:root {
    --app-bg: #f4f7fb;
    --app-card: #ffffff;
    --app-text: #0f172a;
    --app-muted: #64748b;
    --app-border: rgba(148, 163, 184, 0.24);

    --app-primary: #4f46e5;
    --app-primary-2: #6366f1;
    --app-info: #06b6d4;
    --app-success: #10b981;
    --app-danger: #ef4444;
    --app-warning: #f59e0b;

    --app-radius-sm: 14px;
    --app-radius-md: 20px;
    --app-radius-lg: 28px;
    --app-radius-xl: 34px;

    --app-shadow-sm: 0 8px 22px rgba(15, 23, 42, 0.06);
    --app-shadow-md: 0 18px 42px rgba(15, 23, 42, 0.08);
    --app-shadow-lg: 0 26px 70px rgba(15, 23, 42, 0.13);
}

* {
    box-sizing: border-box;
}

html {
    min-height: 100%;
    scroll-behavior: smooth;
}

body {
    min-height: 100vh;
    margin: 0;
    background:
        radial-gradient(circle at top left, rgba(79, 70, 229, 0.08), transparent 28%),
        radial-gradient(circle at bottom right, rgba(6, 182, 212, 0.07), transparent 30%),
        var(--app-bg);
    color: var(--app-text);
    font-family: "Inter", "Segoe UI", Arial, Helvetica, sans-serif;
    font-size: 16px;
    line-height: 1.45;
    text-rendering: geometricPrecision;
    -webkit-font-smoothing: antialiased;
}

a {
    color: inherit;
}

button,
input,
select,
textarea {
    font: inherit;
}

button {
    cursor: pointer;
}

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

.public-main {
    min-height: 100vh;
}

/* -------------------- FORMS -------------------- */

input,
select,
textarea {
    color: var(--app-text);
}

input::placeholder,
textarea::placeholder {
    color: #94a3b8;
}

input:disabled,
select:disabled,
textarea:disabled {
    opacity: 0.72;
    cursor: not-allowed;
}

.form-control,
input[type="text"],
input[type="password"],
input[type="email"],
input[type="number"],
input[type="tel"],
input[type="search"],
select,
textarea {
    border: 1px solid #e5e7eb;
    background: #f8fafc;
    color: var(--app-text);
    border-radius: 18px;
    min-height: 50px;
    outline: none;
    transition: 0.18s ease;
}

input[type="text"],
input[type="password"],
input[type="email"],
input[type="number"],
input[type="tel"],
input[type="search"],
select {
    padding: 0 14px;
}

textarea {
    padding: 14px;
    resize: vertical;
}

.form-control:focus,
input[type="text"]:focus,
input[type="password"]:focus,
input[type="email"]:focus,
input[type="number"]:focus,
input[type="tel"]:focus,
input[type="search"]:focus,
select:focus,
textarea:focus {
    background: #ffffff;
    border-color: var(--app-primary);
    box-shadow: 0 0 0 5px rgba(79, 70, 229, 0.11);
}

label {
    color: var(--app-text);
    font-weight: 850;
}

/* -------------------- BUTTON BASE -------------------- */

.btn-main,
.btn-primary,
.btn-save,
.login-button,
.submit-form button {
    border: 0;
    background: linear-gradient(135deg, var(--app-primary), var(--app-info));
    color: #fff;
    box-shadow: 0 16px 34px rgba(79, 70, 229, 0.23);
    transition: 0.18s ease;
}

.btn-main:hover,
.btn-primary:hover,
.btn-save:hover,
.login-button:hover,
.submit-form button:hover {
    transform: translateY(-1px);
    filter: brightness(1.04);
}

.btn-back,
.btn-secondary,
.edit-btn {
    background: #eef2ff;
    color: #4338ca;
    border: 1px solid rgba(79, 70, 229, 0.10);
    transition: 0.18s ease;
}

.btn-back:hover,
.btn-secondary:hover,
.edit-btn:hover {
    background: #e0e7ff;
    transform: translateY(-1px);
}

.btn-delete,
.btn-danger,
.delete-btn {
    background: #fee2e2;
    color: #991b1b;
    border: 1px solid rgba(239, 68, 68, 0.10);
    transition: 0.18s ease;
}

.btn-delete:hover,
.btn-danger:hover,
.delete-btn:hover {
    background: #fecaca;
    transform: translateY(-1px);
}

/* -------------------- ALERTS -------------------- */

.alert {
    border: 0;
    border-radius: 18px;
    padding: 14px 18px;
    font-weight: 850;
    box-shadow: var(--app-shadow-sm);
}

.alert-success {
    background: #dcfce7;
    color: #166534;
}

.alert-danger {
    background: #fee2e2;
    color: #991b1b;
}

.alert-warning {
    background: #ffedd5;
    color: #9a3412;
}

.text-danger,
.field-validation-error,
.validation-summary-errors {
    color: #dc2626;
    font-weight: 850;
}

.validation-summary-errors ul {
    margin: 0;
    padding-left: 18px;
}

/* -------------------- CARDS / TABLES -------------------- */

.card,
.panel,
.table-card,
.form-card,
.page-card,
.stat-card,
.user-card,
.class-card,
.lesson-card,
.announcement-card,
.homework-card,
.request-card,
.empty-box,
.empty-state {
    background: rgba(255, 255, 255, 0.88);
    border: 1px solid rgba(255, 255, 255, 0.72);
    box-shadow: var(--app-shadow-md);
}

table {
    border-collapse: collapse;
}

th {
    color: #475569;
    font-weight: 950;
}

td {
    color: var(--app-text);
}

/* -------------------- GLOBAL DELETE MODAL SUPPORT -------------------- */

.delete-confirm-backdrop,
.delete-modal-backdrop {
    position: fixed;
    inset: 0;
    display: none;
    align-items: center;
    justify-content: center;
    background: rgba(15, 23, 42, 0.62);
    z-index: 99999;
    padding: 18px;
    backdrop-filter: blur(8px);
}

.delete-confirm-backdrop.show,
.delete-modal-backdrop.show {
    display: flex;
}

.delete-confirm-card,
.delete-modal-card {
    width: 100%;
    max-width: 430px;
    background: #ffffff;
    border-radius: 30px;
    padding: 28px;
    text-align: center;
    box-shadow: 0 30px 90px rgba(0, 0, 0, 0.34);
}

.delete-confirm-icon,
.delete-modal-icon {
    width: 74px;
    height: 74px;
    border-radius: 24px;
    background: #fee2e2;
    color: #991b1b;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 34px;
    margin: 0 auto 16px;
}

.delete-confirm-card h3,
.delete-modal-card h3 {
    margin: 0;
    color: #0f172a;
    font-size: 25px;
    font-weight: 950;
}

.delete-confirm-card p,
.delete-modal-card p {
    color: #64748b;
    font-weight: 800;
    line-height: 1.5;
}

.delete-confirm-actions,
.delete-modal-actions {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
    margin-top: 18px;
}

.cancel-modal-btn,
.confirm-modal-btn,
.delete-cancel-btn,
.delete-confirm-btn {
    min-height: 52px;
    border: 0;
    border-radius: 16px;
    font-weight: 950;
}

.cancel-modal-btn,
.delete-cancel-btn {
    background: #eef2ff;
    color: #4338ca;
}

.confirm-modal-btn,
.delete-confirm-btn {
    background: #ef4444;
    color: #fff;
}

/* -------------------- SCROLLBAR -------------------- */

::-webkit-scrollbar {
    width: 11px;
    height: 11px;
}

::-webkit-scrollbar-track {
    background: #eef2f7;
}

::-webkit-scrollbar-thumb {
    background: #cbd5e1;
    border-radius: 999px;
    border: 2px solid #eef2f7;
}

::-webkit-scrollbar-thumb:hover {
    background: #94a3b8;
}

/* -------------------- RESPONSIVE HELPERS -------------------- */

@media (max-width: 768px) {
    body {
        font-size: 15px;
    }

    .delete-confirm-actions,
    .delete-modal-actions {
        grid-template-columns: 1fr;
    }
}