/* ===============================================
   CSS Variables & Reset
   =============================================== */

:root {
    /* Colors - Inspired by mountains and nature */
    --color-primary: #2d5a4a;
    --color-primary-light: #3d7a5f;
    --color-primary-dark: #1d3a2a;
    --color-secondary: #8b7355;
    --color-accent: #d4a574;
    --color-accent-light: #e8c9a1;

    /* Neutrals */
    --color-bg: #faf9f7;
    --color-bg-secondary: #ffffff;
    --color-surface: #f5f3f0;
    --color-text: #2d2d2d;
    --color-text-secondary: #5a5a5a;
    --color-text-muted: #8a8a8a;
    --color-border: #e0ddd9;
    --color-shadow: rgba(45, 90, 74, 0.1);
    --color-shadow-strong: rgba(45, 90, 74, 0.15);

    /* Typography */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-display: 'Playfair Display', Georgia, serif;

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;

    /* Border Radius */
    --radius-sm: 0.5rem;
    --radius-md: 0.75rem;
    --radius-lg: 1rem;
    --radius-xl: 1.5rem;
    --radius-full: 9999px;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 350ms ease;

    /* Shadows */
    --shadow-sm: 0 1px 3px var(--color-shadow);
    --shadow-md: 0 4px 6px var(--color-shadow);
    --shadow-lg: 0 10px 15px var(--color-shadow-strong);
    --shadow-xl: 0 20px 25px var(--color-shadow-strong);
}

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

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

body {
    font-family: var(--font-primary);
    background-color: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
}

/* ===============================================
   Container & Layout
   =============================================== */

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

@media (min-width: 640px) {
    .container {
        padding: 0 var(--spacing-md);
    }
}

@media (min-width: 1024px) {
    .container {
        padding: 0 var(--spacing-lg);
    }
}

/* ===============================================
   Header
   =============================================== */

.header {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    color: white;
    padding: var(--spacing-sm) 0;
    box-shadow: var(--shadow-md);
    position: sticky;
    top: 0;
    z-index: 100;
    transition: padding var(--transition-base), box-shadow var(--transition-base);
}

.header-content {
    text-align: center;
}

.header-title {
    font-family: var(--font-display);
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: var(--spacing-xs);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    transition: font-size var(--transition-base);
}

.header-logo {
    height: 3rem;
    width: auto;
    object-fit: contain;
    filter: drop-shadow(0 2px 4px rgba(0,0,0,0.2));
    transition: height var(--transition-base);
}

.header-subtitle {
    font-size: 0.85rem;
    opacity: 0.9;
    font-weight: 300;
    transition: font-size var(--transition-base), opacity var(--transition-base);
}

/* Header cuando se hace scroll */
.header.scrolled {
    padding: var(--spacing-xs) 0;
    box-shadow: var(--shadow-lg);
}

.header.scrolled .header-logo {
    height: 2rem;
}

.header.scrolled .header-title {
    font-size: 1.1rem;
    margin-bottom: 0;
}

.header.scrolled .header-subtitle {
    font-size: 0.75rem;
    opacity: 0.8;
}

@media (min-width: 640px) {
    .header {
        padding: var(--spacing-md) 0;
    }

    .header-title {
        font-size: 1.75rem;
        gap: var(--spacing-sm);
    }

    .header-logo {
        height: 4.5rem;
    }

    .header-subtitle {
        font-size: 1rem;
    }

    .header.scrolled {
        padding: var(--spacing-sm) 0;
    }

    .header.scrolled .header-logo {
        height: 2.5rem;
    }

    .header.scrolled .header-title {
        font-size: 1.5rem;
    }

    .header.scrolled .header-subtitle {
        font-size: 0.9rem;
    }
}

@media (min-width: 1024px) {
    .header {
        padding: var(--spacing-lg) 0;
    }

    .header-title {
        font-size: 2.25rem;
    }

    .header-logo {
        height: 5.5rem;
    }

    .header-subtitle {
        font-size: 1.1rem;
    }

    .header.scrolled .header-logo {
        height: 3rem;
    }

    .header.scrolled .header-title {
        font-size: 1.75rem;
    }
}

/* ===============================================
   Main Content
   =============================================== */

.main {
    padding: var(--spacing-lg) 0;
    min-height: calc(100vh - 300px);
}

@media (min-width: 640px) {
    .main {
        padding: var(--spacing-xl) 0;
    }
}

/* ===============================================
   Introduction Section
   =============================================== */

.intro-section {
    margin-bottom: var(--spacing-lg);
}

.intro-card {
    background: linear-gradient(135deg, var(--color-accent-light) 0%, var(--color-accent) 100%);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    box-shadow: var(--shadow-md);
    border: 2px solid var(--color-accent);
}

.intro-text {
    color: var(--color-primary-dark);
    font-size: 1rem;
    font-weight: 500;
    text-align: center;
    font-style: italic;
}

@media (min-width: 640px) {
    .intro-card {
        padding: var(--spacing-lg);
    }

    .intro-text {
        font-size: 1.1rem;
    }
}

/* ===============================================
   Search Section
   =============================================== */

.search-section {
    margin-bottom: var(--spacing-lg);
}

.search-container {
    max-width: 600px;
    margin: 0 auto;
}

.search-box {
    position: relative;
    display: flex;
    align-items: center;
    background: var(--color-bg-secondary);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-full);
    padding: var(--spacing-xs) var(--spacing-md);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-base);
}

.search-box:focus-within {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(45, 90, 74, 0.1);
}

.search-icon {
    width: 20px;
    height: 20px;
    color: var(--color-text-muted);
    flex-shrink: 0;
}

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

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

.search-clear {
    background: transparent;
    border: none;
    padding: var(--spacing-xs);
    cursor: pointer;
    color: var(--color-text-muted);
    display: none;
    transition: color var(--transition-fast);
}

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

.search-clear svg {
    width: 20px;
    height: 20px;
}

.search-clear.active {
    display: block;
}

.search-stats {
    text-align: center;
    margin-top: var(--spacing-sm);
    font-size: 0.9rem;
    color: var(--color-text-secondary);
}

@media (min-width: 640px) {
    .search-box {
        padding: var(--spacing-sm) var(--spacing-lg);
    }

    .search-icon {
        width: 24px;
        height: 24px;
    }

    .search-input {
        font-size: 1.1rem;
    }
}

/* ===============================================
   Alphabet Filter
   =============================================== */

.alphabet-section {
    margin-bottom: var(--spacing-lg);
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.alphabet-container {
    display: flex;
    gap: var(--spacing-xs);
    justify-content: center;
    flex-wrap: wrap;
    padding: var(--spacing-xs) 0;
}

.alphabet-btn {
    background: var(--color-bg-secondary);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-sm);
    padding: var(--spacing-xs) var(--spacing-sm);
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--color-text);
    cursor: pointer;
    transition: all var(--transition-base);
    min-width: 38px;
    text-align: center;
}

.alphabet-btn:hover {
    background: var(--color-surface);
    border-color: var(--color-primary-light);
    transform: translateY(-2px);
}

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

.alphabet-btn.disabled {
    opacity: 0.4;
    cursor: not-allowed;
    pointer-events: none;
}

@media (min-width: 640px) {
    .alphabet-btn {
        padding: var(--spacing-sm) var(--spacing-md);
        font-size: 1rem;
        min-width: 44px;
    }
}

/* ===============================================
   Terms Grid
   =============================================== */

.terms-section {
    margin-bottom: var(--spacing-xl);
}

.terms-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-md);
}

@media (min-width: 640px) {
    .terms-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .terms-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

/* Term Card */
.term-card {
    background: var(--color-bg-secondary);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    cursor: pointer;
    transition: all var(--transition-base);
    position: relative;
    overflow: hidden;
    min-height: 200px;
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
}

/* Background illustration */
.term-bg-image {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    opacity: 0.6;
    transition: opacity var(--transition-base), transform var(--transition-base);
    z-index: 0;
}

.term-card:hover .term-bg-image {
    opacity: 0.8;
    transform: scale(1.05);
}

/* Content overlay for readability */
.term-bg-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(to top, rgba(255, 255, 255, 0.95) 0%, rgba(255, 255, 255, 0.85) 50%, rgba(255, 255, 255, 0.75) 100%);
    z-index: 1;
    transition: background var(--transition-base);
}

.term-card:hover .term-bg-overlay {
    background: linear-gradient(to top, rgba(255, 255, 255, 0.92) 0%, rgba(255, 255, 255, 0.8) 50%, rgba(255, 255, 255, 0.7) 100%);
}

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

.term-card:active {
    transform: translateY(-2px);
}

.term-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
    position: relative;
    z-index: 2;
}

.term-letter {
    background: var(--color-primary);
    color: white;
    width: 36px;
    height: 36px;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.1rem;
    flex-shrink: 0;
}

.term-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--color-text);
    flex: 1;
    position: relative;
    z-index: 2;
}

.term-definition {
    color: var(--color-text-secondary);
    font-size: 0.95rem;
    line-height: 1.5;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
    position: relative;
    z-index: 2;
}

@media (min-width: 640px) {
    .term-card {
        padding: var(--spacing-lg);
    }

    .term-letter {
        width: 40px;
        height: 40px;
        font-size: 1.2rem;
    }

    .term-title {
        font-size: 1.35rem;
    }

    .term-definition {
        font-size: 1rem;
    }
}

/* Term Illustration - Now hidden as background is used instead */
.term-illustration {
    display: none;
}

.modal-illustration {
    width: 100%;
    max-width: 100%;
    height: 300px;
    margin: 0 auto var(--spacing-lg);
    opacity: 0.8;
    color: var(--color-primary);
    display: flex;
    align-items: center;
    justify-content: center;
}

.modal-illustration svg {
    width: 100%;
    height: 100%;
}

.modal-illustration img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    object-position: center;
}

@media (min-width: 640px) {
    .modal-illustration {
        max-width: 100%;
        height: 400px;
    }
}

/* No Results */
.no-results {
    text-align: center;
    padding: var(--spacing-2xl) var(--spacing-lg);
    color: var(--color-text-muted);
}

.no-results-icon {
    width: 64px;
    height: 64px;
    margin: 0 auto var(--spacing-md);
    opacity: 0.5;
}

.no-results h3 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-sm);
    color: var(--color-text);
}

.no-results p {
    font-size: 1rem;
}

/* ===============================================
   Modal
   =============================================== */

.modal {
    position: fixed;
    inset: 0;
    z-index: 1000;
    display: none;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-md);
}

.modal.active {
    display: flex;
}

.modal-backdrop {
    position: absolute;
    inset: 0;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
    animation: fadeIn var(--transition-base);
}

.modal-content {
    position: relative;
    background: var(--color-bg-secondary);
    border-radius: var(--radius-xl);
    max-width: 600px;
    width: 100%;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: var(--shadow-xl);
    animation: slideUp var(--transition-slow);
}

.modal-close {
    position: absolute;
    top: var(--spacing-md);
    right: var(--spacing-md);
    background: var(--color-surface);
    border: none;
    border-radius: var(--radius-full);
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    color: var(--color-text);
    transition: all var(--transition-base);
    z-index: 10;
}

.modal-close:hover {
    background: var(--color-border);
    transform: rotate(90deg);
}

.modal-close svg {
    width: 20px;
    height: 20px;
}

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

.modal-header {
    margin-bottom: var(--spacing-lg);
}

.modal-letter {
    background: var(--color-primary);
    color: white;
    width: 56px;
    height: 56px;
    border-radius: var(--radius-md);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.75rem;
    margin-bottom: var(--spacing-md);
}

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

.modal-definition {
    background: var(--color-surface);
    border-left: 4px solid var(--color-primary);
    padding: var(--spacing-lg);
    border-radius: var(--radius-md);
}

.modal-definition p {
    font-size: 1.1rem;
    line-height: 1.7;
    color: var(--color-text);
}

@media (min-width: 640px) {
    .modal {
        padding: var(--spacing-lg);
    }

    .modal-body {
        padding: var(--spacing-2xl);
    }

    .modal-title {
        font-size: 2.5rem;
    }

    .modal-definition p {
        font-size: 1.15rem;
    }
}

/* ===============================================
   Footer
   =============================================== */

.footer {
    background: var(--color-primary-dark);
    color: white;
    padding: var(--spacing-lg) 0;
    margin-top: var(--spacing-2xl);
}

.footer-text {
    text-align: center;
    margin-bottom: var(--spacing-xs);
    font-weight: 500;
}

.footer-count {
    text-align: center;
    opacity: 0.8;
    font-size: 0.9rem;
}

/* ===============================================
   Loading Indicator
   =============================================== */

.loading {
    position: fixed;
    inset: 0;
    background: var(--color-bg);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: 2000;
    transition: opacity var(--transition-slow);
}

.loading.hidden {
    opacity: 0;
    pointer-events: none;
}

.loading-spinner {
    width: 48px;
    height: 48px;
    border: 4px solid var(--color-border);
    border-top-color: var(--color-primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
    margin-bottom: var(--spacing-md);
}

.loading p {
    color: var(--color-text-secondary);
    font-weight: 500;
}

/* ===============================================
   Animations
   =============================================== */

@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

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

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

/* ===============================================
   Utility Classes
   =============================================== */

.hidden {
    display: none !important;
}

/* Scrollbar Styling */
::-webkit-scrollbar {
    width: 10px;
    height: 10px;
}

::-webkit-scrollbar-track {
    background: var(--color-surface);
}

::-webkit-scrollbar-thumb {
    background: var(--color-primary-light);
    border-radius: var(--radius-sm);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--color-primary);
}

/* ===============================================
   Accessibility
   =============================================== */

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

/* Focus visible for keyboard navigation */
button:focus-visible,
.term-card:focus-visible {
    outline: 3px solid var(--color-primary);
    outline-offset: 2px;
}

/* Remove outline from search input as it's handled by .search-box:focus-within */
.search-input:focus,
.search-input:focus-visible {
    outline: none;
}