:root {
    --tshfeer-purple: #b135ff;
    --font-family-base: "Inter", "Segoe UI", Roboto, sans-serif;
    --font-family-display: "Inter", "Segoe UI", Roboto, sans-serif;
    --shadow-sm: 0 6px 16px rgba(12, 20, 44, 0.12);
    --shadow-md: 0 18px 40px rgba(11, 19, 41, 0.18);
    --shadow-lg: 0 28px 65px rgba(6, 12, 30, 0.24);
    --radius-sm: 0.5rem;
    --radius-md: 0.75rem;
    --radius-lg: 1.25rem;
    --transition-base: 180ms ease;
    --color-text: #0f1729;
    --color-text-secondary: #1f2937;
    --color-text-muted: #4b5563;
}

body[data-theme="dark"] {
    --color-bg: #050915;
    --color-surface: #0e152b;
    --color-surface-soft: #131d38;
    --color-surface-accent: #182645;
    --color-text: #ffffff;
    --color-text-secondary: #e1e7f7;
    --color-text-muted: #b0b7c3;
    --bs-body-color: #ffffff;
    --bs-body-color-rgb: 255, 255, 255;
    --bs-secondary-color: #b0b7c3;
    --bs-secondary-color-rgb: 176, 183, 195;
    --color-on-primary: #ffffff;
    --color-on-success: #ffffff;
    --color-on-warning: #160c02;
    --color-on-danger: #ffffff;
    --color-border: rgba(167, 182, 242, 0.1);
    --color-border-strong: rgba(167, 182, 242, 0.22);
    --color-primary: #5f7bff;
    --color-primary-strong: #7c97ff;
    --color-primary-soft: rgba(127, 155, 255, 0.18);
    --color-secondary: #4ddaff;
    --color-success: #2ddb8a;
    --color-warning: #ffc878;
    --color-danger: #ff7b8f;
    --color-info: #5ac8ff;
}

*, *::before, *::after {
    box-sizing: border-box;
}

html, body {
    height: 100%;
}

body {
    margin: 0;
    font-family: var(--font-family-base);
    background: linear-gradient(180deg, var(--color-bg) 0%, var(--color-bg) 100%);
    color: var(--color-text);
    line-height: 1.6;
    transition: background 220ms ease, color 220ms ease;
}

/* Ensure form text remains readable against dark backgrounds */
label {
    color: #ffffff !important;
}

input,
textarea,
select {
    color: #ffffff !important;
}

input::placeholder,
textarea::placeholder,
select::placeholder {
    color: rgba(255, 255, 255, 0.6) !important;
}

.form-control {
    color: #ffffff !important;
}

.form-control::placeholder {
    color: rgba(255, 255, 255, 0.6) !important;
}

img, svg {
    max-width: 100%;
}

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

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

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-family-display);
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 0.75rem;
    color: var(--color-text);
}

h1 {
    font-size: clamp(2.15rem, 2.9vw, 3rem);
    letter-spacing: -0.02em;
}

h2 {
    font-size: clamp(1.8rem, 2.5vw, 2.35rem);
}

h3 {
    font-size: clamp(1.5rem, 2vw, 1.9rem);
}

h4 {
    font-size: 1.35rem;
}

.course-learn-page {
    margin: 0 auto;
    padding: clamp(1.5rem, 3vw, 3rem);
    width: min(1400px, 98vw);
}

.course-learn-sidebar {
    position: sticky;
    top: 6.5rem;
}

.course-learn-list .list-group-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.75rem;
    border: none;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
    background-color: rgba(24, 24, 24, 0.7);
    color: var(--color-text);
}

.course-learn-list .list-group-item:first-child {
    border-radius: 0.75rem 0.75rem 0 0;
}

.course-learn-list .list-group-item:last-child {
    border-radius: 0 0 0.75rem 0.75rem;
    border-bottom: none;
}

.course-learn-list .active {
    background: linear-gradient(135deg, #2563eb, #1d4ed8);
    color: #fff;
    font-weight: 600;
}

.certificate-panel {
    margin-top: 1.5rem;
    padding: 1.25rem;
    border-radius: 1rem;
    background: linear-gradient(135deg, rgba(95, 123, 255, 0.28), rgba(177, 53, 255, 0.18));
    border: 1px solid rgba(127, 155, 255, 0.25);
    box-shadow: 0 24px 48px -32px rgba(10, 17, 38, 0.6);
}

.certificate-panel-title {
    margin: 0 0 0.35rem;
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--color-text);
}

.certificate-panel-subtitle {
    margin: 0 0 0.9rem;
    color: var(--color-text-secondary);
    font-size: 0.95rem;
}

.certificate-alert {
    margin-bottom: 0.85rem;
}

.certificate-form .form-control {
    background-color: rgba(4, 7, 18, 0.65);
    border: 1px solid rgba(127, 155, 255, 0.3);
    color: var(--color-text);
}

.certificate-form .form-control:focus {
    border-color: rgba(127, 155, 255, 0.65);
    box-shadow: 0 0 0 0.15rem rgba(127, 155, 255, 0.2);
}

.certificate-form .btn {
    font-weight: 600;
}

.certificate-holder-name {
    margin: 0 0 0.9rem;
    font-weight: 600;
    color: var(--color-text);
}

.certificate-panel .btn {
    font-weight: 600;
}

.course-learn-content {
    background: rgba(15, 15, 15, 0.75);
    border-radius: 1rem;
    padding: clamp(1.75rem, 3vw, 2.5rem);
    box-shadow: 0 30px 60px -45px rgba(15, 23, 42, 0.6);
    border: 1px solid rgba(37, 99, 235, 0.12);
}

.course-learn-header {
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
    padding-bottom: 1rem;
}

.course-learn-alert {
    border-radius: 0.75rem;
    padding: 0.75rem 1rem;
}

.course-learn-video {
    position: relative;
    width: 100%;
    padding-top: 56.25%;
    border-radius: 1rem;
    overflow: hidden;
    box-shadow: 0 25px 45px -30px rgba(37, 99, 235, 0.45);
    background: radial-gradient(circle at top, rgba(37, 99, 235, 0.35), rgba(15, 23, 42, 0.8));
}

.course-learn-video-frame {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    border: none;
    border-radius: inherit;
}

.course-learn-body {
    color: var(--color-text);
    line-height: 1.75;
    font-size: 1.05rem;
}

.course-learn-body p {
    margin-bottom: 1rem;
}

.course-learn-body ul,
.course-learn-body ol {
    padding-left: 1.25rem;
    margin-bottom: 1.25rem;
}

.course-learn-body a {
    color: #60a5fa;
    text-decoration: underline;
    text-decoration-color: rgba(96, 165, 250, 0.4);
}

@media (max-width: 1199.98px) {
    .course-learn-sidebar {
        position: static;
    }
}

@media (max-width: 767.98px) {
    .course-learn-page {
        padding: 1.5rem 1rem 2.5rem;
    }

    .course-learn-content {
        padding: 1.5rem;
    }
}

p {
    margin-top: 0;
    margin-bottom: 1rem;
    color: var(--color-text);
}

.text-muted {
    color: var(--color-text-muted) !important;
}

.table {
    --bs-table-color: var(--color-text-secondary);
    --bs-table-bg: rgba(10, 16, 30, 0.78);
    --bs-table-striped-color: var(--color-text);
    --bs-table-striped-bg: rgba(255, 255, 255, 0.04);
    --bs-table-hover-color: var(--color-text);
    --bs-table-hover-bg: rgba(92, 120, 255, 0.14);
    --bs-table-border-color: rgba(127, 155, 255, 0.16);
    color: var(--bs-table-color);
    border-color: var(--bs-table-border-color);
    border-radius: 1rem;
    overflow: hidden;
    background: var(--bs-table-bg);
    box-shadow: 0 18px 45px -38px rgba(9, 15, 32, 0.85);
}

.table thead,
.table thead.table-dark,
.table-dark {
    --bs-table-bg: rgba(18, 29, 56, 0.92);
    --bs-table-color: var(--color-text);
    background: linear-gradient(135deg, rgba(18, 29, 56, 0.92), rgba(9, 15, 32, 0.95));
    color: var(--color-text);
}

.table thead th {
    border-bottom-color: rgba(127, 155, 255, 0.24);
    font-weight: 700;
    letter-spacing: 0.04em;
    text-transform: uppercase;
}

.table > :not(caption) > * > * {
    box-shadow: inset 0 0 0 9999px rgba(0, 0, 0, 0);
    border-bottom-color: rgba(127, 155, 255, 0.12);
}

.table tbody tr:hover {
    color: var(--bs-table-hover-color);
}

.app-shell {
    min-height: 100%;
    display: flex;
    flex-direction: column;
}

.app-header {
    position: sticky;
    top: 0;
    z-index: 40;
    backdrop-filter: blur(16px);
    background: linear-gradient(90deg, rgba(9, 15, 28, 0.82), rgba(14, 22, 45, 0.78));
    border-bottom: 1px solid rgba(255, 255, 255, 0.04);
}

.app-header .navbar {
    padding: 0.85rem 0;
}

.app-header .navbar .container-fluid {
    padding-right: 1.25rem;
    padding-left: 1.25rem;
}

.navbar-toggler {
    border-color: rgba(255, 255, 255, 0.35);
}

.navbar-toggler:focus {
    box-shadow: 0 0 0 0.1rem rgba(255, 255, 255, 0.35);
}

.navbar-toggler-icon {
    background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 30 30'%3e%3cpath stroke='rgba(255, 255, 255, 0.94)' stroke-linecap='round' stroke-miterlimit='10' stroke-width='2' d='M4 7h22M4 15h22M4 23h22'/%3e%3c/svg%3e");
}

@media (min-width: 992px) {
    .app-header .navbar .container-fluid {
        padding-right: 1.75rem;
        padding-left: 1.75rem;
    }
}

.navbar-brand {
    display: inline-flex;
    align-items: center;
    gap: 0.65rem;
    font-size: 1.2rem;
    font-weight: 700;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--color-text);
}

.brand-badge {
    width: 2.5rem;
    height: 2.5rem;
    border-radius: 0.8rem;
    display: grid;
    place-items: center;
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
    color: var(--color-on-primary);
    font-weight: 700;
    font-size: 1rem;
    box-shadow: inset 0 0 12px rgba(255, 255, 255, 0.18);
}

.logo-wrapper {
    width: 44px;
    height: 44px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.logo-wrapper img {
    width: 100%;
    height: auto;
    display: block;
}

.navbar-nav .nav-link {
    position: relative;
    padding: 0.55rem 0;
    margin: 0 0.95rem;
    font-weight: 600;
    color: var(--color-text-secondary);
    transition: color var(--transition-base);
}

.navbar-nav .nav-link:hover,
.navbar-nav .nav-link:focus,
.navbar-nav .nav-link.active {
    color: var(--color-primary);
}

.navbar-nav .nav-link::after {
    content: "";
    position: absolute;
    left: 50%;
    bottom: -0.45rem;
    width: 0;
    height: 3px;
    border-radius: 999px;
    background: linear-gradient(90deg, var(--color-primary), var(--color-secondary));
    transition: width 180ms ease, left 180ms ease;
}

.navbar-nav .nav-link:hover::after,
.navbar-nav .nav-link:focus::after,
.navbar-nav .nav-link.active::after {
    width: 70%;
    left: 15%;
}


.app-main {
    flex: 1;
    width: min(1160px, 96vw);
    margin: 0 auto;
    padding: 2.75rem 0 2.75rem;
}

.app-main.wide {
    width: 100%;
    padding: clamp(1.5rem, 3vw, 2.75rem) 0 clamp(2.5rem, 4vw, 3.25rem);
}

.app-hero {
    width: min(1160px, 96vw);
    margin: 0 auto;
    padding-top: 4.25rem;
    padding-bottom: 2.5rem;
}

.hero-card {
    background: linear-gradient(135deg, var(--color-surface), var(--color-surface-soft));
    border-radius: var(--radius-lg);
    padding: clamp(2.4rem, 6vw, 4.2rem);
    border: 1px solid var(--color-border);
    box-shadow: var(--shadow-lg);
    position: relative;
    overflow: hidden;
}

.hero-card::after {
    content: "";
    position: absolute;
    inset: 0;
    pointer-events: none;
    background: radial-gradient(circle at 20% 20%, rgba(99, 146, 255, 0.35), transparent 55%), radial-gradient(circle at 80% 0%, rgba(96, 212, 255, 0.22), transparent 50%);
    opacity: 0.85;
}

.hero-body {
    position: relative;
    z-index: 2;
    display: grid;
    gap: 1.7rem;
    max-width: 680px;
}

/* Rank badges – ghost shield */
.rank-badge {
    width: 120px;
    height: 150px;
    display: inline-block;
    color: #5f7bff;
}

.rank-badge:hover .badge-shield,
.rank-badge:focus-visible .badge-shield {
    filter:
        drop-shadow(0 0 12px currentColor)
        drop-shadow(0 0 28px rgba(0, 0, 0, 0.55));
}

.badge-shield {
    width: 100%;
    height: 100%;
    display: block;
    position: relative;
    pointer-events: none;
    background: linear-gradient(180deg, #101829 0%, #070c18 100%);
    background-size: 100% 100%;
    transition: background 0.3s ease, filter 0.3s ease;
    filter:
        drop-shadow(0 0 6px currentColor)
        drop-shadow(0 0 12px rgba(0, 0, 0, 0.4));
}

.badge-shield::after {
    content: "";
    position: absolute;
    top: -60%;
    left: -120%;
    width: 200%;
    height: 220%;
    background: linear-gradient(120deg, rgba(255, 255, 255, 0.32) 0%, rgba(255, 255, 255, 0) 60%);
    transform: rotate(12deg) translateX(-140%);
    mix-blend-mode: screen;
    animation: badge-shield-shine 6s linear infinite;
}

.badge-shield-border {
    fill: none;
    stroke: currentColor;
    stroke-width: 4;
    stroke-linejoin: round;
    stroke-linecap: round;
    filter:
        drop-shadow(0 0 6px currentColor)
        drop-shadow(0 0 12px rgba(0, 0, 0, 0.4));
}

.badge-ghost-fill,
.badge-hood,
.badge-mask,
.badge-eyes {
    transform-box: fill-box;
    transform-origin: 50% 50%;
    animation: ghostFloat 3s ease-in-out infinite;
}

.badge-ghost-fill {
    fill: #00ffd5;
    opacity: 1;
    stroke: none;
}

.badge-hood {
    fill: none;
    stroke: #22f7c4;
    stroke-width: 3;
    stroke-linejoin: round;
    filter: drop-shadow(0 0 6px #22f7c4);
}

.badge-mask {
    fill: #020617;
    stroke: #22f7c4;
    stroke-width: 2;
}

.badge-eyes {
    fill: #22f7c4;
    stroke: none;
    animation: ghostFloat 3s ease-in-out infinite, ghostBlink 2.4s infinite steps(1, end);
}

.rank-badge .badge-rings,
.rank-badge .badge-crown {
    opacity: 0;
    transition: opacity 0.3s ease, color 0.3s ease, stroke 0.3s ease;
    color: rgba(94, 132, 255, 0.45);
    stroke: rgba(94, 132, 255, 0.45);
}

.rank--trainee {
    color: #00ff33;
}

/* Rank-specific ghost body colors */
.rank--trainee .badge-ghost-fill    { fill: #0dde68; }
.rank--junior .badge-ghost-fill     { fill: #003ffc; }
.rank--specialist .badge-ghost-fill { fill: #b54cff; }
.rank--senior .badge-ghost-fill     { fill: #ee2f2f; }
.rank--principal .badge-ghost-fill  { fill: #f3d779; }

.rank--senior {
    color: #ff4d4d;
}

.rank--senior .badge-rings {
    color: #ff4d4d;
    stroke: #ff4d4d;
}

.rank--principal {
    color: #ffca2a;
}

.rank--senior .badge-rings,
.rank--principal .badge-rings {
    opacity: 1;
}

.rank--principal .badge-rings,
.rank--principal .badge-crown {
    color: #ffca2a;
    stroke: #ffca2a;
}

.leaderboard-rank-badge {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0;
    margin: 0 auto;
}

.rank-badge--compact {
    display: block;
    width: auto;
    max-height: 32px;
    flex-shrink: 0;
    margin: 0;
}

.leaderboard-rank-name {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.3rem 0.8rem;
    border-radius: 999px;
    border: 1px solid rgba(124, 146, 255, 0.35);
    background: rgba(15, 23, 42, 0.85);
    font-size: 0.78rem;
    font-weight: 600;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: rgba(224, 231, 255, 0.9);
    gap: 0.25rem;
    min-width: 92px;
    justify-self: flex-start;
}

.leaderboard-rank-name.is-unranked {
    border-color: rgba(148, 163, 184, 0.4);
    background: rgba(30, 41, 59, 0.65);
    color: rgba(203, 213, 225, 0.9);
}

.leaderboard-rank-name.rank--trainee {
    border-color: rgba(52, 211, 153, 0.55);
    background: rgba(52, 211, 153, 0.14);
    color: #a7f3d0;
}

.leaderboard-rank-name.rank--junior {
    border-color: rgba(96, 165, 250, 0.55);
    background: rgba(96, 165, 250, 0.14);
    color: #bfdbfe;
}

.leaderboard-rank-name.rank--specialist {
    border-color: rgba(181, 76, 255, 0.55);
    background: rgba(181, 76, 255, 0.16);
    color: #e9d5ff;
}

.leaderboard-rank-name.rank--senior {
    border-color: rgba(255, 77, 77, 0.55);
    background: rgba(255, 77, 77, 0.14);
    color: #fecdd3;
}

.leaderboard-rank-name.rank--principal {
    border-color: rgba(255, 202, 42, 0.55);
    background: rgba(255, 202, 42, 0.16);
    color: #fef3c7;
}

.leaderboard-rank-badge svg {
    display: block;
    margin: 0;
}

.rank--principal .badge-crown {
    opacity: 1;
}

@keyframes badge-shield-shine {
    0% {
        transform: rotate(12deg) translateX(-140%);
        opacity: 0;
    }

    12% {
        transform: rotate(12deg) translateX(60%);
        opacity: 1;
    }

    25% {
        transform: rotate(12deg) translateX(160%);
        opacity: 0;
    }

    100% {
        transform: rotate(12deg) translateX(160%);
        opacity: 0;
    }
}

@keyframes ghostFloat {
    0% {
        transform: translateY(0);
    }

    50% {
        transform: translateY(-4px);
    }

    100% {
        transform: translateY(0);
    }
}

@keyframes ghostBlink {
    0%, 88%, 100% {
        opacity: 1;
    }

    90%, 96% {
        opacity: 0;
    }
}

@media (prefers-reduced-motion: reduce) {
    .badge-shield,
    .badge-shield::after,
    .badge-hood,
    .badge-mask,
    .badge-eyes {
        animation: none !important;
        transition: none !important;
    }
}

.hero-eyebrow {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: rgba(255, 255, 255, 0.08);
    border: 1px solid var(--color-border);
    border-radius: 999px;
    padding: 0.35rem 0.9rem;
    font-size: 0.8rem;
    font-weight: 600;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--color-text-secondary);
}

.hero-card p {
    color: var(--color-text);
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.45rem;
    border-radius: 999px;
    font-weight: 600;
    letter-spacing: 0.01em;
    padding: 0.65rem 1.35rem;
    border: none;
    cursor: pointer;
    transition: transform var(--transition-base), box-shadow var(--transition-base), background var(--transition-base), color var(--transition-base);
}

.btn:focus {
    outline: none;
    box-shadow: 0 0 0 0.2rem rgba(72, 101, 255, 0.25);
}

.btn-primary {
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-strong));
    color: var(--color-on-primary);
    box-shadow: 0 18px 35px rgba(72, 101, 255, 0.28);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 24px 45px rgba(72, 101, 255, 0.38);
}

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

.btn-outline-primary:hover {
    background: var(--color-primary);
    color: var(--color-on-primary);
    box-shadow: 0 18px 35px rgba(72, 101, 255, 0.28);
}

.btn-success {
    background: linear-gradient(135deg, var(--color-success), #00a773);
    color: var(--color-on-success);
    box-shadow: 0 18px 35px rgba(0, 179, 118, 0.32);
}

.btn-warning {
    background: linear-gradient(135deg, var(--color-warning), #ff9535);
    color: var(--color-on-warning);
    box-shadow: 0 18px 35px rgba(255, 171, 77, 0.32);
}

.btn-danger {
    background: linear-gradient(135deg, var(--color-danger), #ff3e59);
    color: var(--color-on-danger);
    box-shadow: 0 18px 35px rgba(255, 94, 115, 0.32);
}

.btn-light {
    background: var(--color-surface);
    color: var(--color-text);
    border: 1px solid var(--color-border);
}

.btn-light:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-sm);
}

.lesson-page {
    width: min(1440px, 95vw);
    margin: 0 auto;
    padding-inline: clamp(1rem, 4vw, 3rem);
}

.lesson-heading h1 {
    font-size: clamp(2rem, 3.2vw, 3.25rem);
}

.lesson-video-section {
    display: grid;
    gap: 1.5rem;
}

.lesson-video-wrapper {
    position: relative;
    background: #04070f;
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border-strong);
    box-shadow: var(--shadow-md);
    overflow: hidden;
    aspect-ratio: 16 / 9;
    max-height: 72vh;
    min-height: clamp(420px, 60vh, 760px);
}

.lesson-video-embed {
    width: 100%;
    height: 100%;
    border: 0;
    display: block;
    background: #000;
}

.lesson-body {
    display: grid;
    gap: 1.25rem;
}

.lesson-content {
    background: linear-gradient(145deg, var(--color-surface), var(--color-surface-soft));
    border-radius: var(--radius-md);
    border: 1px solid var(--color-border);
    padding: clamp(1.5rem, 2.5vw, 2.25rem);
    box-shadow: var(--shadow-sm);
}

.lesson-content.rich-text > *:last-child {
    margin-bottom: 0;
}

.lesson-sidebar {
    position: sticky;
    top: 6.5rem;
}

.lesson-list .list-group-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.75rem;
    padding: 0.9rem 1.15rem;
    font-weight: 600;
}

.lesson-list .list-group-item .badge {
    margin-left: auto;
}

.lesson-list .list-group-item.active {
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
    color: var(--color-on-primary);
    border-color: transparent;
}

.lesson-list .list-group-item.active .badge {
    background: rgba(255, 255, 255, 0.18);
}

.lesson-list-title {
    flex: 1 1 auto;
}

@media (max-width: 1199.98px) {
    .lesson-page {
        width: min(1200px, 96vw);
        padding-inline: clamp(1rem, 5vw, 2rem);
    }

    .lesson-sidebar {
        position: static;
    }

    .lesson-video-wrapper {
        min-height: clamp(360px, 58vw, 640px);
        max-height: none;
    }
}

@media (max-width: 767.98px) {
    .lesson-page {
        padding-inline: 1rem;
    }

    .lesson-video-wrapper {
        min-height: clamp(260px, 58vw, 420px);
    }

    .lesson-list .list-group-item {
        padding: 0.85rem 1rem;
    }
}

.card {
    border-radius: var(--radius-md);
    border: 1px solid var(--color-border);
    background: linear-gradient(145deg, var(--color-surface), var(--color-surface-soft));
    box-shadow: var(--shadow-sm);
    transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

.card-header, .card-footer {
    border: none;
    background: transparent;
}

.card-body {
    padding: 1.5rem;
}

.section-heading {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    margin-bottom: 1.4rem;
}

.section-actions {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.section-actions .btn {
    white-space: nowrap;
}

.section-heading + .section-heading {
    margin-top: 3.6rem;
}

.section-heading p {
    margin: 0;
}

.badge {
    display: inline-flex;
    align-items: center;
    padding: 0.3rem 0.7rem;
    border-radius: 999px;
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    background: var(--color-surface-accent);
    color: var(--color-text);
    border: 1px solid var(--color-border);
}

.badge-level {
    background: rgba(120, 138, 255, 0.18);
    border-color: rgba(120, 138, 255, 0.38);
    color: rgba(222, 227, 255, 0.92);
}

.badge-level-beginner {
    background: rgba(52, 211, 153, 0.2);
    border-color: rgba(52, 211, 153, 0.45);
    color: rgba(223, 255, 241, 0.94);
}

.badge-level-intermediate {
    background: rgba(74, 158, 255, 0.21);
    border-color: rgba(74, 158, 255, 0.48);
    color: rgba(223, 238, 255, 0.94);
}

.badge-level-advanced {
    background: rgba(171, 123, 255, 0.22);
    border-color: rgba(171, 123, 255, 0.46);
    color: rgba(243, 232, 255, 0.95);
}

.badge-level-expert {
    background: rgba(255, 149, 82, 0.22);
    border-color: rgba(255, 149, 82, 0.48);
    color: rgba(255, 239, 225, 0.94);
}

.badge-level-default {
    background: rgba(124, 144, 255, 0.18);
    border-color: rgba(124, 144, 255, 0.38);
    color: rgba(225, 231, 255, 0.92);
}

.badge-free {
    background: rgba(0, 195, 138, 0.18);
    border-color: rgba(0, 195, 138, 0.35);
    color: var(--color-success);
}

.badge-paid {
    background: rgba(255, 156, 69, 0.2);
    border-color: rgba(255, 156, 69, 0.38);
    color: var(--color-warning);
}

.table {
    border-collapse: separate;
    border-spacing: 0;
    width: 100%;
    background: var(--color-surface);
    border-radius: var(--radius-md);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}

.table thead {
    background: var(--color-surface-accent);
    text-transform: uppercase;
    letter-spacing: 0.06em;
    font-size: 0.75rem;
}

.table th, .table td {
    padding: 1rem 1.15rem;
    border-bottom: 1px solid var(--color-border);
    color: var(--color-text);
}

.table tbody tr:hover {
    background: rgba(84, 113, 255, 0.08);
}

.form-control, .form-select {
    border-radius: var(--radius-sm);
    border: 1px solid var(--color-border);
    background: var(--color-surface);
    color: var(--color-text);
    padding: 0.65rem 0.9rem;
    font-weight: 500;
    transition: box-shadow var(--transition-base), border-color var(--transition-base), background var(--transition-base);
}

.form-control:focus, .form-select:focus {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 0.2rem var(--color-primary-soft);
    background: var(--color-surface);
}

input::placeholder, textarea::placeholder {
    color: var(--color-text-secondary);
}

.alert {
    border-radius: var(--radius-md);
    border: 1px solid var(--color-border-strong);
    background: var(--color-surface-soft);
    color: var(--color-text);
    box-shadow: var(--shadow-sm);
}

.alert-info {
    border-color: rgba(76, 183, 255, 0.35);
    background: rgba(76, 183, 255, 0.12);
}

.alert-danger {
    border-color: rgba(255, 94, 115, 0.45);
    background: rgba(255, 94, 115, 0.12);
}

.alert-success {
    border-color: rgba(0, 195, 138, 0.35);
    background: rgba(0, 195, 138, 0.12);
}

.app-footer {
    margin-top: auto;
    padding: 2.5rem 0 3rem;
    background: linear-gradient(160deg, rgba(11, 18, 34, 0.92), rgba(8, 14, 26, 0.88));
    border-top: 1px solid rgba(255, 255, 255, 0.05);
}

.footer-inner {
    width: min(1160px, 96vw);
    margin: 0 auto;
    display: grid;
    gap: 1.2rem;
    color: var(--color-text-secondary);
}

.footer-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 1.5rem;
    align-items: center;
    justify-content: space-between;
}

.app-footer .footer-meta .d-flex {
    display: none;
}

.footer-inner strong {
    color: var(--color-text);
}

.footer-meta a {
    color: var(--color-text-secondary);
}

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

.app-footer .stats-grid {
    display: none;
}

.stat-card {
    background: var(--color-surface-soft);
    border-radius: var(--radius-md);
    padding: 1.15rem 1.2rem;
    border: 1px solid var(--color-border);
    box-shadow: var(--shadow-sm);
}

.stat-card strong {
    display: block;
    font-size: 1.45rem;
    color: var(--color-primary);
}

.course-grid {
    display: grid;
    gap: 1.6rem;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

.new-courses-grid .course-card.is-collapsed {
    display: none;
}

.new-courses-grid {
    margin-bottom: 3rem;
}

.new-courses-toggle {
    white-space: nowrap;
}

.course-card .card-body {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.course-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 0.6rem;
}

.course-stats {
    display: flex;
    gap: 1rem;
    font-size: 0.85rem;
    color: var(--color-text-secondary);
}

.auth-shell {
    width: min(480px, 100%);
    margin: 3rem auto 0;
}

.auth-card {
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
    background: linear-gradient(155deg, var(--color-surface), var(--color-surface-soft));
    padding: clamp(2rem, 5vw, 2.75rem);
    box-shadow: var(--shadow-md);
}

.auth-header {
    margin-bottom: 1.8rem;
}

.auth-header h2 {
    margin-bottom: 0.35rem;
}

.auth-footer {
    margin-top: 2rem;
    text-align: center;
    color: var(--color-text-secondary);
}

.form-grid {
    display: grid;
    gap: 1.15rem;
}

.form-grid .form-label {
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: 0.45rem;
}

.table-responsive {
    border-radius: var(--radius-md);
    border: 1px solid var(--color-border);
    box-shadow: var(--shadow-sm);
    background: var(--color-surface);
}

.fade-in {
    animation: fadeInUp 420ms ease forwards;
    opacity: 0;
    transform: translateY(12px);
}

@keyframes fadeInUp {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* --- Admin workspace styling --- */
.admin-surface {
    margin: 0;
    padding: 0 0 clamp(2.75rem, 4vw, 4rem);
    background: none;
    color: var(--color-text);
}

.admin-shell {
    width: min(1160px, 96vw);
    margin: 0 auto;
    display: grid;
    gap: clamp(2rem, 3vw, 2.75rem);
}

.admin-header {
    border-radius: var(--radius-lg);
    padding: clamp(2rem, 3vw, 2.75rem);
    display: grid;
    gap: clamp(0.75rem, 2vw, 1.25rem);
    background: linear-gradient(155deg, var(--color-surface), var(--color-surface-soft));
    border: 1px solid var(--color-border);
    box-shadow: var(--shadow-md);
}

.admin-header-title {
    display: grid;
    gap: 0.75rem;
    max-width: 640px;
}

.admin-header-title h1,
.admin-header-title h2,
.admin-header-title h3 {
    margin: 0;
    letter-spacing: -0.015em;
}

.admin-header-title p {
    margin: 0;
    color: var(--color-text-secondary);
}

.admin-primary-btn {
    border-radius: 999px;
    padding: 0.75rem 1.6rem;
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
    color: var(--color-on-primary);
    font-weight: 600;
    border: none;
    box-shadow: var(--shadow-md);
    transition: transform 180ms ease, box-shadow 180ms ease;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

.admin-primary-btn:hover,
.admin-primary-btn:focus {
    transform: translateY(-2px);
    color: var(--color-on-primary);
    box-shadow: var(--shadow-lg);
}

.admin-stat-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: clamp(1.1rem, 2vw, 1.6rem);
}

.admin-stat-card {
    border-radius: var(--radius-lg);
    padding: clamp(1.5rem, 2.1vw, 1.9rem);
    border: 1px solid var(--color-border);
    background: linear-gradient(155deg, var(--color-surface), var(--color-surface-soft));
    box-shadow: var(--shadow-sm);
    display: grid;
    gap: 0.6rem;
}

.admin-stat-card span {
    font-size: 0.82rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--color-text-secondary);
}

.admin-stat-card strong {
    font-size: clamp(1.9rem, 3vw, 2.3rem);
    color: var(--color-primary);
    font-weight: 700;
}

.admin-card,
.admin-surface .card {
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
    background: linear-gradient(150deg, var(--color-surface), var(--color-surface-soft));
    box-shadow: var(--shadow-md);
    color: var(--color-text);
}

.admin-surface .card-header {
    border-bottom: 1px solid var(--color-border);
    background: rgba(255, 255, 255, 0.02);
    color: var(--color-text-secondary);
    font-weight: 600;
}

.admin-surface .card-body {
    color: var(--color-text-secondary);
}

.course-logo-admin-preview {
    width: 120px;
    height: 120px;
    border-radius: 24px;
    border: 1px dashed rgba(123, 140, 255, 0.32);
    background: rgba(18, 26, 54, 0.6);
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    position: relative;
    transition: border-color 180ms ease, background 180ms ease;
}

.course-logo-admin-preview img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: inherit;
}

.course-logo-admin-preview .logo-placeholder {
    font-size: 0.85rem;
    color: rgba(204, 212, 255, 0.7);
    text-align: center;
    padding: 0 0.75rem;
}

.admin-table {
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
    background: linear-gradient(150deg, var(--color-surface), var(--color-surface-soft));
    box-shadow: var(--shadow-md);
    overflow: visible;
    padding: clamp(0.35rem, 1vw, 0.6rem);
}

.admin-table table {
    width: 100%;
    margin: 0;
    border-collapse: separate;
    border-spacing: 0;
    color: var(--color-text);
    border-radius: calc(var(--radius-lg) - clamp(0.35rem, 1vw, 0.6rem));
    overflow: hidden;
}

.admin-table thead {
    background: rgba(255, 255, 255, 0.04);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    font-size: 0.72rem;
    color: var(--color-text-secondary);
}

.admin-table th,
.admin-table td {
    padding: 0.95rem 1.15rem;
    border-bottom: 1px solid var(--color-border);
    vertical-align: middle;
}

.admin-table tbody tr:hover {
    background: rgba(255, 255, 255, 0.03);
}

.admin-table tbody tr:last-child td {
    border-bottom: none;
}

.admin-table .badge {
    border-radius: 999px;
    padding: 0.3rem 0.75rem;
    font-weight: 600;
    letter-spacing: 0.05em;
}

.admin-table-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.admin-table-actions form {
    display: inline-flex;
}

.admin-pill,
.admin-list a .admin-pill {
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    padding: 0.35rem 0.85rem;
    border-radius: 999px;
    background: rgba(127, 155, 255, 0.18);
    border: 1px solid rgba(127, 155, 255, 0.35);
    font-size: 0.75rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: rgba(233, 238, 255, 0.9);
}

.admin-list {
    display: grid;
    gap: clamp(1rem, 2vw, 1.4rem);
}

.admin-list a {
    display: grid;
    gap: 0.5rem;
    padding: 1.35rem 1.5rem;
    border-radius: var(--radius-lg);
    background: rgba(255, 255, 255, 0.02);
    border: 1px solid var(--color-border);
    color: var(--color-text);
    box-shadow: var(--shadow-sm);
    transition: transform 180ms ease, border-color 180ms ease, box-shadow 180ms ease, color 180ms ease;
}

.admin-list a:hover,
.admin-list a:focus {
    transform: translateY(-3px);
    border-color: rgba(127, 155, 255, 0.45);
    box-shadow: var(--shadow-md);
    color: var(--color-primary);
}

.admin-list a h5 {
    margin: 0;
    font-size: 1.05rem;
    font-weight: 600;
}

.admin-list a small {
    color: var(--color-text-secondary);
}

.admin-alert,
.admin-surface .alert {
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
    background: rgba(255, 255, 255, 0.02);
    color: var(--color-text-secondary);
    box-shadow: var(--shadow-sm);
}

.admin-back-link {
    display: inline-flex;
    align-items: center;
    gap: 0.45rem;
    font-size: 0.82rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--color-text-secondary);
    transition: color 160ms ease;
}

.admin-back-link:hover {
    color: var(--color-primary);
}

.admin-form-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 0.8rem;
}

.admin-surface .form-control,
.admin-surface .form-select {
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--color-border);
    color: var(--color-text);
}

.admin-surface .form-control:focus,
.admin-surface .form-select:focus {
    border-color: rgba(127, 155, 255, 0.55);
    box-shadow: 0 0 0 0.2rem rgba(127, 155, 255, 0.25);
    background: rgba(255, 255, 255, 0.06);
}

.admin-surface .form-label {
    color: var(--color-text-secondary);
    font-weight: 600;
}

.admin-surface .form-check-label {
    color: var(--color-text-secondary);
}

.admin-surface hr {
    border-color: var(--color-border);
}

.admin-table .text-muted {
    color: var(--color-text-secondary) !important;
}

.admin-table .btn,
.admin-table-actions .btn {
    border-radius: 999px;
}

.admin-search-form {
    display: flex;
    flex-wrap: wrap;
    gap: 0.6rem;
}

@media (max-width: 767.98px) {
    .admin-shell {
        gap: 1.8rem;
    }

    .admin-header {
        padding: 1.75rem;
    }

    .admin-card .card-body {
        padding: 1.75rem;
    }

    .admin-primary-btn {
        width: 100%;
        justify-content: center;
    }

    .admin-table {
        border-radius: 20px;
    }
}
@media (max-width: 992px) {
    .navbar-nav .nav-link {
        margin: 0.4rem 0;
    }

    .app-main, .app-hero {
        width: min(96vw, 960px);
        padding-left: 0;
        padding-right: 0;
    }

    .hero-actions {
        flex-direction: column;
        align-items: flex-start;
    }

}

@media (max-width: 768px) {
    .app-main {
        padding-top: 2.75rem;
    }

    .app-header .navbar {
        padding: 0.75rem 0;
    }

    .hero-card {
        padding: 2rem;
    }

    .auth-card {
        padding: 1.8rem;
    }
}