:root {
    --bg-gradient: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    --panel-bg: rgba(255, 255, 255, 0.85);
    --panel-border: rgba(255, 255, 255, 0.4);
    --text-main: #1e293b;
    --text-muted: #64748b;
    --btn-bg: linear-gradient(135deg, #4f46e5 0%, #3b82f6 100%);
    --btn-text: #ffffff;
    --btn-shadow: rgba(79, 70, 229, 0.3);
    --sidebar-bg: rgba(255, 255, 255, 0.95);
    --toggle-bg: #e2e8f0;
    --blur-strength: 12px;
    --shadow: 0 20px 40px rgba(0, 0, 0, 0.05);
}

[data-theme="dark"] {
    --bg-gradient: linear-gradient(135deg, #0f172a 0%, #1e1e38 100%);
    --panel-bg: rgba(30, 41, 59, 0.7);
    --panel-border: rgba(255, 255, 255, 0.05);
    --text-main: #f8f9fa;
    --text-muted: #94a3b8;
    --btn-bg: linear-gradient(135deg, #6366f1 0%, #a855f7 100%);
    --btn-text: #ffffff;
    --btn-shadow: rgba(99, 102, 241, 0.4);
    --sidebar-bg: rgba(15, 23, 42, 0.95);
    --toggle-bg: #334155;
    --shadow: 0 20px 40px rgba(0, 0, 0, 0.4);
}

* {
    box-sizing: border-box;
    transition: background 0.3s, color 0.3s, border-color 0.3s;
}

body {
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    background: var(--bg-gradient);
    background-attachment: fixed;
    color: var(--text-main);
    margin: 0;
    padding: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    overflow-x: hidden;
}

.main-card {
    background: var(--panel-bg);
    backdrop-filter: blur(var(--blur-strength));
    -webkit-backdrop-filter: blur(var(--blur-strength));
    border: 1px solid var(--panel-border);
    padding: 3rem 2rem 1.5rem 2rem;
    border-radius: 24px;
    box-shadow: var(--shadow);
    text-align: center;
    width: 90%;
    max-width: 450px;
    z-index: 1;
    display: flex;
    flex-direction: column;
}

h1 {
    font-size: 2.2rem;
    font-weight: 800;
    margin: 0 0 0.5rem 0;
    letter-spacing: -0.05em;
}

.subtitle {
    color: var(--text-muted);
    font-size: 1rem;
    margin-bottom: 2rem;
}

.copyright {
    margin-top: 2rem;
    font-size: 0.8rem;
    color: var(--text-muted);
    opacity: 0.7;
}

.menu-trigger {
    position: fixed;
    top: 20px;
    left: 20px;
    background: var(--panel-bg);
    border: 1px solid var(--panel-border);
    width: 48px;
    height: 48px;
    border-radius: 12px;
    cursor: pointer;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 5px;
    z-index: 10;
    box-shadow: var(--shadow);
}

.menu-trigger span {
    display: block;
    width: 22px;
    height: 2.5px;
    background-color: var(--text-main);
    border-radius: 2px;
    transition: transform 0.3s, opacity 0.3s;
}

.menu-trigger.open span:nth-child(1) {
    transform: translateY(7.5px) rotate(45deg);
}
.menu-trigger.open span:nth-child(2) {
    opacity: 0;
}
.menu-trigger.open span:nth-child(3) {
    transform: translateY(-7.5px) rotate(-45deg);
}

.sidebar {
    position: fixed;
    top: 0;
    left: -320px;
    width: 300px;
    height: 100vh;
    background: var(--sidebar-bg);
    backdrop-filter: blur(var(--blur-strength));
    box-shadow: var(--shadow);
    z-index: 9;
    padding: 90px 24px 24px 24px;
    display: flex;
    flex-direction: column;
    gap: 20px;
    transition: left 0.4s cubic-bezier(0.16, 1, 0.3, 1);
}

.sidebar.open {
    left: 0;
}

.sidebar-title {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 5px;
}

#button-container {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.link-button {
    display: block;
    background: var(--btn-bg);
    color: var(--btn-text);
    text-decoration: none;
    padding: 14px 20px;
    font-weight: 600;
    border-radius: 14px;
    text-align: center;
    box-shadow: 0 4px 12px var(--btn-shadow);
    transition: transform 0.2s, box-shadow 0.2s;
}

.link-button:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 20px var(--btn-shadow);
}

.link-button:active {
    transform: translateY(-1px);
}

.theme-section {
    margin-top: auto;
    border-top: 1px solid var(--panel-border);
    padding-top: 20px;
}

.theme-toggle {
    width: 100%;
    background-color: var(--toggle-bg);
    border: none;
    padding: 12px;
    border-radius: 14px;
    cursor: pointer;
    font-weight: 600;
    font-size: 0.95rem;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 8px;
    color: var(--text-main);
}

.overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: rgba(0, 0, 0, 0.2);
    opacity: 0;
    pointer-events: none;
    z-index: 8;
    transition: opacity 0.4s;
}

.overlay.open {
    opacity: 1;
    pointer-events: auto;
}