diff --git a/app/assets/stylesheets/application.scss b/app/assets/stylesheets/application.scss
index b756759a..2f52829b 100644
--- a/app/assets/stylesheets/application.scss
+++ b/app/assets/stylesheets/application.scss
@@ -25,6 +25,10 @@ $spacers: (
   2-plus: 0.75rem
 );
 
+$sizes: (
+  "70ch": 70ch,
+);
+
 @import "bootstrap";
 @import "editor";
 
@@ -404,6 +408,8 @@ $bezier: cubic-bezier(0.75, 0, 0.25, 1);
     @each $prop, $abbrev in (width: w, height: h) {
       @each $size, $length in $sizes {
         .#{$abbrev}-#{$grid-breakpoint}-#{$size} { #{$prop}: $length !important; }
+        .min-#{$abbrev}-#{$grid-breakpoint}-#{$size} { min-#{$prop}: $length !important; }
+        .max-#{$abbrev}-#{$grid-breakpoint}-#{$size} { max-#{$prop}: $length !important; }
       }
     }
 
diff --git a/app/views/bootstrap/_alert.haml b/app/views/bootstrap/_alert.haml
new file mode 100644
index 00000000..85bcbe84
--- /dev/null
+++ b/app/views/bootstrap/_alert.haml
@@ -0,0 +1,2 @@
+.alert.alert-primary.mx-auto.content.max-w-md-70ch{ role: 'alert', class: local_assigns[:class] }
+  = yield
diff --git a/app/views/collaborations/collaborate.haml b/app/views/collaborations/collaborate.haml
index 50cad809..4d43ad7e 100644
--- a/app/views/collaborations/collaborate.haml
+++ b/app/views/collaborations/collaborate.haml
@@ -11,7 +11,6 @@
       url: site_collaborate_path(@site),
       method: :post) do |f|
       - unless current_usuarie
-        = render 'layouts/flash'
         .form-group
           = f.label :email
           = f.email_field :email, autofocus: true, autocomplete: 'email',
diff --git a/app/views/devise/confirmations/new.haml b/app/views/devise/confirmations/new.haml
index 59568cb7..bc2f77bb 100644
--- a/app/views/devise/confirmations/new.haml
+++ b/app/views/devise/confirmations/new.haml
@@ -1,6 +1,8 @@
 = content_for :body do
   - 'black-bg'
 
+= render 'devise/shared/error_messages', resource: resource
+
 .row.align-items-center.justify-content-center.full-height
   .col-md-4.align-self-center
     .sr-only
@@ -11,8 +13,6 @@
       url: confirmation_path(resource_name),
       html: { method: :post }) do |f|
 
-      = render 'devise/shared/error_messages', resource: resource
-
       :ruby
         value = if resource.pending_reconfirmation?
                   resource.unconfirmed_email
diff --git a/app/views/devise/invitations/edit.haml b/app/views/devise/invitations/edit.haml
index 565429a8..ed4980ef 100644
--- a/app/views/devise/invitations/edit.haml
+++ b/app/views/devise/invitations/edit.haml
@@ -1,6 +1,8 @@
 = content_for :body do
   - 'black-bg'
 
+= render 'devise/shared/error_messages', resource: resource
+
 .row.align-items-center.justify-content-center.full-height
   .col-md-5.align-self-center
     %h2= t 'devise.invitations.edit.header'
@@ -8,7 +10,6 @@
       as: resource_name,
       url: invitation_path(resource_name),
       html: { method: :put }) do |f|
-      = render 'devise/shared/error_messages', resource: resource
       = f.hidden_field :invitation_token, readonly: true
       - if f.object.class.require_password_on_accepting
         .form-group
diff --git a/app/views/devise/invitations/new.haml b/app/views/devise/invitations/new.haml
index 44ceec2e..4ebb8fa7 100644
--- a/app/views/devise/invitations/new.haml
+++ b/app/views/devise/invitations/new.haml
@@ -1,6 +1,8 @@
 = content_for :body do
   - 'black-bg'
 
+= render 'devise/shared/error_messages', resource: resource
+
 .row.align-items-center.justify-content-center.full-height
   .col-md-5.align-self-center
     %h2= t 'devise.invitations.new.header'
@@ -8,7 +10,6 @@
       as: resource_name,
       url: invitation_path(resource_name),
       html: { method: :post }) do |f|
-      = render 'devise/shared/error_messages', resource: resource
       - resource.class.invite_key_fields.each do |field|
         .form-group
           = f.label field
diff --git a/app/views/devise/passwords/edit.haml b/app/views/devise/passwords/edit.haml
index 7f7b16fb..3a8843c0 100644
--- a/app/views/devise/passwords/edit.haml
+++ b/app/views/devise/passwords/edit.haml
@@ -1,6 +1,8 @@
 = content_for :body do
   - 'black-bg'
 
+= render 'devise/shared/error_messages', resource: resource
+
 .row.align-items-center.justify-content-center.full-height
   .col-md-5.align-self-center
     .sr-only
@@ -10,7 +12,6 @@
     = form_for(resource, as: resource_name,
       url: password_path(resource_name),
       html: { method: :put }) do |f|
-      = render 'devise/shared/error_messages', resource: resource
 
       = f.hidden_field :reset_password_token
 
diff --git a/app/views/devise/passwords/new.haml b/app/views/devise/passwords/new.haml
index 3c80b8a0..08dd8d2e 100644
--- a/app/views/devise/passwords/new.haml
+++ b/app/views/devise/passwords/new.haml
@@ -1,6 +1,8 @@
 = content_for :body do
   - 'black-bg'
 
+= render 'devise/shared/error_messages', resource: resource
+
 .row.align-items-center.justify-content-center.full-height
   .col-md-5.align-self-center
     .sr-only
@@ -11,7 +13,6 @@
       as: resource_name,
       url: password_path(resource_name),
       html: { method: :post }) do |f|
-      = render 'devise/shared/error_messages', resource: resource
       .form-group
         = f.label :email, class: 'sr-only'
         = f.email_field :email, autofocus: true, autocomplete: 'email',
diff --git a/app/views/devise/registrations/edit.haml b/app/views/devise/registrations/edit.haml
index 6a25da65..92699ab8 100644
--- a/app/views/devise/registrations/edit.haml
+++ b/app/views/devise/registrations/edit.haml
@@ -3,6 +3,8 @@
 = content_for :body do
   - 'black-bg'
 
+= render 'devise/shared/error_messages', resource: resource
+
 .row.align-items-center.justify-content-center.full-height
   .col-md-6.align-self-center
     %h2= t('.title')
@@ -11,8 +13,6 @@
       url: registration_path(resource_name),
       html: { method: :put }) do |f|
 
-      = render 'devise/shared/error_messages', resource: resource
-
       .form-group
         = f.label :email
         = f.email_field :email, autofocus: true, autocomplete: 'email',
diff --git a/app/views/devise/registrations/new.haml b/app/views/devise/registrations/new.haml
index 21676556..e6bda964 100644
--- a/app/views/devise/registrations/new.haml
+++ b/app/views/devise/registrations/new.haml
@@ -1,6 +1,8 @@
 = content_for :body do
   - 'black-bg'
 
+= render 'devise/shared/error_messages', resource: resource
+
 .row.align-items-center.justify-content-center.full-height
   .col-md-5.align-self-center
     %h2= t('.sign_up')
@@ -10,8 +12,6 @@
       as: resource_name,
       url: registration_path(resource_name, params: { locale: params[:locale] })) do |f|
 
-      = render 'devise/shared/error_messages', resource: resource
-
       .form-group
         = f.label :email, class: 'sr-only'
         = f.email_field :email, autofocus: true, autocomplete: 'email',
diff --git a/app/views/devise/sessions/new.haml b/app/views/devise/sessions/new.haml
index b5223e5f..9b396187 100644
--- a/app/views/devise/sessions/new.haml
+++ b/app/views/devise/sessions/new.haml
@@ -3,8 +3,6 @@
 
 .row.align-items-center.justify-content-center.full-height
   .col-md-5.align-self-center
-    = render 'layouts/flash'
-
     .sr-only
       %h2= t('.sign_in')
       %p= t('.help')
diff --git a/app/views/devise/shared/_error_messages.haml b/app/views/devise/shared/_error_messages.haml
index a921fd61..64340e4f 100644
--- a/app/views/devise/shared/_error_messages.haml
+++ b/app/views/devise/shared/_error_messages.haml
@@ -1,9 +1,4 @@
 - if resource.errors.any?
-  #error_explanation
-    %h2
-      = I18n.t("errors.messages.not_saved",                 |
-        count: resource.errors.count,                       |
-        resource: resource.class.model_name.human.downcase) |
-    %ul
-      - resource.errors.full_messages.each do |message|
-        %li= message
+  = render 'bootstrap/alert' do
+    - resource.errors.full_messages.each do |message|
+      %p= message
diff --git a/app/views/devise/unlocks/new.haml b/app/views/devise/unlocks/new.haml
index ac511115..09468a52 100644
--- a/app/views/devise/unlocks/new.haml
+++ b/app/views/devise/unlocks/new.haml
@@ -1,6 +1,8 @@
 = content_for :body do
   - 'black-bg'
 
+= render 'devise/shared/error_messages', resource: resource
+
 .row.align-items-center.justify-content-center.full-height
   .col-md-5.align-self-center
     .sr-only
@@ -11,7 +13,6 @@
       as: resource_name,
       url: unlock_path(resource_name),
       html: { method: :post }) do |f|
-      = render 'devise/shared/error_messages', resource: resource
       .form-group
         = f.label :email, class: 'sr-only'
         = f.email_field :email, autofocus: true, autocomplete: 'email',
diff --git a/app/views/invitadxs/show.haml b/app/views/invitadxs/show.haml
index e1d47288..0c23522b 100644
--- a/app/views/invitadxs/show.haml
+++ b/app/views/invitadxs/show.haml
@@ -1,4 +1,4 @@
 .row.align-items-center.justify-content-center.full-height
   .col-md-6.align-self-center
-    .alert{role: 'alert', class: "alert-success"}
+    = render 'bootstrap/alert' do
       = t('.confirmation_sent')
diff --git a/app/views/layouts/_flash.haml b/app/views/layouts/_flash.haml
index 149f946f..7bd7ec0b 100644
--- a/app/views/layouts/_flash.haml
+++ b/app/views/layouts/_flash.haml
@@ -1,3 +1,4 @@
 - flash.each do |type, message|
   - unless type == 'js'
-    .alert{ role: 'alert', class: "alert-#{type}" }= message
+    = render 'bootstrap/alert' do
+      = message
diff --git a/app/views/layouts/_help.haml b/app/views/layouts/_help.haml
index 7a821e2d..6800b524 100644
--- a/app/views/layouts/_help.haml
+++ b/app/views/layouts/_help.haml
@@ -1,3 +1,4 @@
+-# DEPRECADO
 .alert.alert-info.alert-dismissible.fade.show{role: 'alert'}
   - if help.respond_to? :each
     %ul
diff --git a/app/views/layouts/application.html.haml b/app/views/layouts/application.html.haml
index 85d5ab22..965a856f 100644
--- a/app/views/layouts/application.html.haml
+++ b/app/views/layouts/application.html.haml
@@ -21,6 +21,9 @@
   %body{ class: yield(:body) }
     .container-fluid#sutty
       = render 'layouts/breadcrumb'
+      = render 'layouts/flash'
+
       = yield
+
       - if flash[:js]
         .js-flash.d-none{ data: flash[:js] }
diff --git a/app/views/posts/_form.haml b/app/views/posts/_form.haml
index e46b2eda..7de0ea79 100644
--- a/app/views/posts/_form.haml
+++ b/app/views/posts/_form.haml
@@ -1,7 +1,9 @@
 - unless post.errors.empty?
-  .alert.alert-danger
-    %h4= t('.errors.title')
-    %p= t('.errors.help')
+  - title = t('.errors.title')
+  - help = t('.errors.help')
+  = render 'bootstrap/alert' do
+    %h4= title
+    %p= help
 
     %ul
       - post.errors.each do |attribute, errors|
diff --git a/app/views/posts/_submit.haml b/app/views/posts/_submit.haml
index b21b5ff2..cad43320 100644
--- a/app/views/posts/_submit.haml
+++ b/app/views/posts/_submit.haml
@@ -1,6 +1,6 @@
 .form-group
   = submit_tag t('.save'), class: 'btn submit-post'
-  .invalid-help.alert.alert-danger.d-none
+  = render 'bootstrap/alert', class: 'invalid-help d-none' do
     = site.config.fetch('invalid_help', t('.invalid_help'))
-  .sending-help.alert.alert-success.d-none
+  = render 'bootstrap/alert', class: 'sending-help d-none' do
     = site.config.fetch('sending_help', t('.sending_help'))
diff --git a/app/views/posts/attributes/_content.haml b/app/views/posts/attributes/_content.haml
index 36b88872..5db023fb 100644
--- a/app/views/posts/attributes/_content.haml
+++ b/app/views/posts/attributes/_content.haml
@@ -6,7 +6,7 @@
   .editor{ id: attribute, data: { editor: '' } }
     -# Esto es para luego decirle al navegador que se olvide estas cosas.
     = hidden_field_tag 'storage_keys[]', "#{request.original_url}##{attribute}", data: { target: 'storage-key' }
-    .alert.alert-info
+    = render 'bootstrap/alert' do
       :markdown
         #{t('editor.alert')}
     = text_area_tag "#{base}[#{attribute}]", '',
@@ -123,7 +123,7 @@
           %label{ for: 'link-url' }= t('editor.url')
           %input.form-control{ type: 'url', id: 'link-url', name: 'link-url' }/
 
-      .editor-aviso-word.alert.alert-info
+      = render 'bootstrap/alert', class: 'editor-aviso-word' do
         %p= t('editor.word')
 
     .editor-content.form-control.h-auto.mt-1{ contenteditable: 'true' }
diff --git a/app/views/posts/index.haml b/app/views/posts/index.haml
index a82616d8..dbeddaad 100644
--- a/app/views/posts/index.haml
+++ b/app/views/posts/index.haml
@@ -34,14 +34,13 @@
     = render 'sites/build', site: @site
 
     - if @site.design.credits
-      .alert.alert-primary{ role: 'alert' }
+      = render 'bootstrap/alert' do
         = sanitize_markdown @site.design.credits
         = link_to t('sites.donations.text'), t('sites.donations.url'), class: 'btn'
         - if @site.design.designer_url
           = link_to t('sites.designer_url'), @site.design.designer_url, class: 'btn'
 
   %section.col
-    = render 'layouts/flash'
     .d-flex.justify-content-between.align-items-center.pl-2-plus.pr-2-plus.mb-2
       %form{ action: site_posts_path }
         - @filter_params.each do |param, value|
diff --git a/app/views/sites/_form.haml b/app/views/sites/_form.haml
index 9a044c7f..757b8b48 100644
--- a/app/views/sites/_form.haml
+++ b/app/views/sites/_form.haml
@@ -1,7 +1,9 @@
 - unless site.errors.empty?
-  .alert.alert-info
-    %h4= t('.errors.title')
-    %p.lead= t('.errors.help')
+  - title = t('.errors.title')
+  - help = t('.errors.help')
+  = render 'bootstrap/alert' do
+    %h4= title
+    %p.lead= help
     %ul
       - site.errors.messages.each_pair do |attr, error|
         - attr = attr.to_s
@@ -48,7 +50,7 @@
     %h2= t('.design.title')
     %p.lead= t('.help.design')
     - if invalid? site, :design_id
-      .alert.alert-info
+      = render 'bootstrap/alert' do
         = t('activerecord.errors.models.site.attributes.design_id.layout_incompatible.help',
           layouts: site.incompatible_layouts.to_sentence)
     .row.designs
diff --git a/config/locales/devise.views.en.yml b/config/locales/devise.views.en.yml
index fd041b33..793f3a0a 100644
--- a/config/locales/devise.views.en.yml
+++ b/config/locales/devise.views.en.yml
@@ -104,7 +104,7 @@ en:
       new:
         sign_up: Sign up
         help: We only ask for an e-mail address and a password.  The password is safely stored, no one else besides you knows it!  You'll also receive an e-mail to confirm your account.
-      signed_up: Welcome! You have signed up successfully.
+      signed_up: "A message with a confirmation link has been sent to your email address. Please follow the link to activate your account."
       signed_up_but_inactive: You have signed up successfully. However, we could not sign you in because your account is not yet activated.
       signed_up_but_locked: You have signed up successfully. However, we could not sign you in because your account is locked.
       signed_up_but_unconfirmed: A message with a confirmation link has been sent to your email address. Please follow the link to activate your account.
@@ -138,7 +138,7 @@ en:
   errors:
     messages:
       already_confirmed: was already confirmed, please try signing in
-      confirmation_period_expired: needs to be confirmed within %{period}, please request a new one
+      confirmation_period_expired: "wasn't confirmed within %{period}. Please request a new confirmation link by using the \"Resend confirmation instructions\" button below and find it in your inbox."
       expired: has expired, please request a new one
       not_found: not found
       not_locked: was not locked
diff --git a/config/locales/devise.views.es.yml b/config/locales/devise.views.es.yml
index 73166afc..b745fc5f 100644
--- a/config/locales/devise.views.es.yml
+++ b/config/locales/devise.views.es.yml
@@ -104,7 +104,7 @@ es:
       new:
         sign_up: Registrarme
         help: Para registrarte solo pedimos una dirección de correo y una contraseña.  La contraseña se almacena de forma segura, ¡nadie más que vos la sabe!  Recibirás un correo de confirmación de cuenta.
-      signed_up: Bienvenide. Tu cuenta fue creada.
+      signed_up: "Hemos enviado un mensaje con un enlace de confirmación a tu correo electrónico. Por favor, abrí el enlace para terminar de activar tu cuenta."
       signed_up_but_inactive: Tu cuenta ha sido creada correctamente. Sin embargo, no hemos podido iniciar la sesión porque tu cuenta aún no está activada.
       signed_up_but_locked: Tu cuenta ha sido creada correctamente. Sin embargo, no hemos podido iniciar la sesión porque que tu cuenta está bloqueada.
       signed_up_but_unconfirmed: Para recibir actualizaciones, se ha enviado un mensaje con un enlace de confirmación a tu correo electrónico. Abre el enlace para activar tu cuenta.
@@ -138,7 +138,7 @@ es:
   errors:
     messages:
       already_confirmed: ya ha sido confirmada, por favor intenta iniciar sesión
-      confirmation_period_expired: necesita confirmarse dentro de %{period}, por favor solicita una nueva
+      confirmation_period_expired: "quedó sin confirmar luego de %{period}. Por favor, usa el botón \"Reenviar instrucciones de confirmación\" y busca el nuevo link en tu casilla."
       expired: ha expirado, por favor solicita una nueva
       not_found: no se ha encontrado
       not_locked: no estaba bloqueada