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

html {
    scrollbar-gutter: stable;
    font-family: 'Inter', 'Segoe UI', system-ui, sans-serif !important;
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

:root {
    --primary-color: #1976d2;
    --secondary-color: #388e3c;
    --danger-color: #d32f2f;
    --warning-color: #f57c00;
    --light-bg: #f5f5f5;
    --border-color: #ddd;
    --text-color: #333;
    --text-light: #666;
    --font-primary: 'Inter', 'Segoe UI', system-ui, sans-serif;
    --text-xs: 0.75rem;
    --text-sm: 0.875rem;
    --text-base: 1rem;
    --text-lg: 1.125rem;
    --text-xl: 1.25rem;
    --text-2xl: clamp(1.375rem, 1.15rem + 0.75vw, 1.75rem);
    --text-3xl: clamp(1.75rem, 1.35rem + 1.25vw, 2.25rem);
}

body {
    display: grid;
    grid-template-rows: auto 1fr auto;
    min-height: 100vh;
    overflow-x: hidden;
    scroll-behavior: smooth;
    font-family: var(--font-primary) !important;
    font-size: var(--text-base);
    line-height: 1.625;
    letter-spacing: -0.006em;
    color: var(--text-color);
    background-color: var(--light-bg);
}

button,
input,
select,
textarea {
    font: inherit;
    letter-spacing: inherit;
}

h1,
h2,
h3,
h4,
h5,
h6 {
    line-height: 1.25;
    letter-spacing: -0.025em;
    text-wrap: balance;
}

p,
li,
td,
th,
label {
    line-height: 1.55;
}

small,
.text-sm {
    line-height: 1.45;
}

@media (max-width: 639px) {
    html {
        font-size: 15px;
    }
}

body > main {
    transform-origin: 50% 0;
    animation: app-page-enter 0.68s cubic-bezier(0.16, 1, 0.3, 1) both;
}

@keyframes app-page-enter {
    from {
        opacity: 0;
        filter: blur(9px);
        transform: translateY(24px) scale(0.985);
        clip-path: inset(0 0 14% 0 round 18px);
    }
    to {
        opacity: 1;
        filter: blur(0);
        transform: translateY(0);
        clip-path: inset(0 0 0 0 round 0);
    }
}

body > main > * {
    animation: app-content-enter 0.52s cubic-bezier(0.22, 1, 0.36, 1) both;
}

body > main > *:nth-child(3n + 1) { animation-delay: 0.12s; }
body > main > *:nth-child(3n + 2) { animation-delay: 0.2s; }
body > main > *:nth-child(3n) { animation-delay: 0.28s; }

/* Dialogs are initially hidden and must never inherit the page-entry opacity. */
body > main > .modal-overlay,
body > main > .modal {
    animation: none !important;
    opacity: 1;
    transform: none;
}

/* Modal luôn neo theo viewport; chỉ phần thân modal được phép cuộn. */
body:has(.modal-overlay[style*="display: flex"]),
body:has(.custom-modal[style*="display: flex"]),
body:has(.ui-modal-backdrop),
body:has(.course-attempt-dialog[open]),
body:has(.course-modal-backdrop[style*="display: block"]),
body:has(.grade-change-modal-backdrop[style*="display: block"]) {
    overflow: hidden;
}

@keyframes app-content-enter {
    from {
        opacity: 0;
        transform: translateY(18px) scale(0.98);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

@media (prefers-reduced-motion: reduce) {
    body > main,
    body > main > * {
        animation: none;
    }
}

.app-navbar {
    position: sticky;
    top: 0;
    z-index: 1200;
    border-bottom: 1px solid #e5e7eb;
    background: rgba(255, 255, 255, 0.92);
    backdrop-filter: blur(16px);
    box-shadow: 0 10px 30px rgba(15, 23, 42, 0.06);
}

.app-navbar__inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 18px;
    width: min(1280px, calc(100% - 32px));
    min-height: 72px;
    margin: 0 auto;
}

.app-navbar__brand {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    color: #111827;
    text-decoration: none;
}

.app-navbar__brand img {
    width: 38px;
    height: 38px;
    object-fit: contain;
}

.app-navbar__brand-copy {
    display: grid;
    gap: 2px;
    line-height: 1.15;
}

.app-navbar__brand-copy strong {
    color: #0f172a;
    font-size: 1rem;
    font-weight: 700;
    letter-spacing: -0.015em;
}

.app-navbar__brand-copy small {
    color: #475569;
    font-size: 0.78rem;
    font-weight: 500;
    white-space: nowrap;
}

.app-navbar__links {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 6px;
    border: 1px solid #e5e7eb;
    border-radius: 999px;
    background: #f8fafc;
}

.app-navbar__links a {
    min-height: 40px;
    padding: 0 14px;
    border-radius: 999px;
    color: #475569;
    font-size: 0.95rem;
    font-weight: 700;
    line-height: 40px;
    text-decoration: none;
    transition: background-color 0.18s ease, color 0.18s ease, box-shadow 0.18s ease;
}

.app-navbar__links a:hover,
.app-navbar__links a.is-active {
    background: #ffffff;
    color: #2563eb;
    box-shadow: 0 8px 18px rgba(15, 23, 42, 0.08);
}

.app-navbar__account {
    display: inline-flex;
    align-items: center;
    margin-left: auto;
}

.app-navbar__user-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 4px 12px 4px 4px;
    border: 1px solid transparent;
    border-radius: 999px;
    background: transparent;
    cursor: pointer;
    transition: background-color 0.18s ease, border-color 0.18s ease;
}

.app-navbar__user-btn:hover {
    background: #f1f5f9;
    border-color: #e2e8f0;
}

.app-navbar__user {
    color: #334155;
    font-size: 0.92rem;
    font-weight: 700;
    white-space: nowrap;
}

.ui-dropdown__menu--right {
    right: 0;
    left: auto;
}

.app-navbar__ghost,
.app-navbar__danger {
    min-height: 40px;
    padding: 0 13px;
    border: 1px solid #e5e7eb;
    border-radius: 999px;
    background: #ffffff;
    color: #111827;
    font-size: 0.9rem;
    font-weight: 800;
    cursor: pointer;
    transition: transform 0.18s ease, box-shadow 0.18s ease, border-color 0.18s ease;
}

.app-navbar__ghost:hover,
.app-navbar__danger:hover {
    transform: translateY(-1px);
    box-shadow: 0 10px 20px rgba(15, 23, 42, 0.1);
}

.app-navbar__danger {
    border-color: #fecaca;
    color: #dc2626;
}

.account-dialog {
    width: min(560px, calc(100vw - 28px));
    padding: 0;
    border: 0;
    border-radius: 18px;
    background: transparent;
}

.account-dialog::backdrop {
    background: rgba(15, 23, 42, 0.42);
    backdrop-filter: blur(5px);
}

.account-dialog__panel {
    overflow: hidden;
    border: 1px solid #e5e7eb;
    border-radius: 18px;
    background: #ffffff;
    box-shadow: 0 26px 70px rgba(15, 23, 42, 0.24);
}

.account-dialog__header,
.account-dialog__footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    padding: 20px 22px;
}

.account-dialog__header {
    border-bottom: 1px solid #e5e7eb;
}

.account-dialog__header h2 {
    margin-top: 10px;
    color: #111827;
    font-size: 1.55rem;
    font-weight: 800;
}

.account-dialog__close {
    width: 36px;
    height: 36px;
    border: 0;
    border-radius: 999px;
    background: #f1f5f9;
    color: #64748b;
    font-size: 1.5rem;
    line-height: 1;
    cursor: pointer;
}

.account-dialog__body {
    display: grid;
    gap: 14px;
    padding: 22px;
}

.account-dialog__body label {
    display: grid;
    gap: 7px;
    margin: 0;
}

.account-dialog__body span {
    color: #111827;
    font-size: 0.92rem;
    font-weight: 800;
}

.account-dialog__body input {
    width: 100%;
    min-height: 48px;
    border: 1px solid #d1d5db;
    border-radius: 12px;
    padding: 0 14px;
    background: #ffffff;
    color: #111827;
}

.account-dialog__body input:disabled {
    background: #f8fafc;
    color: #64748b;
}

.account-dialog__body input:focus {
    border-color: #2563eb;
    outline: 3px solid rgba(37, 99, 235, 0.14);
}

.account-dialog__divider {
    height: 1px;
    margin: 4px 0;
    background: #e5e7eb;
}

.account-dialog__footer {
    justify-content: flex-end;
    border-top: 1px solid #e5e7eb;
    background: #f8fafc;
}

.account-page {
    display: grid;
    gap: 1rem;
    padding-top: 0.5rem;
}

.account-page__hero {
    display: grid;
    gap: 0.25rem;
}

.account-page__hero h1 {
    margin: 0;
    color: #0f172a;
    font-size: clamp(1.7rem, 3vw, 2.35rem);
    font-weight: 900;
    letter-spacing: 0;
}

.account-page__hero p {
    margin: 0;
    max-width: 42rem;
    color: #64748b;
    font-size: 0.95rem;
}

.account-page__grid {
    display: grid;
    grid-template-columns: minmax(220px, 0.55fr) minmax(0, 1.45fr);
    gap: 1rem;
    align-items: start;
}

.account-page__summary,
.account-page__form {
    border: 1px solid #e2e8f0;
    border-radius: 1rem;
    background: #ffffff;
    box-shadow: 0 24px 70px rgba(15, 23, 42, 0.08);
}

.account-page__summary {
    display: grid;
    gap: 0.75rem;
    padding: 1rem;
}

.account-page__summary h2 {
    margin: 0;
    color: #0f172a;
    font-size: 1.1rem;
    font-weight: 800;
}

.account-page__summary p {
    margin: 0.1rem 0 0;
    color: #64748b;
    font-size: 0.92rem;
    font-weight: 600;
}

.account-page__summary dl {
    display: grid;
    gap: 0.5rem;
    margin: 0;
    padding-top: 0.25rem;
}

.account-page__summary dt {
    color: #64748b;
    font-size: 0.8rem;
    font-weight: 700;
}

.account-page__summary dd {
    margin: 0.1rem 0 0;
    color: #0f172a;
    font-size: 0.96rem;
    font-weight: 800;
}

.account-page__form {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1rem;
    padding: 1rem;
}

.account-page__section {
    display: grid;
    align-content: start;
    gap: 0.75rem;
}

.account-page__section h2 {
    margin: 0;
    color: #0f172a;
    font-size: 1.05rem;
    font-weight: 850;
}

.account-page__section p {
    margin: -0.25rem 0 0;
    color: #64748b;
    font-size: 0.86rem;
}

.account-page__field {
    display: grid;
    gap: 0.32rem;
}

.account-page__field span {
    color: #0f172a;
    font-size: 0.88rem;
    font-weight: 800;
}

.account-page__field input {
    width: 100%;
    border: 1px solid #cbd5e1;
    border-radius: 0.72rem;
    background: #ffffff;
    padding: 0.72rem 0.85rem;
    color: #0f172a;
    font-size: 0.92rem;
    font-weight: 600;
    transition: border-color 0.18s ease, box-shadow 0.18s ease;
}

.account-page__field input:disabled {
    background: #f8fafc;
    color: #64748b;
}

.account-page__field input:focus {
    outline: none;
    border-color: #2563eb;
    box-shadow: 0 0 0 4px rgba(37, 99, 235, 0.13);
}

.account-page__divider {
    display: none;
    height: 1px;
    background: #e2e8f0;
}

.account-page__actions {
    grid-column: 1 / -1;
    display: flex;
    justify-content: flex-end;
    gap: 0.65rem;
    padding-top: 0.15rem;
}

@media (max-width: 900px) {
    .account-page__grid,
    .account-page__form {
        grid-template-columns: 1fr;
    }

    .account-page__divider {
        display: block;
    }
}

@media (max-width: 980px) {
    .app-navbar__inner {
        align-items: stretch;
        flex-direction: column;
        min-height: 0;
        padding: 10px 16px;
        gap: 12px;
        width: 100%;
    }

    .app-navbar__account {
        display: flex !important;
        width: 100%;
        justify-content: center;
        visibility: visible;
        opacity: 1;
        margin-left: 0;
    }

    .app-navbar__user-btn {
        display: inline-flex !important;
        min-height: 48px;
        visibility: visible;
        opacity: 1;
    }

    .app-navbar__brand-copy small {
        display: block;
        white-space: normal;
    }

    .app-navbar__brand-copy strong {
        font-size: 0.95rem;
    }
}

@media (max-width: 760px) {
    .app-navbar__inner {
        padding: 10px 12px;
        gap: 8px;
    }

    .app-navbar__brand {
        min-width: 0;
        width: 100%;
    }

    .app-navbar__brand img {
        width: 32px;
        height: 32px;
        flex-shrink: 0;
    }

    .app-navbar__brand-copy {
        min-width: 0;
    }

    .app-navbar__brand-copy strong {
        font-size: 0.85rem;
        white-space: nowrap;
        overflow: hidden;
        text-overflow: ellipsis;
        display: block;
    }

    .app-navbar__brand-copy small {
        font-size: 0.72rem;
        line-height: 1.25;
    }

    .app-navbar__account {
        flex-shrink: 0;
    }

    .app-navbar__user-btn {
        padding: 4px 8px 4px 4px;
    }

    .app-navbar__user {
        max-width: min(260px, calc(100vw - 132px));
        overflow: hidden;
        text-overflow: ellipsis;
        white-space: nowrap;
        font-size: 0.85rem;
    }

    body > main {
        width: 100%;
        max-width: 100%;
        padding-left: 0.75rem !important;
        padding-right: 0.75rem !important;
    }
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Navigation */
.navbar {
    background-color: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    color: #0d47a1;
    padding: 0.8rem 0;
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.02);
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    width: 100%;
    z-index: 1000;
    transition: all 0.3s ease;
}

/* Modern Glassmorphism effect when scrolled */
.navbar.scrolled {
    padding: 0.7rem 0;
    background-color: rgba(255, 255, 255, 0.95);
    border-bottom: 1px solid rgba(0, 0, 0, 0.07);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.05);
}

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

.brand {
    font-size: 1.5rem;
    font-weight: bold;
}

.brand-logo {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    color: #0d47a1;
    text-decoration: none;
    line-height: 1;
    transition: transform 0.2s ease;
}

.brand-logo:hover {
    transform: scale(1.02);
}

.brand-logo-img {
    height: 45px;
    width: auto;
    display: block;
    object-fit: contain;
}

.brand-text {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-links a {
    color: #475569; /* slate-600 */
    font-weight: 600;
    text-decoration: none;
    transition: color 0.25s ease;
    position: relative;
    padding-bottom: 6px;
    font-size: 0.95rem;
}

.nav-links a::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: 0;
    left: 0;
    background-color: #0284c7;
    transition: width 0.3s cubic-bezier(0.165, 0.84, 0.44, 1);
    border-radius: 2px;
}

.nav-links a:hover::after,
.nav-links a.active::after {
    width: 100%;
}

.nav-links a:hover,
.nav-links a.active {
    color: #0284c7;
}

/* Main Content */
main.container {
    margin: 100px auto 2rem; /* offset for fixed navbar */
    width: 100%;
    min-height: 500px; /* Đảm bảo luôn có chiều cao tối thiểu để giữ form */
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 4px;
    font-size: 1rem;
    cursor: pointer;
    transition: background-color 0.3s;
    text-decoration: none;
}

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

.btn-primary:hover {
    background-color: #1565c0;
}

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

.btn-secondary:hover {
    background-color: #2e7d32;
}

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

.btn-danger:hover {
    background-color: #b71c1c;
}

/* Forms */
.form-group {
    margin-bottom: 1.5rem;
}

label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
}

input[type="text"],
input[type="number"],
select,
textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 1rem;
    font-family: inherit;
}

input[type="text"]:focus,
input[type="number"]:focus,
select:focus,
textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 4px rgba(25, 118, 210, 0.2);
}

.input-group {
    display: flex;
    align-items: stretch;
    width: 100%;
}

.input-group-addon {
    background-color: #e2e8f0;
    color: #475569;
    padding: 0 1rem;
    border: 1px solid var(--border-color);
    border-right: none;
    border-top-left-radius: 4px;
    border-bottom-left-radius: 4px;
    font-weight: bold;
    user-select: none;
    display: flex;
    align-items: center;
    justify-content: center;
}

.input-group input {
    border-top-left-radius: 0 !important;
    border-bottom-left-radius: 0 !important;
    flex: 1;
}

/* Tables */
table {
    width: 100%;
    border-collapse: collapse;
    margin: 1rem 0;
    background-color: white;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

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

th {
    background-color: var(--light-bg);
    font-weight: 600;
    color: var(--text-color);
}

tr:hover {
    background-color: #f9f9f9;
}

th:last-child,
td:last-child {
    text-align: right;
}

/* Alerts */
.alert {
    padding: 1rem;
    margin-bottom: 1rem;
    border-radius: 4px;
    border-left: 4px solid;
}

.alert-info {
    background-color: #e3f2fd;
    border-color: var(--primary-color);
    color: #0d47a1;
}

.alert-success {
    background-color: #e8f5e9;
    border-color: var(--secondary-color);
    color: #1b5e20;
}

.alert-warning {
    background-color: #fff3e0;
    border-color: var(--warning-color);
    color: #e65100;
}

.alert-danger {
    background-color: #ffebee;
    border-color: var(--danger-color);
    color: #b71c1c;
}

.toast-container {
    position: fixed;
    top: 1.25rem;
    right: 1.25rem;
    z-index: 2000;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    width: min(360px, calc(100vw - 2rem));
}

.toast {
    position: relative;
    overflow: hidden;
    background-color: white;
    border-radius: 10px;
    box-shadow: 0 14px 32px rgba(0, 0, 0, 0.16);
    border-left: 4px solid var(--primary-color);
    padding: 0.95rem 1rem 1.05rem;
    animation: toast-slide-in 0.25s ease-out;
}

.toast.toast-success {
    border-left-color: var(--secondary-color);
}

.toast.toast-error {
    border-left-color: var(--danger-color);
}

.toast.toast-warning {
    border-left-color: var(--warning-color);
}

.toast.toast-info {
    border-left-color: var(--primary-color);
}

.toast-message {
    color: var(--text-color);
    padding-right: 1.5rem;
}

.toast-close {
    position: absolute;
    top: 0.55rem;
    right: 0.65rem;
    border: none;
    background: transparent;
    color: var(--text-light);
    cursor: pointer;
    font-size: 1.1rem;
    line-height: 1;
}

.toast-progress {
    position: absolute;
    left: 0;
    bottom: 0;
    height: 4px;
    width: 100%;
    transform-origin: left center;
    animation: toast-progress 5s linear forwards;
    background-color: var(--primary-color);
}

.toast.toast-success .toast-progress {
    background-color: var(--secondary-color);
}

.toast.toast-error .toast-progress {
    background-color: var(--danger-color);
}

.toast.toast-warning .toast-progress {
    background-color: var(--warning-color);
}

@keyframes toast-slide-in {
    from {
        opacity: 0;
        transform: translateX(16px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes toast-progress {
    from {
        transform: scaleX(1);
    }
    to {
        transform: scaleX(0);
    }
}

/* Home Page */
.hero {
    color: #746f75;
    padding: 3rem;
    border-radius: 8px;
    margin-bottom: 2rem;
    text-align: center;
}

.hero h2 {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.hero p {
    font-size: 1.2rem;
    opacity: 0.9;
}

.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin: 2rem 0;
}

.feature-card {
    background-color: white;
    padding: 1.5rem;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s;
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.15);
}

.feature-card h4 {
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

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

.info-section,
.research-section,
.quick-start {
    background-color: white;
    padding: 2rem;
    margin: 2rem 0;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.info-section h3,
.research-section h3,
.quick-start h3 {
    color: var(--primary-color);
    margin-bottom: 1.5rem;
}

.research-section h4 {
    color: var(--text-color);
    margin: 1rem 0 0.5rem;
    margin-top: 1.5rem;
}

pre {
    background-color: var(--light-bg);
    padding: 1rem;
    border-radius: 4px;
    overflow-x: auto;
    margin: 1rem 0;
    font-family: 'Courier New', monospace;
    font-size: 0.9rem;
}

.quick-start ol {
    margin-left: 2rem;
    margin-bottom: 1.5rem;
}

.quick-start li {
    margin-bottom: 0.5rem;
}

.quick-start .btn {
    margin-top: 1rem;
}

/* Student Form */
.student-card {
    background-color: white;
    padding: 1.5rem;
    margin: 1rem 0;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    cursor: pointer;
    transition: box-shadow 0.3s;
}

.student-card:hover {
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.15);
}

.student-name {
    font-weight: bold;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.student-info-text {
    color: var(--text-light);
    font-size: 0.9rem;
}

/* Result Page */
.student-info {
    background-color: white;
    padding: 1.5rem;
    margin-bottom: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    border-left: 4px solid var(--primary-color);
}

.result-section {
    background-color: white;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.eligible-section {
    border-left: 4px solid var(--warning-color);
}

.recommended-section {
    border-left: 4px solid var(--secondary-color);
    background-color: #f1f8f4;
}

.score-high {
    color: var(--secondary-color);
    font-weight: bold;
}

.score-low {
    color: var(--text-light);
}

.explanation-section {
    border-left: 4px solid var(--primary-color);
}

details {
    margin: 1rem 0;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    padding: 1rem;
}

summary {
    cursor: pointer;
    font-weight: 600;
    color: var(--primary-color);
    padding: 0.5rem;
}

summary:hover {
    background-color: var(--light-bg);
    border-radius: 4px;
}

/* Footer */
footer {
    flex-shrink: 0;
    background-color: var(--text-color);
    color: white;
    text-align: center;
    padding: 2rem;
    margin-top: auto;
    border-top: 4px solid var(--primary-color);
}

/* Responsive */
@media (max-width: 768px) {
    .hero {
        padding: 1.5rem;
    }

    .hero h2 {
        font-size: 1.5rem;
    }

    .navbar .container {
        flex-direction: column;
        gap: 1rem;
    }

    .brand-logo-img {
        height: 32px;
    }

    .nav-links {
        gap: 1rem;
    }

    .toast-container {
        top: auto;
        right: 0.75rem;
        bottom: 0.75rem;
        width: min(320px, calc(100vw - 1rem));
    }

    th,
    td {
        padding: 0.75rem;
    }

    table {
        font-size: 0.9rem;
    }

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

/* ==========================================================================
   ALGORITHM DETAILS & EXPLANATION TABS STYLE
   ========================================================================== */

.algorithm-details h3 {
    font-size: 1.3rem;
    color: #0d47a1;
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 8px;
    border-bottom: 2px solid #e3f2fd;
    padding-bottom: 8px;
}

.tabs-container {
    background: #ffffff;
    border-radius: 12px;
    border: 1px solid rgba(0, 0, 0, 0.06);
    overflow: hidden;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.02);
}

.tabs-header {
    display: flex;
    background-color: #f8f9fa;
    border-bottom: 1px solid rgba(0, 0, 0, 0.06);
    padding: 0 10px;
}

.tab-btn {
    background: none;
    border: none;
    padding: 14px 20px;
    font-size: 0.95rem;
    font-weight: 600;
    color: #495057;
    cursor: pointer;
    transition: all 0.25s ease;
    border-bottom: 3px solid transparent;
    outline: none;
}

.tab-btn:hover {
    color: #0d47a1;
    background-color: rgba(13, 71, 161, 0.04);
}

.tab-btn.active {
    color: #0d47a1;
    border-bottom-color: #0d47a1;
    background-color: #ffffff;
}

.tabs-content {
    padding: 24px;
}

.tab-pane {
    display: none;
    animation: tabFadeIn 0.3s ease;
}

.tab-pane.active {
    display: block;
}

@keyframes tabFadeIn {
    from { opacity: 0; transform: translateY(4px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Reasons Dashboard (Tab 1) */
.reasons-dashboard {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 16px;
    margin-top: 10px;
}

.reasons-card {
    background: #ffffff;
    border-radius: 10px;
    border: 1px solid #e9ecef;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.03);
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    text-align: left;
}

.reasons-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(13, 71, 161, 0.08);
    border-color: rgba(13, 71, 161, 0.15);
}

.reasons-card-header {
    background: #f8f9fa;
    padding: 12px 16px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    border-bottom: 1px solid #e9ecef;
}

.course-code-tag {
    font-family: monospace;
    font-size: 0.9rem;
    font-weight: 700;
    color: #0d47a1;
    background-color: #e3f2fd;
    padding: 4px 8px;
    border-radius: 4px;
}

.course-name-text {
    font-size: 0.95rem;
    font-weight: 600;
    color: #212529;
    flex: 1;
    margin: 0 10px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.course-credits-tag {
    font-size: 0.85rem;
    font-weight: 600;
    color: #495057;
    background: #e9ecef;
    padding: 2px 6px;
    border-radius: 4px;
}

.reasons-card-body {
    padding: 16px;
    display: flex;
    flex-direction: column;
    gap: 12px;
    flex: 1;
}

.reasons-meta {
    display: flex;
    align-items: center;
    justify-content: space-between;
    font-size: 0.85rem;
}

.badge {
    display: inline-block;
    padding: 4px 10px;
    border-radius: 50px;
    font-weight: 600;
    font-size: 0.75rem;
    line-height: 1.2;
}

.badge-danger {
    background-color: #ffebee;
    color: #c62828;
    border: 1px solid #ffcdd2;
}

.badge-success {
    background-color: #e8f5e9;
    color: #2e7d32;
    border: 1px solid #c8e6c9;
}

.badge-warning {
    background-color: #fff8e1;
    color: #f57c00;
    border: 1px solid #ffe082;
}

.badge-info {
    background-color: #e3f2fd;
    color: #0d47a1;
    border: 1px solid #bbdefb;
}

.badge-secondary {
    background-color: #f1f3f5;
    color: #495057;
    border: 1px solid #e9ecef;
}

.priority-score-tag {
    color: #495057;
}

.priority-score-tag strong {
    color: #0d47a1;
    font-size: 1.05rem;
}

.reasons-list-container {
    display: flex;
    flex-direction: column;
    gap: 6px;
    font-size: 0.85rem;
}

.reasons-list-container strong {
    color: #495057;
}

.reasons-badges {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
}

.reason-badge {
    background: #f1f3f5;
    color: #495057;
    padding: 3px 8px;
    border-radius: 4px;
    font-size: 0.8rem;
    border: 1px solid #e9ecef;
}

/* Heuristic Tab (Tab 2) */
.heuristic-details-card {
    display: flex;
    flex-direction: column;
    gap: 20px;
    text-align: left;
}

.formula-box {
    background: linear-gradient(135deg, #0d47a1 0%, #1565c0 100%);
    color: #ffffff;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 4px 15px rgba(13, 71, 161, 0.15);
    text-align: center;
}

.formula-title {
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    opacity: 0.85;
}

.formula-math {
    font-size: 1.4rem;
    font-weight: 700;
    margin: 10px 0;
    font-family: 'Courier New', monospace;
}

.formula-submath {
    font-size: 1.1rem;
    opacity: 0.9;
    font-family: 'Courier New', monospace;
}

.formula-explanation-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

.explanation-item {
    display: flex;
    gap: 12px;
    padding: 16px;
    border-radius: 8px;
    border: 1px solid #e9ecef;
    background: #f8f9fa;
}

.explanation-item.primary { border-left: 4px solid #d32f2f; }
.explanation-item.secondary { border-left: 4px solid #1976d2; }
.explanation-item.warning { border-left: 4px solid #f57c00; }
.explanation-item.info { border-left: 4px solid #388e3c; }

.item-icon {
    font-size: 1.5rem;
    line-height: 1;
}

.item-text {
    font-size: 0.9rem;
    line-height: 1.4;
    color: #495057;
}

.item-text strong {
    color: #212529;
    display: block;
    margin-bottom: 4px;
}

/* Beam Search Tab (Tab 3) */
.beam-details-card {
    display: flex;
    flex-direction: column;
    gap: 20px;
    text-align: left;
}

.beam-metrics-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 16px;
}

.metric-card {
    background: #f8f9fa;
    border: 1px solid #e9ecef;
    border-radius: 8px;
    padding: 16px;
    text-align: center;
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.metric-label {
    font-size: 0.85rem;
    color: #6c757d;
    font-weight: 600;
}

.metric-value {
    font-size: 1.5rem;
    font-weight: 700;
    color: #0d47a1;
}

.metric-desc {
    font-size: 0.8rem;
    color: #868e96;
}

.beam-flow {
    background: #ffffff;
    border: 1px solid #e9ecef;
    border-radius: 8px;
    padding: 16px 20px;
}

.beam-flow h4 {
    font-size: 1rem;
    color: #495057;
    margin-bottom: 12px;
}

.beam-steps {
    margin-left: 20px;
    font-size: 0.9rem;
    color: #495057;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.beam-steps li {
    line-height: 1.4;
}

@media (max-width: 768px) {
    .formula-explanation-grid,
    .beam-metrics-grid {
        grid-template-columns: 1fr;
    }
    
    .tabs-header {
        overflow-x: auto;
        white-space: nowrap;
    }
    
    .tab-btn {
        padding: 10px 15px;
        font-size: 0.85rem;
    }
}

/* ==========================================================================
   Dashboard Landing Redesign
   ========================================================================== */
.dashboard-landing {
    animation: fadeInUp 0.6s ease-out;
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px 0;
}

/* Hero Section */
.hero-section {
    position: relative;
    background-color: #ffffff;
    background-image: 
        radial-gradient(circle at top right, rgba(2, 132, 199, 0.05), transparent 45%),
        radial-gradient(circle at bottom left, rgba(13, 148, 136, 0.05), transparent 45%),
        radial-gradient(rgba(13, 71, 161, 0.06) 1px, transparent 1px);
    background-size: 100% 100%, 100% 100%, 20px 20px;
    padding: 50px 40px;
    border-radius: 16px;
    border: 1px solid rgba(13, 71, 161, 0.08);
    box-shadow: 0 10px 30px rgba(13, 71, 161, 0.04);
    overflow: hidden;
    margin-bottom: 36px;
    text-align: center;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.hero-badge {
    background: #e0f2fe;
    color: #0369a1;
    font-size: 0.72rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 1.5px;
    padding: 5px 14px;
    border-radius: 50px;
    border: 1px solid rgba(3, 105, 161, 0.12);
    margin-bottom: 18px;
    display: inline-block;
}

.hero-section h1 {
    font-size: 2.2rem;
    font-weight: 800;
    line-height: 1.35;
    margin-bottom: 16px;
    max-width: 750px;
    color: #0f172a;
}

.hero-section h1 .highlight-text {
    background: linear-gradient(135deg, #0284c7 0%, #0d9488 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    display: inline-block;
}

.hero-section p {
    font-size: 0.95rem;
    line-height: 1.6;
    color: #475569;
    max-width: 640px;
    margin-bottom: 28px;
}

.hero-actions {
    z-index: 2;
}

.btn-premium-action {
    background: linear-gradient(135deg, #0284c7 0%, #0369a1 100%);
    color: #ffffff;
    font-weight: 700;
    padding: 11px 26px;
    border-radius: 50px;
    font-size: 0.92rem;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    box-shadow: 0 4px 14px rgba(2, 132, 199, 0.25);
    transition: all 0.3s cubic-bezier(0.165, 0.84, 0.44, 1);
}

.btn-premium-action:hover {
    background: linear-gradient(135deg, #0ea5e9 0%, #0284c7 100%);
    color: #ffffff;
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(2, 132, 199, 0.35);
}

.btn-premium-action:hover .arrow-icon {
    transform: translateX(4px);
}

.arrow-icon {
    transition: transform 0.2s ease;
    display: inline-block;
}

/* Hero Decorative Circles */
.hero-decorative-circle {
    position: absolute;
    border-radius: 50%;
    filter: blur(90px);
    pointer-events: none;
    opacity: 0.25;
}

.circle-1 {
    width: 250px;
    height: 250px;
    background: #38bdf8;
    top: -80px;
    left: -50px;
}

.circle-2 {
    width: 200px;
    height: 200px;
    background: #2dd4bf;
    bottom: -60px;
    right: -30px;
}

/* Features Section */
.features-section {
    margin-bottom: 56px;
}

.section-title-wrapper {
    margin-bottom: 32px;
}

.section-title-wrapper.text-center {
    text-align: center;
}

.sub-title {
    color: #1565c0;
    font-weight: 700;
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    display: block;
    margin-bottom: 8px;
}

.features-section h2, 
.quickstart-section h2 {
    font-size: 2rem;
    color: #212529;
    font-weight: 800;
    margin-top: 0;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 24px;
}

.feature-card {
    background: #ffffff;
    border: 1px solid rgba(0, 0, 0, 0.05);
    border-radius: 16px;
    padding: 30px 24px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.02);
    transition: all 0.3s cubic-bezier(0.165, 0.84, 0.44, 1);
    display: flex;
    flex-direction: column;
    align-items: flex-start;
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.08);
    border-color: rgba(13, 71, 161, 0.15);
}

.feature-icon-wrapper {
    width: 56px;
    height: 56px;
    border-radius: 12px;
    display: grid;
    place-items: center;
    color: white;
    margin-bottom: 20px;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
}

.blue-grad {
    background: linear-gradient(135deg, #0284c7, #0d47a1);
}

.green-grad {
    background: linear-gradient(135deg, #10b981, #1b5e20);
}

.purple-grad {
    background: linear-gradient(135deg, #8b5cf6, #4a148c);
}

.orange-grad {
    background: linear-gradient(135deg, #f59e0b, #e65100);
}

.feature-card h3 {
    font-size: 1.25rem;
    color: #212529;
    font-weight: 700;
    margin-bottom: 12px;
    margin-top: 0;
}

.feature-card p {
    font-size: 0.95rem;
    color: #6c757d;
    line-height: 1.6;
    margin: 0;
}

/* Quick Start Timeline */
.quickstart-section {
    background: #ffffff;
    border: 1px solid rgba(0, 0, 0, 0.05);
    padding: 48px;
    border-radius: 20px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.02);
    margin-bottom: 40px;
}

.steps-timeline {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 16px;
    margin-top: 40px;
    margin-bottom: 40px;
}

.timeline-step {
    flex: 1;
    text-align: center;
    position: relative;
    padding: 10px;
}

.step-badge {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: #e3f2fd;
    color: #0d47a1;
    font-weight: 800;
    font-size: 1.1rem;
    display: grid;
    place-items: center;
    margin: 0 auto 16px;
    border: 3px solid #ffffff;
    box-shadow: 0 0 0 3px #bbdefb;
    transition: all 0.3s ease;
}

.timeline-step:hover .step-badge {
    background: #0d47a1;
    color: #ffffff;
    box-shadow: 0 0 0 3px #90caf9;
}

.timeline-step h4 {
    font-size: 1.1rem;
    font-weight: 700;
    color: #212529;
    margin-bottom: 8px;
    margin-top: 0;
}

.timeline-step p {
    font-size: 0.9rem;
    color: #6c757d;
    line-height: 1.5;
    margin: 0;
}

.timeline-divider {
    color: #bbdefb;
    display: flex;
    align-self: center;
    margin-bottom: 48px;
    flex-shrink: 0;
}

.quickstart-action {
    text-align: center;
    margin-top: 16px;
}

.btn-premium-action-large {
    background: linear-gradient(135deg, #0d47a1 0%, #1565c0 100%);
    color: white;
    font-weight: 700;
    padding: 16px 40px;
    border-radius: 50px;
    font-size: 1.1rem;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    box-shadow: 0 6px 20px rgba(13, 71, 161, 0.25);
    transition: all 0.3s cubic-bezier(0.165, 0.84, 0.44, 1);
}

.btn-premium-action-large:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(13, 71, 161, 0.35);
}

.btn-premium-action-large:hover .arrow-icon {
    transform: translateX(4px);
}

/* Animations */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Responsive */
@media (max-width: 992px) {
    .steps-timeline {
        flex-direction: column;
        align-items: center;
        gap: 32px;
    }

    .timeline-divider {
        display: none;
    }

    .timeline-step {
        max-width: 400px;
    }
}

@media (max-width: 768px) {
    .hero-section {
        padding: 50px 30px;
    }

    .hero-section h1 {
        font-size: 2rem;
    }

    .hero-section p {
        font-size: 1rem;
    }

    .quickstart-section {
        padding: 24px;
    }
}

/* ==========================================================================
   PREMIUM BADGES COMPONENT
   ========================================================================== */
.badge-custom {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.35rem 0.75rem;
    font-size: 0.75rem;
    font-weight: 600;
    line-height: 1.2;
    border-radius: 9999px;
    letter-spacing: 0.02em;
    white-space: nowrap;
    transition: all 0.2s ease;
}

/* Kiểu Glassmorphism (Nền mờ đục nhẹ, text đậm) */
.badge-glass-primary {
    background-color: rgba(13, 71, 161, 0.1);
    color: #0d47a1;
    border: 1px solid rgba(13, 71, 161, 0.2);
}
.badge-glass-success {
    background-color: rgba(21, 128, 61, 0.1);
    color: #15803d;
    border: 1px solid rgba(21, 128, 61, 0.2);
}
.badge-glass-danger {
    background-color: rgba(185, 28, 28, 0.1);
    color: #b91c1c;
    border: 1px solid rgba(185, 28, 28, 0.2);
}
.badge-glass-warning {
    background-color: rgba(194, 65, 12, 0.1);
    color: #c2410c;
    border: 1px solid rgba(194, 65, 12, 0.2);
}
.badge-glass-info {
    background-color: rgba(14, 116, 144, 0.1);
    color: #0e7490;
    border: 1px solid rgba(14, 116, 144, 0.2);
}
.badge-glass-gray {
    background-color: rgba(71, 85, 105, 0.1);
    color: #475569;
    border: 1px solid rgba(71, 85, 105, 0.2);
}

/* Micro-animations khi hover */
.badge-custom:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    filter: brightness(1.02);
}