/* ============================================================
   SimInTech Materials — Main Stylesheet
   ============================================================ */

/* ----- Reset & base ----- */
*, *::before, *::after { box-sizing: border-box; }

:root {
    --color-bg: #f7f8fb;
    --color-surface: #ffffff;
    --color-text: #1a1f2e;
    --color-text-muted: #5b6478;
    --color-border: #e5e8ef;
    --color-primary: #2f6df4;
    --color-primary-dark: #1f55cc;
    --color-accent: #6c4cf1;
    --color-success: #16a34a;
    --color-shadow: 0 4px 14px rgba(20, 30, 60, 0.06);
    --color-shadow-hover: 0 12px 28px rgba(20, 30, 60, 0.12);
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --transition: 0.2s ease;
    --container: 1200px;
}

html, body {
    margin: 0;
    padding: 0;
    background: var(--color-bg);
    color: var(--color-text);
    font-family: 'Inter', system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
    font-size: 16px;
    line-height: 1.55;
    -webkit-font-smoothing: antialiased;
}

body {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

main { flex: 1; }

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

a { color: var(--color-primary); text-decoration: none; }
a:hover { text-decoration: underline; }

h1, h2, h3, h4 { margin: 0 0 0.5em; font-weight: 600; line-height: 1.25; color: var(--color-text); }
h1 { font-size: 2.25rem; }
h2 { font-size: 1.6rem; }
h3 { font-size: 1.15rem; }
p  { margin: 0 0 1em; }

.container {
    width: 100%;
    max-width: var(--container);
    margin: 0 auto;
    padding: 0 24px;
}

/* ----- Header ----- */
.site-header {
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    position: sticky;
    top: 0;
    z-index: 50;
    backdrop-filter: saturate(180%) blur(8px);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
    gap: 16px;
}

.logo {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
    font-size: 1.15rem;
    color: var(--color-text);
}
.logo:hover { text-decoration: none; }
.logo i { color: var(--color-primary); font-size: 1.4rem; }

.main-nav { display: flex; gap: 4px; }

.nav-link {
    display: inline-block;
    padding: 8px 14px;
    border-radius: var(--radius-sm);
    color: var(--color-text-muted);
    font-weight: 500;
    transition: background var(--transition), color var(--transition);
}
.nav-link:hover { background: var(--color-bg); color: var(--color-text); text-decoration: none; }
.nav-link.active { background: rgba(47, 109, 244, 0.1); color: var(--color-primary); }

.header-tools {
    display: flex;
    align-items: center;
    gap: 8px;
}

.lang-switcher {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 6px 10px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    color: var(--color-text-muted);
    font-size: 0.875rem;
    cursor: pointer;
    user-select: none;
    transition: border-color var(--transition);
}
.lang-switcher:hover { border-color: var(--color-primary); color: var(--color-primary); }

.nav-toggle {
    display: none;
    background: none;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    padding: 6px 10px;
    cursor: pointer;
    color: var(--color-text);
    font-size: 1rem;
}

/* ----- Hero / Page header ----- */
.hero {
    padding: 64px 0 48px;
    background: linear-gradient(180deg, #ffffff 0%, var(--color-bg) 100%);
}
.hero h1 { font-size: 2.6rem; margin-bottom: 12px; }
.hero-subtitle { font-size: 1.1rem; color: var(--color-text-muted); max-width: 720px; }

.page-header {
    padding: 40px 0 24px;
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
}
.page-header h1 { margin-bottom: 6px; }
.page-header p { color: var(--color-text-muted); margin: 0; }

/* ----- Section ----- */
.section { padding: 40px 0 64px; }
.section-title { margin-bottom: 24px; font-size: 1.4rem; }

/* ----- Home: section grid ----- */
.section-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 24px;
}

.section-card {
    display: flex;
    flex-direction: column;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: 28px;
    color: var(--color-text);
    box-shadow: var(--color-shadow);
    transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
}
.section-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--color-shadow-hover);
    border-color: rgba(47, 109, 244, 0.3);
    text-decoration: none;
}
.section-card h3 { margin-top: 16px; }
.section-card p { color: var(--color-text-muted); flex: 1; }

.section-icon {
    width: 56px;
    height: 56px;
    border-radius: var(--radius-md);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 1.6rem;
    color: #fff;
}
.section-icon--blue   { background: linear-gradient(135deg, #4f8df9, #2f6df4); }
.section-icon--green  { background: linear-gradient(135deg, #34d399, #10b981); }
.section-icon--purple { background: linear-gradient(135deg, #a78bfa, #6c4cf1); }

.section-card-link {
    margin-top: 12px;
    color: var(--color-primary);
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    gap: 6px;
    transition: gap var(--transition);
}
.section-card:hover .section-card-link { gap: 10px; }

/* ----- Filter bar ----- */
.filter-bar {
    display: flex;
    flex-direction: column;
    gap: 16px;
    margin-bottom: 28px;
    padding: 20px;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
}

.search-input {
    position: relative;
}
.search-input i {
    position: absolute;
    left: 14px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--color-text-muted);
}
.search-input input {
    width: 100%;
    padding: 12px 14px 12px 40px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    font: inherit;
    background: var(--color-bg);
    transition: border-color var(--transition), background var(--transition);
}
.search-input input:focus {
    outline: none;
    border-color: var(--color-primary);
    background: #fff;
}

.tag-filters {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}
.tag-filter {
    padding: 6px 12px;
    border: 1px solid var(--color-border);
    border-radius: 999px;
    background: var(--color-bg);
    color: var(--color-text-muted);
    font-size: 0.85rem;
    cursor: pointer;
    transition: all var(--transition);
}
.tag-filter:hover { border-color: var(--color-primary); color: var(--color-primary); }
.tag-filter.active {
    background: var(--color-primary);
    border-color: var(--color-primary);
    color: #fff;
}

/* ----- Status messages ----- */
.status-message {
    margin: 12px 0;
    padding: 14px;
    border-radius: var(--radius-sm);
    text-align: center;
    color: var(--color-text-muted);
    font-size: 0.95rem;
    display: none;
}
.status-message.visible { display: block; }
.status-message.error {
    background: #fff1f1;
    color: #c83232;
    border: 1px solid #f5cccc;
}

/* ----- Card grid ----- */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 24px;
}

.card {
    display: flex;
    flex-direction: column;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    overflow: hidden;
    box-shadow: var(--color-shadow);
    transition: transform var(--transition), box-shadow var(--transition);
}
.card:hover { transform: translateY(-3px); box-shadow: var(--color-shadow-hover); }

.card-media {
    aspect-ratio: 16 / 9;
    background: #0d1220;
    position: relative;
    overflow: hidden;
}
.card-media iframe,
.card-media img {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    border: 0;
    object-fit: cover;
}

.card-thumb-fallback {
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    color: rgba(255,255,255,0.7);
    font-size: 2.5rem;
    background: linear-gradient(135deg, #1f2a44, #0d1220);
}

.card-body {
    padding: 18px 20px 20px;
    display: flex;
    flex-direction: column;
    flex: 1;
    gap: 10px;
}
.card-title { font-size: 1.05rem; font-weight: 600; margin: 0; }
.card-desc {
    color: var(--color-text-muted);
    font-size: 0.92rem;
    margin: 0;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}
.card-desc.expanded {
    -webkit-line-clamp: unset;
    overflow: visible;
}
.card-readmore {
    background: none;
    border: none;
    padding: 0;
    color: var(--color-primary);
    font: inherit;
    font-size: 0.85rem;
    cursor: pointer;
    align-self: flex-start;
}
.card-readmore:hover { text-decoration: underline; }

.card-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
}
.card-tag {
    padding: 3px 10px;
    border-radius: 999px;
    background: rgba(47, 109, 244, 0.08);
    color: var(--color-primary);
    font-size: 0.75rem;
    font-weight: 500;
}

.card-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: var(--color-text-muted);
    font-size: 0.8rem;
}

.card-actions {
    margin-top: auto;
    display: flex;
    gap: 8px;
}

/* ----- Buttons ----- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 10px 16px;
    border-radius: var(--radius-sm);
    border: 1px solid transparent;
    font: inherit;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition);
    text-decoration: none;
}
.btn-primary {
    background: var(--color-primary);
    color: #fff;
}
.btn-primary:hover {
    background: var(--color-primary-dark);
    text-decoration: none;
}
.btn-secondary {
    background: var(--color-bg);
    color: var(--color-text);
    border-color: var(--color-border);
}
.btn-secondary:hover {
    border-color: var(--color-primary);
    color: var(--color-primary);
    text-decoration: none;
}
.btn-block { width: 100%; }

/* ----- Modal ----- */
.modal {
    position: fixed;
    inset: 0;
    z-index: 100;
    display: none;
    align-items: center;
    justify-content: center;
    padding: 20px;
}
.modal.open { display: flex; }
.modal-overlay {
    position: absolute;
    inset: 0;
    background: rgba(15, 22, 40, 0.55);
    backdrop-filter: blur(2px);
}
.modal-dialog {
    position: relative;
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    max-width: 720px;
    width: 100%;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: 0 30px 60px rgba(0,0,0,0.25);
    animation: modalIn 0.18s ease;
}
@keyframes modalIn {
    from { opacity: 0; transform: translateY(8px) scale(0.98); }
    to   { opacity: 1; transform: none; }
}

.modal-close {
    position: absolute;
    top: 12px;
    right: 12px;
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: 50%;
    width: 36px;
    height: 36px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    color: var(--color-text);
    transition: background var(--transition), color var(--transition);
}
.modal-close:hover { background: var(--color-primary); color: #fff; border-color: var(--color-primary); }

.modal-content { padding: 32px 28px 28px; }
.modal-content h2 { margin-bottom: 6px; padding-right: 40px; }
.modal-meta {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
    color: var(--color-text-muted);
    font-size: 0.85rem;
    margin-bottom: 18px;
}
.modal-meta span {
    display: inline-flex;
    align-items: center;
    gap: 6px;
}

.modal-screenshots {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin: 18px 0;
}
.modal-screenshots img {
    width: 200px;
    max-width: 100%;
    height: auto;
    border-radius: var(--radius-sm);
    border: 1px solid var(--color-border);
    cursor: zoom-in;
    transition: transform var(--transition);
}
.modal-screenshots img:hover { transform: scale(1.03); }

/* ----- Footer ----- */
.site-footer {
    background: var(--color-surface);
    border-top: 1px solid var(--color-border);
    padding: 20px 0;
    text-align: center;
    color: var(--color-text-muted);
    font-size: 0.875rem;
}

/* ----- Responsive ----- */
@media (max-width: 900px) {
    .main-nav {
        position: absolute;
        top: 64px;
        right: 16px;
        background: var(--color-surface);
        flex-direction: column;
        padding: 12px;
        border: 1px solid var(--color-border);
        border-radius: var(--radius-md);
        box-shadow: var(--color-shadow);
        display: none;
        min-width: 180px;
    }
    .main-nav.open { display: flex; }
    .nav-toggle { display: inline-flex; }
}

@media (max-width: 768px) {
    h1 { font-size: 1.8rem; }
    .hero { padding: 40px 0 32px; }
    .hero h1 { font-size: 2rem; }
    .card-grid { grid-template-columns: 1fr; }
    .section-grid { grid-template-columns: 1fr; }
    .modal-dialog { max-height: 95vh; border-radius: var(--radius-md); }
    .modal-content { padding: 24px 20px; }
}

@media (min-width: 769px) and (max-width: 1100px) {
    .card-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (min-width: 1300px) {
    .card-grid { grid-template-columns: repeat(4, 1fr); }
}