/* ========================================
   Unterweisungsplattform - Main Stylesheet
   Security-focused, minimal, accessible
   ======================================== */

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

:root {
    /* Colors */
    --color-primary: #3b82f6;
    --color-primary-dark: #2563eb;
    --color-secondary: #6b7280;
    --color-success: #22c55e;
    --color-success-dark: #16a34a;
    --color-warning: #f59e0b;
    --color-error: #ef4444;
    --color-error-dark: #dc2626;

    --color-text: #1f2937;
    --color-text-light: #6b7280;
    --color-background: #f9fafb;
    --color-surface: #ffffff;
    --color-border: #e5e7eb;

    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;

    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 2rem;

    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-full: 9999px;

    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-background);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.3;
    color: var(--color-text);
}

h1 { font-size: var(--font-size-3xl); }
h2 { font-size: var(--font-size-2xl); }
h3 { font-size: var(--font-size-xl); }

p {
    margin-bottom: var(--spacing-md);
}

a {
    color: var(--color-primary);
    text-decoration: none;
    transition: color 0.2s;
}

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

/* Layout */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

.main {
    flex: 1;
    padding: var(--spacing-2xl) 0;
}

/* Header */
.header {
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    padding: var(--spacing-md) 0;
}

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

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--color-text);
}

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

.logo-icon {
    font-size: 1.5rem;
}

.nav {
    display: flex;
    gap: var(--spacing-lg);
}

.nav a {
    color: var(--color-text-light);
    font-size: var(--font-size-sm);
}

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

/* Footer */
.footer {
    background: var(--color-surface);
    border-top: 1px solid var(--color-border);
    padding: var(--spacing-lg) 0;
    text-align: center;
    color: var(--color-text-light);
    font-size: var(--font-size-sm);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-sm) var(--spacing-lg);
    font-size: var(--font-size-base);
    font-weight: 500;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all 0.2s;
    text-decoration: none;
}

.btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

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

.btn-primary:hover:not(:disabled) {
    background: var(--color-primary-dark);
}

.btn-success {
    background: var(--color-success);
    color: white;
}

.btn-success:hover:not(:disabled) {
    background: var(--color-success-dark);
}

.btn-block {
    width: 100%;
}

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

/* Forms */
.form-group {
    margin-bottom: var(--spacing-lg);
}

.form-label {
    display: block;
    margin-bottom: var(--spacing-sm);
    font-weight: 500;
    color: var(--color-text);
}

.form-input {
    width: 100%;
    padding: var(--spacing-md);
    font-size: var(--font-size-base);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    transition: border-color 0.2s, box-shadow 0.2s;
    background: var(--color-surface);
}

.form-input:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.form-input:disabled {
    background: var(--color-background);
    cursor: not-allowed;
}

.form-hint {
    display: block;
    margin-top: var(--spacing-xs);
    font-size: var(--font-size-sm);
    color: var(--color-text-light);
}

/* Voucher Input */
.voucher-input {
    font-family: monospace;
    font-size: var(--font-size-xl);
    letter-spacing: 0.1em;
    text-align: center;
    text-transform: uppercase;
}

/* Cards */
.form-card,
.voucher-entry-card {
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-md);
    max-width: 450px;
    margin: 0 auto;
}

/* Flash Messages */
.flash-messages {
    margin-bottom: var(--spacing-lg);
}

.flash {
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-sm);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.flash-info {
    background: #eff6ff;
    color: #1e40af;
    border: 1px solid #bfdbfe;
}

.flash-success {
    background: #f0fdf4;
    color: #166534;
    border: 1px solid #bbf7d0;
}

.flash-warning {
    background: #fffbeb;
    color: #92400e;
    border: 1px solid #fde68a;
}

.flash-error {
    background: #fef2f2;
    color: #991b1b;
    border: 1px solid #fecaca;
}

.flash-close {
    background: none;
    border: none;
    font-size: 1.25rem;
    cursor: pointer;
    opacity: 0.7;
    color: inherit;
}

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

/* Error Messages */
.error-message {
    padding: var(--spacing-md);
    background: #fef2f2;
    color: #991b1b;
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-md);
    font-size: var(--font-size-sm);
}

/* Alert Boxes */
.alert {
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-lg);
}

.alert-warning {
    background: #fffbeb;
    color: #92400e;
    border: 1px solid #fde68a;
}

/* Hero Section */
.hero {
    text-align: center;
    padding: var(--spacing-2xl) 0;
}

.hero h1 {
    margin-bottom: var(--spacing-md);
}

.hero-subtitle {
    font-size: var(--font-size-lg);
    color: var(--color-text-light);
    margin-bottom: var(--spacing-2xl);
}

/* Features Grid */
.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-xl);
    margin-top: var(--spacing-2xl);
    padding-top: var(--spacing-2xl);
    border-top: 1px solid var(--color-border);
}

.feature {
    text-align: center;
    padding: var(--spacing-lg);
}

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

.feature h3 {
    margin-bottom: var(--spacing-sm);
}

.feature p {
    color: var(--color-text-light);
    font-size: var(--font-size-sm);
    margin: 0;
}

/* CAPTCHA Container */
.captcha-container,
.captcha-group {
    display: flex;
    justify-content: center;
    margin: var(--spacing-lg) 0;
}

/* Loading Spinner */
.spinner {
    display: inline-block;
    width: 16px;
    height: 16px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-top-color: white;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

.btn-loading {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
}

/* Error Pages */
.error-page {
    text-align: center;
    padding: var(--spacing-2xl) 0;
}

.error-page .error-icon {
    font-size: 4rem;
    margin-bottom: var(--spacing-lg);
}

.error-page h1 {
    margin-bottom: var(--spacing-md);
}

.error-page p {
    color: var(--color-text-light);
    margin-bottom: var(--spacing-xl);
}

/* Help Text */
.help-text {
    text-align: center;
    color: var(--color-text-light);
    font-size: var(--font-size-sm);
    margin-top: var(--spacing-xl);
}

/* Completion Section */
.completion-section {
    margin-top: var(--spacing-xl);
}

.completion-card {
    background: linear-gradient(135deg, #ecfdf5, #d1fae5);
    border-radius: var(--radius-lg);
    padding: var(--spacing-2xl);
    text-align: center;
}

.completion-card h2 {
    color: #065f46;
    margin-bottom: var(--spacing-md);
}

.completion-card p {
    color: #047857;
    margin-bottom: var(--spacing-lg);
}

/* Responsive */
@media (max-width: 768px) {
    .header .container {
        flex-direction: column;
        gap: var(--spacing-md);
    }

    .nav {
        gap: var(--spacing-md);
    }

    .hero {
        padding: var(--spacing-xl) 0;
    }

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

    .form-card,
    .voucher-entry-card {
        padding: var(--spacing-lg);
    }

    .voucher-input {
        font-size: var(--font-size-lg);
    }
}

/* Print Styles */
@media print {
    .header,
    .footer,
    .flash-messages {
        display: none;
    }

    .main {
        padding: 0;
    }
}

/* Accessibility */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Focus Styles */
*:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}