/* ============================================================
   AppWise Education Landing — Main Stylesheet
   Dark navy theme · Cyan accents · Mobile-first
   ============================================================ */

/* ── Custom Properties ─────────────────────────────────────── */
:root {
    /* Palette */
    --color-bg:          #080f1e;
    --color-bg-2:        #0c1528;
    --color-bg-card:     #0f1c35;
    --color-bg-card-h:   #132140;
    --color-border:      rgba(255,255,255,0.07);
    --color-border-cyan: rgba(0,209,255,0.25);

    --color-cyan:        #00d1ff;
    --color-cyan-dim:    rgba(0,209,255,0.15);
    --color-cyan-glow:   rgba(0,209,255,0.08);
    --color-white:       #ffffff;
    --color-text:        rgba(255,255,255,0.82);
    --color-text-muted:  rgba(255,255,255,0.48);

    /* Grid overlay */
    --grid-color:        rgba(255,255,255,0.028);
    --grid-size:         44px;

    /* Typography */
    --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Helvetica Neue',
                 Arial, 'Noto Sans', 'Liberation Sans', sans-serif,
                 'Apple Color Emoji', 'Segoe UI Emoji';
    --font-cjk:  'PingFang SC', 'Hiragino Sans GB', 'Noto Sans CJK SC',
                 'Microsoft YaHei', 'WenQuanYi Micro Hei', var(--font-sans);

    /* Spacing */
    --space-xs:  0.5rem;
    --space-sm:  1rem;
    --space-md:  1.5rem;
    --space-lg:  2.5rem;
    --space-xl:  4rem;
    --space-2xl: 6rem;

    /* Layout */
    --container-max: 1120px;
    --container-px:  1.25rem;
    --radius-sm:     8px;
    --radius-md:     12px;
    --radius-lg:     16px;

    /* Transitions */
    --ease: cubic-bezier(0.25, 0.46, 0.45, 0.94);
    --dur:  200ms;
}

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

html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: var(--font-sans);
    font-size: 1rem;
    line-height: 1.65;
    color: var(--color-text);
    background-color: var(--color-bg);
    overflow-x: hidden;

    /* Subtle grid texture */
    background-image:
        linear-gradient(var(--grid-color) 1px, transparent 1px),
        linear-gradient(90deg, var(--grid-color) 1px, transparent 1px);
    background-size: var(--grid-size) var(--grid-size);
}

/* CJK language font override */
:lang(zh), :lang(ja), :lang(ko) {
    font-family: var(--font-cjk);
}

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

a {
    color: var(--color-cyan);
    text-decoration: none;
    transition: opacity var(--dur) var(--ease);
}
a:hover { opacity: 0.8; }

ul { list-style: none; }

/* ── Container ──────────────────────────────────────────────── */
.container {
    width: 100%;
    max-width: var(--container-max);
    margin-inline: auto;
    padding-inline: var(--container-px);
}

/* ── Buttons ────────────────────────────────────────────────── */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.6rem 1.25rem;
    font-size: 0.9rem;
    font-weight: 600;
    font-family: inherit;
    border-radius: var(--radius-sm);
    border: 1.5px solid transparent;
    cursor: pointer;
    white-space: nowrap;
    transition: background var(--dur) var(--ease),
                color var(--dur) var(--ease),
                border-color var(--dur) var(--ease),
                box-shadow var(--dur) var(--ease),
                transform var(--dur) var(--ease);
    text-decoration: none;
    line-height: 1.4;
}

.btn:focus-visible {
    outline: 2px solid var(--color-cyan);
    outline-offset: 3px;
}

/* Primary — cyan fill */
.btn-primary {
    background: var(--color-cyan);
    color: #050d1d;
    border-color: var(--color-cyan);
}
.btn-primary:hover {
    background: #29d9ff;
    border-color: #29d9ff;
    box-shadow: 0 0 18px rgba(0,209,255,0.35);
    transform: translateY(-1px);
    opacity: 1;
}

/* Ghost — bordered */
.btn-ghost {
    background: transparent;
    color: var(--color-text);
    border-color: var(--color-border);
}
.btn-ghost:hover {
    border-color: var(--color-cyan);
    color: var(--color-cyan);
    background: var(--color-cyan-glow);
    opacity: 1;
}

/* Large variant */
.btn-lg {
    padding: 0.8rem 2rem;
    font-size: 1rem;
}

/* ── Site Header ────────────────────────────────────────────── */
.site-header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(8, 15, 30, 0.88);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--color-border);
}

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

.header-logo {
    flex-shrink: 0;
    opacity: 1;
    transition: opacity var(--dur) var(--ease);
}
.header-logo:hover { opacity: 0.85; }
.header-logo img { height: 34px; width: auto; }

.header-actions {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    flex-shrink: 0;
}

/* ── Language Switcher ──────────────────────────────────────── */
.lang-switcher {
    position: relative;
}

.lang-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.3rem;
    background: transparent;
    border: 1.5px solid var(--color-border);
    color: var(--color-text-muted);
    padding: 0.4rem 0.65rem;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-family: inherit;
    font-size: 0.82rem;
    font-weight: 600;
    letter-spacing: 0.04em;
    transition: border-color var(--dur) var(--ease),
                color var(--dur) var(--ease),
                background var(--dur) var(--ease);
}
.lang-btn:hover,
.lang-btn[aria-expanded="true"] {
    border-color: var(--color-cyan);
    color: var(--color-cyan);
    background: var(--color-cyan-glow);
}
.lang-btn:focus-visible {
    outline: 2px solid var(--color-cyan);
    outline-offset: 2px;
}

.lang-globe {
    flex-shrink: 0;
    opacity: 0.7;
}

.lang-chevron {
    transition: transform var(--dur) var(--ease);
    flex-shrink: 0;
}
.lang-btn[aria-expanded="true"] .lang-chevron {
    transform: rotate(180deg);
}

/* 3-column grid dropdown — no scroll */
.lang-dropdown {
    position: absolute;
    top: calc(100% + 6px);
    right: 0;
    width: 162px;                       /* 3 × 50px cells + gaps + padding */
    background: #0b1829;
    border: 1px solid rgba(0,209,255,0.18);
    border-radius: var(--radius-md);
    box-shadow: 0 16px 40px rgba(0,0,0,0.55);
    padding: 0.45rem;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 0.2rem;
    overflow: hidden;                   /* never scrolls */
    opacity: 0;
    visibility: hidden;
    transform: translateY(-6px);
    transition: opacity var(--dur) var(--ease),
                transform var(--dur) var(--ease),
                visibility 0s var(--dur);
}

.lang-dropdown.is-open {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
    transition: opacity var(--dur) var(--ease),
                transform var(--dur) var(--ease),
                visibility 0s 0s;
}

/* Each language cell */
.lang-cell {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0.38rem 0.2rem;
    border-radius: 6px;
    font-size: 0.72rem;
    font-weight: 700;
    letter-spacing: 0.05em;
    color: var(--color-text-muted);
    text-decoration: none;
    transition: background var(--dur) var(--ease), color var(--dur) var(--ease);
    text-align: center;
    white-space: nowrap;
}
.lang-cell:hover {
    background: var(--color-cyan-glow);
    color: var(--color-cyan);
    opacity: 1;
}
.lang-cell--active {
    background: rgba(0,209,255,0.14);
    color: var(--color-cyan);
}
.lang-cell:focus-visible {
    outline: 2px solid var(--color-cyan);
    outline-offset: -2px;
}

/* ── Hero ───────────────────────────────────────────────────── */
.hero {
    padding-top: var(--space-xl);
    padding-bottom: var(--space-xl);
    position: relative;
    overflow: hidden;
}

/* Radial glow behind hero */
.hero::before {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(ellipse 60% 55% at 50% -5%, rgba(0,209,255,0.07) 0%, transparent 70%);
    pointer-events: none;
}

.hero-inner {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--space-xl);
    align-items: center;
}

@media (min-width: 860px) {
    .hero-inner {
        grid-template-columns: 1fr 1fr;
        gap: var(--space-lg);
    }
}

.hero-copy {
    max-width: 580px;
}

.hero-title {
    font-size: clamp(1.75rem, 4vw, 2.75rem);
    font-weight: 700;
    line-height: 1.2;
    color: var(--color-white);
    letter-spacing: -0.02em;
    margin-bottom: var(--space-sm);
}

.hero-desc {
    font-size: clamp(0.95rem, 1.8vw, 1.05rem);
    color: var(--color-text-muted);
    line-height: 1.75;
    margin-bottom: var(--space-md);
    max-width: 500px;
}

.hero-btns {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin-bottom: var(--space-lg);
}

/* Feature tags */
.hero-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.hero-tag {
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    background: var(--color-cyan-glow);
    border: 1px solid var(--color-border-cyan);
    color: var(--color-text-muted);
    font-size: 0.78rem;
    font-weight: 500;
    padding: 0.25rem 0.65rem;
    border-radius: 100px;
    letter-spacing: 0.01em;
}

.hero-tag-dot {
    width: 5px;
    height: 5px;
    border-radius: 50%;
    background: var(--color-cyan);
    flex-shrink: 0;
}

/* ── Hero Illustration — CSS Panel Mock ─────────────────────── */
.hero-illustration {
    display: flex;
    justify-content: center;
    align-items: flex-start;
}

.panel-mock {
    width: 100%;
    max-width: 440px;
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: 0 24px 60px rgba(0,0,0,0.4), 0 0 0 1px rgba(0,209,255,0.06);
}

/* Window bar */
.panel-mock__bar {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.7rem 1rem;
    background: rgba(255,255,255,0.03);
    border-bottom: 1px solid var(--color-border);
}
.panel-mock__dot {
    width: 9px;
    height: 9px;
    border-radius: 50%;
    flex-shrink: 0;
}
.panel-mock__dot--red    { background: #ff5f56; }
.panel-mock__dot--yellow { background: #ffbd2e; }
.panel-mock__dot--green  { background: #27c93f; }

.panel-mock__title {
    margin-left: 0.5rem;
    font-size: 0.72rem;
    color: var(--color-text-muted);
    font-weight: 500;
    letter-spacing: 0.04em;
}

/* Body: sidebar + main */
.panel-mock__body {
    display: flex;
    height: 240px;
}

.panel-mock__sidebar {
    width: 40px;
    background: rgba(255,255,255,0.02);
    border-right: 1px solid var(--color-border);
    padding: 0.75rem 0.5rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    align-items: center;
}

.panel-mock__nav-item {
    display: block;
    width: 22px;
    height: 5px;
    background: rgba(255,255,255,0.12);
    border-radius: 3px;
}
.panel-mock__nav-item--active {
    background: var(--color-cyan);
    box-shadow: 0 0 8px rgba(0,209,255,0.5);
}

.panel-mock__main {
    flex: 1;
    padding: 0.75rem;
    display: flex;
    flex-direction: column;
    gap: 0.65rem;
    overflow: hidden;
}

/* Stats row */
.panel-mock__stats {
    display: flex;
    gap: 0.5rem;
}
.panel-mock__stat {
    flex: 1;
    background: rgba(255,255,255,0.03);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    padding: 0.4rem 0.5rem;
}
.panel-mock__stat-num {
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--color-cyan);
    line-height: 1.2;
}
.panel-mock__stat-label {
    height: 4px;
    background: rgba(255,255,255,0.08);
    border-radius: 2px;
    margin-top: 0.25rem;
    width: 70%;
}

/* Schedule grid */
.panel-mock__schedule {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}
.panel-mock__schedule-header {
    display: flex;
    gap: 0.25rem;
}
.panel-mock__schedule-header span {
    flex: 1;
    height: 4px;
    background: rgba(255,255,255,0.07);
    border-radius: 2px;
}
.panel-mock__schedule-row {
    display: flex;
    gap: 0.25rem;
}
.panel-mock__slot {
    flex: 1;
    height: 18px;
    border-radius: 3px;
    background: rgba(255,255,255,0.03);
    border: 1px solid var(--color-border);
}
.panel-mock__slot--filled {
    background: rgba(255,255,255,0.08);
    border-color: rgba(255,255,255,0.1);
}
.panel-mock__slot--accent {
    background: rgba(0,209,255,0.18);
    border-color: rgba(0,209,255,0.35);
}

/* Attendance bars */
.panel-mock__attendance {
    display: flex;
    flex-direction: column;
    gap: 0.3rem;
}
.panel-mock__att-bar {
    height: 5px;
    background: var(--color-cyan);
    border-radius: 3px;
    opacity: 0.75;
}
.panel-mock__att-bar--dim {
    background: rgba(0,209,255,0.35);
    opacity: 1;
}

/* ── Section Title ──────────────────────────────────────────── */
.section-title {
    font-size: clamp(1.35rem, 3vw, 1.9rem);
    font-weight: 700;
    color: var(--color-white);
    text-align: center;
    margin-bottom: var(--space-lg);
    letter-spacing: -0.01em;
}

/* ── Features Section ───────────────────────────────────────── */
.features {
    padding-block: var(--space-2xl);
    position: relative;
}

/* Thin separator line above features */
.features::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: min(700px, 90%);
    height: 1px;
    background: linear-gradient(90deg,
        transparent 0%,
        var(--color-border-cyan) 30%,
        var(--color-border-cyan) 70%,
        transparent 100%);
}

.features-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--space-sm);
}

@media (min-width: 600px) {
    .features-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (min-width: 900px) {
    .features-grid { grid-template-columns: repeat(4, 1fr); }
}

/* Feature card */
.feat-card {
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--space-md);
    transition: border-color var(--dur) var(--ease),
                background var(--dur) var(--ease),
                transform var(--dur) var(--ease),
                box-shadow var(--dur) var(--ease);
}

.feat-card:hover {
    border-color: var(--color-border-cyan);
    background: var(--color-bg-card-h);
    transform: translateY(-2px);
    box-shadow: 0 8px 28px rgba(0,0,0,0.25);
}

.feat-card__icon {
    width: 42px;
    height: 42px;
    background: var(--color-cyan-glow);
    border: 1px solid var(--color-border-cyan);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-cyan);
    margin-bottom: 0.85rem;
    flex-shrink: 0;
}

.feat-card__title {
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--color-white);
    margin-bottom: 0.45rem;
    line-height: 1.35;
}

.feat-card__desc {
    font-size: 0.85rem;
    color: var(--color-text-muted);
    line-height: 1.7;
}

/* ── CTA Section ────────────────────────────────────────────── */
.cta-section {
    padding-block: var(--space-2xl);
    position: relative;
}

.cta-section::before {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(ellipse 55% 65% at 50% 50%, rgba(0,209,255,0.055) 0%, transparent 70%);
    pointer-events: none;
}

.cta-section::after {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: min(700px, 90%);
    height: 1px;
    background: linear-gradient(90deg,
        transparent 0%,
        var(--color-border-cyan) 30%,
        var(--color-border-cyan) 70%,
        transparent 100%);
}

.cta-inner {
    text-align: center;
    position: relative;
    z-index: 1;
}

.cta-title {
    font-size: clamp(1.2rem, 2.8vw, 1.75rem);
    font-weight: 700;
    color: var(--color-white);
    margin-bottom: var(--space-md);
    letter-spacing: -0.015em;
    max-width: 600px;
    margin-inline: auto;
    margin-bottom: var(--space-md);
}

/* ── Site Footer ────────────────────────────────────────────── */
.site-footer {
    border-top: 1px solid var(--color-border);
    padding-block: var(--space-lg);
    background: var(--color-bg-2);
}

.footer-inner {
    display: flex;
    flex-direction: row;
    align-items: center;
    gap: 1.5rem;
    flex-wrap: wrap;
}

.footer-meta {
    display: flex;
    flex-direction: row;
    align-items: center;
    gap: 0.75rem;
    flex-wrap: wrap;
}

.footer-logo {
    opacity: 0.85;
    transition: opacity var(--dur) var(--ease);
}
.footer-logo:hover { opacity: 1; }
.footer-logo img { height: 28px; width: auto; }

.footer-tagline {
    font-size: 0.82rem;
    color: var(--color-text-muted);
    max-width: 480px;
    text-align: left;
}

.footer-sep {
    color: rgba(255,255,255,0.2);
    font-size: 0.8rem;
    flex-shrink: 0;
}

.footer-copy {
    font-size: 0.8rem;
    color: rgba(255,255,255,0.3);
    text-align: left;
    white-space: nowrap;
}
.footer-copy a {
    color: rgba(255,255,255,0.4);
}
.footer-copy a:hover {
    color: var(--color-cyan);
    opacity: 1;
}

/* ── Utility ────────────────────────────────────────────────── */
.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;
}

/* ── Responsive — narrow mobile (390px) ─────────────────────── */
@media (max-width: 480px) {
    :root {
        --container-px: 1rem;
    }

    .header-inner {
        height: 56px;
        gap: 0.5rem;
    }

    .header-logo img { height: 28px; }

    .header-actions {
        gap: 0.5rem;
    }

    /* Ensure nav_demo button text doesn't overflow */
    .header-actions .btn {
        padding: 0.5rem 0.75rem;
        font-size: 0.82rem;
    }

    .lang-btn {
        padding: 0.4rem 0.5rem;
    }

    .hero {
        padding-top: var(--space-lg);
        padding-bottom: var(--space-lg);
    }

    .hero-btns {
        flex-direction: column;
    }
    .hero-btns .btn {
        width: 100%;
        justify-content: center;
    }

    .feat-card {
        padding: var(--space-sm);
    }

    /* Hide illustration on very small screens */
    .hero-illustration {
        display: none;
    }

    /* Footer: stack vertically on mobile */
    .footer-inner {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.75rem;
    }
    .footer-meta {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.2rem;
    }
    .footer-sep {
        display: none;
    }
}

@media (min-width: 481px) and (max-width: 859px) {
    .panel-mock {
        max-width: 340px;
    }
}

/* ── Focus management ───────────────────────────────────────── */
:focus-visible {
    outline: 2px solid var(--color-cyan);
    outline-offset: 3px;
}