 0.1);
}

.phrase-french {
    color: var(--text-primary);
    font-weight: 600;
    margin-bottom: 0.25rem;
}

.phrase-german {
    color: var(--text-secondary);
    font-style: italic;
}

[data-theme="light"] .phrase-item {
    background-color: rgba(249, 250, 251, 0.7);
}

[data-theme="light"] .phrase-item:hover {
    background-color: rgba(59, 130, 246, 0.05);
}

/* Exercise Sections */
.exercise {
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    border-radius: 0.75rem;
    background-color: var(--bg-glass);
    border: 1px solid var(--border-color);
    transition: background-color 0.3s ease, border-color 0.3s ease;
}

.exercise-title {
    font-family: var(--font-heading);
    color: var(--bs-highlight);
    margin-bottom: 1rem;
    font-weight: 700;
    font-size: clamp(1.125rem, 1.5vw + 0.5rem, 1.5rem);
}

/* Progress Indicators */
.progress-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 5px;
    background: transparent;
    z-index: 9999;
}

.progress-bar {
    height: 100%;
    background: linear-gradient(to right, var(--bs-accent), var(--bs-highlight));
    width: 0%;
}

/* Burger Navigation - Always Visible */
.burger-nav {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    background-color: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    padding: 0.75rem 1rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    transition: background-color 0.3s ease, border-color 0.3s ease;
}

.burger-nav h1 {
    font-family: var(--font-heading);
    font-size: clamp(1.25rem, 2vw + 0.5rem, 1.75rem);
    font-weight: 900;
    margin: 0;
    letter-spacing: 0.02em;
    color: var(--text-primary);
}

/* Theme Toggle Button */
.theme-toggle {
    background: none;
    border: 2px solid var(--bs-accent);
    color: var(--bs-accent);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    margin-left: 1rem;
    transition: all 0.3s ease;
    font-size: 1.25rem;
}

.theme-toggle:hover {
    background-color: var(--bs-accent);
    color: white;
    transform: rotate(180deg);
}

/* Mobile Menu */
.mobile-menu {
    position: fixed;
    top: 0;
    left: -320px;
    width: 320px;
    height: 100vh;
    background-color: var(--bg-secondary);
    border-right: 1px solid var(--border-color);
    z-index: 1001;
    transition: left 0.3s ease, background-color 0.3s ease, border-color 0.3s ease;
    overflow-y: auto;
    padding: 1rem 0;
}

.mobile-menu.open {
    left: 0;
}

.mobile-menu-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    background-color: rgba(0, 0, 0, 0.5);
    z-index: 1000;
    display: none;
}

.mobile-menu-overlay.open {
    display: block;
}

/* Buttons */
.btn,
.btn-accent,
.btn-outline-accent {
    font-family: var(--font-body);
    font-weight: 500;
    font-size: clamp(0.875rem, 0.5vw + 0.75rem, 1rem);
    letter-spacing: 0.025em;
}

.btn-accent {
    background-color: var(--bs-accent);
    color: var(--bs-light);
    border: none;
}

.btn-accent:hover {
    background-color: #2563eb;
    color: var(--bs-light);
}

.btn-outline-accent {
    background-color: transparent;
    color: var(--bs-accent);
    border: 1px solid var(--bs-accent);
}

.btn-outline-accent:hover {
    background-color: var(--bs-accent);
    color: var(--bs-light);
}

/* Cultural Tips */
.cultural-tip {
    padding: 1rem;
    margin-bottom: 1rem;
    border-radius: 0.5rem;
    background-color: rgba(6, 182, 212, 0.1);
    border-left: 3px solid var(--bs-highlight);
}

.cultural-tip-title {
    color: var(--bs-highlight);
    font-weight: 600;
    margin-bottom: 0.5rem;
}

/* Floating Action Button */
.fab {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 3.5rem;
    height: 3.5rem;
    background-color: var(--bs-accent);
    color: var(--bs-light);
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    z-index: 999;
    cursor: pointer;
    transition: all 0.3s;
}

.fab:hover {
    background-color: #2563eb;
    transform: scale(1.05);
}

/* Quick Navigation Menu */
.quick-nav {
    position: fixed;
    bottom: 6rem;
    right: 2rem;
    background-color: var(--bs-dark);
    border-radius: 0.5rem;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.1);
    z-index: 998;
    opacity: 0;
    transform: translateY(20px);
    transition: all 0.3s;
    pointer-events: none;
    max-height: 70vh;
    overflow-y: auto;
}

.quick-nav.open {
    opacity: 1;
    transform: translateY(0);
    pointer-events: all;
}

.quick-nav-item {
    padding: 0.5rem 1rem;
    color: var(--bs-text);
    display: block;
    transition: all 0.3s;
    white-space: nowrap;
}

.quick-nav-item:hover {
    background-color: rgba(59, 130, 246, 0.1);
    color: var(--bs-accent);
}

/* Content Container */
.content-container {
    margin-top: 60px;
    padding: 2rem 1rem;
}

/* Print Styles */
@media print {
    body {
        background: white;
        color: black;
    }

    .bg-glass {
        background-color: white;
        backdrop-filter: none;
        border: 1px solid #ddd;
    }

    .burger-nav, .fab, .quick-nav, .progress-container, .mobile-menu, .mobile-menu-overlay {
        display: none !important;
    }

    h1, h2, h3, h4, h5, h6 {
        color: black;
    }

    p, li, td, th {
        color: black;
    }

    .letter-example, .phrase-item, .exercise, .cultural-tip {
        background-color: white;
        border: 1px solid #ddd;
    }

    .vocab-table th {
        background-color: #f0f0f0;
        color: black;
    }

    .vocab-table tr, .vocab-table tr:nth-child(even) {
        background-color: white;
    }

    .vocab-table td {
        color: black;
        border-top: 1px solid #ddd;
    }

    .phrase-french, .phrase-german {
        color: black;
    }

    .text-gradient {
        background: none;
        color: black;
    }

    a {
        color: black;
        text-decoration: underline;
    }

    .content-container {
        margin-top: 0;
    }
}

/* Responsive Adjustments */
@media (max-width: 768px) {
    .content-container {
        padding: 1rem 0.5rem;
    }

    .fab {
        bottom: 1rem;
        right: 1rem;
        width: 3rem;
        height: 3rem;
    }

    .quick-nav {
        bottom: 5rem;
        right: 1rem;
        max-width: calc(100vw - 2rem);
    }
}